From 32f86e3657605b826891691a27a9bd19c45ca987 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 14:20:57 +0000
Subject: [PATCH 01/17] balance fetcher changes

---
 packages/assets-controller/CHANGELOG.md       |   5 +
 .../src/data-sources/RpcDataSource.test.ts    |  38 +-
 .../src/data-sources/RpcDataSource.ts         |  73 ++--
 .../data-sources/evm-rpc-services/index.ts    |   1 +
 .../services/BalanceFetcher.test.ts           | 343 ++++++++++--------
 .../services/BalanceFetcher.ts                | 170 +++++----
 .../evm-rpc-services/types/index.ts           |   2 +-
 .../evm-rpc-services/types/services.ts        |  15 +-
 8 files changed, 357 insertions(+), 290 deletions(-)

diff --git a/packages/assets-controller/CHANGELOG.md b/packages/assets-controller/CHANGELOG.md
index ef770496051..8380d20fb7d 100644
--- a/packages/assets-controller/CHANGELOG.md
+++ b/packages/assets-controller/CHANGELOG.md
@@ -7,8 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix `BalanceFetcher` producing incorrect native asset IDs for non-Ethereum EVM chains (e.g. Avalanche). Previously all native balances were hardcoded to `slip44:60` (ETH); now `BalanceFetcher` accepts CAIP-19 asset IDs from callers and preserves them in results, so `RpcDataSource` passes the correct chain-specific native identifier from `NetworkEnablementController.nativeAssetIdentifiers`.
+
 ### Changed
 
+- **BREAKING:** `BalanceFetcher.fetchBalancesForTokens` is renamed to `fetchBalancesForAssets` and now accepts `CaipAssetType[]` (CAIP-19 asset IDs) instead of `Address[]` token addresses. `BalanceFetcher.getTokensToFetch` is renamed to `getAssetIdsToFetch` and returns `CaipAssetType[]`. `BalanceFetchOptions.includeNative` and `BalanceFetcherConfig.includeNativeByDefault` are removed; include the native asset ID in the asset IDs array instead.
 - EVM RPC balance pipeline (`RpcDataSource`, `BalanceFetcher`, `TokenDetector`) no longer falls back to 18 decimals for ERC-20 when decimals are unknown; human-readable balances and `detectedBalances` entries are omitted until decimals are available from state, token list metadata, or on-chain `decimals()` (native token handling unchanged) ([#8267](https://github.com/MetaMask/core/pull/8267))
 - Bump `@metamask/keyring-api` from `^21.5.0` to `^21.6.0` ([#8259](https://github.com/MetaMask/core/pull/8259))
 
diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
index c6ce6eaf9ce..7be443576ed 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
@@ -476,7 +476,7 @@ describe('RpcDataSource', () => {
       const nativeAssetId = 'eip155:1/slip44:60' as Caip19AssetId;
       await withController(async ({ controller }) => {
         jest
-          .spyOn(BalanceFetcher.prototype, 'fetchBalancesForTokens')
+          .spyOn(BalanceFetcher.prototype, 'fetchBalancesForAssets')
           .mockResolvedValue({
             chainId: MOCK_CHAIN_ID_HEX,
             accountId: MOCK_ACCOUNT_ID,
@@ -565,7 +565,7 @@ describe('RpcDataSource', () => {
     it('initializes assetsBalance[accountId] in catch when first fetch for account throws', async () => {
       await withController(async ({ controller }) => {
         jest
-          .spyOn(BalanceFetcher.prototype, 'fetchBalancesForTokens')
+          .spyOn(BalanceFetcher.prototype, 'fetchBalancesForAssets')
           .mockRejectedValue(new Error('RPC unavailable'));
         const request = createDataRequest();
         const response = await controller.fetch(request);
@@ -759,12 +759,12 @@ describe('RpcDataSource', () => {
       );
     });
 
-    it('passes custom ERC20 token addresses to BalanceFetcher', async () => {
+    it('passes custom ERC20 asset entries (plus native) to BalanceFetcher', async () => {
       const customAssetId =
         'eip155:1/erc20:0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48' as Caip19AssetId;
 
       const fetchSpy = jest
-        .spyOn(BalanceFetcher.prototype, 'fetchBalancesForTokens')
+        .spyOn(BalanceFetcher.prototype, 'fetchBalancesForAssets')
         .mockResolvedValue(createBalanceFetchResult());
 
       await withController(async ({ controller }) => {
@@ -774,12 +774,18 @@ describe('RpcDataSource', () => {
         await controller.fetch(request);
 
         expect(fetchSpy).toHaveBeenCalledWith(
-          MOCK_CHAIN_ID_HEX,
           MOCK_ACCOUNT_ID,
           MOCK_ADDRESS,
-          ['0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48'],
-          { includeNative: true },
-          [],
+          [
+            {
+              assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
+              address: '0x0000000000000000000000000000000000000000',
+            },
+            expect.objectContaining({
+              assetId: customAssetId,
+              address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
+            }),
+          ],
         );
       });
 
@@ -793,7 +799,7 @@ describe('RpcDataSource', () => {
         'eip155:137/erc20:0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174' as Caip19AssetId;
 
       const fetchSpy = jest
-        .spyOn(BalanceFetcher.prototype, 'fetchBalancesForTokens')
+        .spyOn(BalanceFetcher.prototype, 'fetchBalancesForAssets')
         .mockResolvedValue(createBalanceFetchResult());
 
       await withController(async ({ controller }) => {
@@ -803,12 +809,18 @@ describe('RpcDataSource', () => {
         await controller.fetch(request);
 
         expect(fetchSpy).toHaveBeenCalledWith(
-          MOCK_CHAIN_ID_HEX,
           MOCK_ACCOUNT_ID,
           MOCK_ADDRESS,
-          ['0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48'],
-          { includeNative: true },
-          [],
+          [
+            {
+              assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
+              address: '0x0000000000000000000000000000000000000000',
+            },
+            expect.objectContaining({
+              assetId: matchingAsset,
+              address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
+            }),
+          ],
         );
       });
 
diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.ts b/packages/assets-controller/src/data-sources/RpcDataSource.ts
index da913d14ac9..cf49dd01b15 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.ts
@@ -41,11 +41,11 @@ import type {
 } from './evm-rpc-services';
 import type {
   Address,
+  AssetFetchEntry,
   Provider as RpcProvider,
   TokenListState,
   BalanceFetchResult,
   TokenDetectionResult,
-  TokenFetchInfo,
 } from './evm-rpc-services/types';
 import type {
   AssetsControllerGetStateAction,
@@ -66,6 +66,8 @@ import { normalizeAssetId } from '../utils';
 const CONTROLLER_NAME = 'RpcDataSource';
 const DEFAULT_BALANCE_INTERVAL = 30_000; // 30 seconds
 const DEFAULT_DETECTION_INTERVAL = 180_000; // 3 minutes
+const ZERO_ADDRESS: Address =
+  '0x0000000000000000000000000000000000000000' as Address;
 
 const log = createModuleLogger(projectLogger, CONTROLLER_NAME);
 
@@ -898,11 +900,15 @@ export class RpcDataSource extends AbstractDataSource<
       const { address, id: accountId } = account;
 
       for (const chainId of chainsForAccount) {
-        const hexChainId = caipChainIdToHex(chainId);
+        // Build a single AssetFetchEntry[] for native + custom ERC-20s
+        const nativeAssetId = this.#buildNativeAssetId(chainId);
+        const assetsToFetch: AssetFetchEntry[] = [
+          { assetId: nativeAssetId, address: ZERO_ADDRESS },
+        ];
 
-        // Extract ERC20 token addresses from customAssets for this chain
-        const customTokenAddresses: Address[] = [];
         if (request.customAssets) {
+          const existingMetadata = this.#getExistingAssetsMetadata();
+
           for (const assetId of request.customAssets) {
             try {
               const parsed = parseCaipAssetType(assetId);
@@ -911,7 +917,17 @@ export class RpcDataSource extends AbstractDataSource<
                 assetChainId === chainId &&
                 parsed.assetNamespace === 'erc20'
               ) {
-                customTokenAddresses.push(parsed.assetReference as Address);
+                const tokenAddress = parsed.assetReference as Address;
+                const normalizedId = normalizeAssetId(assetId);
+                const decimals =
+                  existingMetadata[normalizedId]?.decimals ??
+                  this.#getTokenMetadataFromTokenList(normalizedId)?.decimals;
+
+                assetsToFetch.push({
+                  assetId,
+                  address: tokenAddress.toLowerCase() as Address,
+                  decimals,
+                });
               }
             } catch {
               // Skip unparseable asset IDs
@@ -920,19 +936,10 @@ export class RpcDataSource extends AbstractDataSource<
         }
 
         try {
-          const tokenInfos = this.#tokenFetchInfosForCustomErc20s(
-            chainId,
-            customTokenAddresses,
-          );
-
-          // Use BalanceFetcher for batched balance fetching
-          const result = await this.#balanceFetcher.fetchBalancesForTokens(
-            hexChainId,
+          const result = await this.#balanceFetcher.fetchBalancesForAssets(
             accountId,
             address as Address,
-            customTokenAddresses,
-            { includeNative: true },
-            tokenInfos,
+            assetsToFetch,
           );
 
           if (!assetsBalance[accountId]) {
@@ -992,7 +999,6 @@ export class RpcDataSource extends AbstractDataSource<
           if (!assetsBalance[accountId]) {
             assetsBalance[accountId] = {};
           }
-          const nativeAssetId = this.#buildNativeAssetId(chainId);
           assetsBalance[accountId][nativeAssetId] = { amount: '0' };
 
           // Even on error, include native token metadata
@@ -1354,39 +1360,6 @@ export class RpcDataSource extends AbstractDataSource<
     return nativeAssetIdentifiers[chainId] ?? `${chainId}/slip44:60`;
   }
 
-  /**
-   * Build token infos for custom ERC-20s when decimals are already known from
-   * state or token list so BalanceFetcher can format balances; unknown decimals
-   * are left out and resolved in `fetch` / `#handleBalanceUpdate`.
-   *
-   * @param caipChainId - CAIP-2 chain id (e.g. `eip155:1`).
-   * @param tokenAddresses - ERC-20 contract addresses on that chain.
-   * @returns Token fetch infos that include only entries with known decimals.
-   */
-  #tokenFetchInfosForCustomErc20s(
-    caipChainId: ChainId,
-    tokenAddresses: Address[],
-  ): TokenFetchInfo[] {
-    const existingMetadata = this.#getExistingAssetsMetadata();
-    const infos: TokenFetchInfo[] = [];
-
-    for (const tokenAddress of tokenAddresses) {
-      const { reference } = parseCaipChainId(caipChainId);
-      const rawAssetId =
-        `eip155:${reference}/erc20:${tokenAddress.toLowerCase()}` as Caip19AssetId;
-      const assetId = normalizeAssetId(rawAssetId);
-      const decimals =
-        existingMetadata[assetId]?.decimals ??
-        this.#getTokenMetadataFromTokenList(assetId)?.decimals;
-
-      if (decimals !== undefined) {
-        infos.push({ address: tokenAddress, decimals });
-      }
-    }
-
-    return infos;
-  }
-
   /**
    * Get existing assets metadata from AssetsController state.
    * Used to include metadata for ERC20 tokens when returning balance updates.
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/index.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/index.ts
index e47693f7299..5b30f3b7d36 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/index.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/index.ts
@@ -1,5 +1,6 @@
 export type {
   Address,
+  AssetFetchEntry,
   AssetsBalanceState,
   ChainId,
   GetProviderFunction,
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
index d953496f0e3..779ff93b1fd 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
@@ -1,3 +1,5 @@
+import type { CaipAssetType } from '@metamask/utils';
+
 import { BalanceFetcher } from './BalanceFetcher';
 import type {
   BalanceFetcherConfig,
@@ -7,10 +9,10 @@ import type {
 import type { MulticallClient } from '../clients';
 import type {
   Address,
+  AssetFetchEntry,
   AssetsBalanceState,
   BalanceOfResponse,
   ChainId,
-  TokenFetchInfo,
 } from '../types';
 
 // =============================================================================
@@ -30,13 +32,30 @@ const ZERO_ADDRESS: Address =
 const MAINNET_CHAIN_ID: ChainId = '0x1' as ChainId;
 const POLYGON_CHAIN_ID: ChainId = '0x89' as ChainId;
 
-/** Decimals for TEST_TOKEN_1 (USDC) / TEST_TOKEN_2 (USDT) in fetch tests */
-const TEST_TOKEN_1_WITH_DECIMALS: TokenFetchInfo = {
-  address: TEST_TOKEN_1,
+const NATIVE_ETH_ASSET_ID = 'eip155:1/slip44:60' as CaipAssetType;
+const TOKEN_1_ASSET_ID =
+  `eip155:1/erc20:${TEST_TOKEN_1.toLowerCase()}` as CaipAssetType;
+const TOKEN_2_ASSET_ID =
+  `eip155:1/erc20:${TEST_TOKEN_2.toLowerCase()}` as CaipAssetType;
+
+const NATIVE_ETH_ENTRY: AssetFetchEntry = {
+  assetId: NATIVE_ETH_ASSET_ID,
+  address: ZERO_ADDRESS,
+};
+const TOKEN_1_ENTRY: AssetFetchEntry = {
+  assetId: TOKEN_1_ASSET_ID,
+  address: TEST_TOKEN_1.toLowerCase() as Address,
+};
+const TOKEN_1_ENTRY_WITH_DECIMALS: AssetFetchEntry = {
+  ...TOKEN_1_ENTRY,
   decimals: 6,
 };
-const TEST_TOKEN_2_WITH_DECIMALS: TokenFetchInfo = {
-  address: TEST_TOKEN_2,
+const TOKEN_2_ENTRY: AssetFetchEntry = {
+  assetId: TOKEN_2_ASSET_ID,
+  address: TEST_TOKEN_2.toLowerCase() as Address,
+};
+const TOKEN_2_ENTRY_WITH_DECIMALS: AssetFetchEntry = {
+  ...TOKEN_2_ENTRY,
   decimals: 6,
 };
 
@@ -151,7 +170,6 @@ describe('BalanceFetcher', () => {
           config: {
             defaultBatchSize: 100,
             defaultTimeoutMs: 60000,
-            includeNativeByDefault: false,
             pollingInterval: 45000,
           },
         },
@@ -183,35 +201,42 @@ describe('BalanceFetcher', () => {
 
   describe('setOnBalanceUpdate', () => {
     it('sets the balance update callback', async () => {
-      await withController(async ({ controller, mockMulticallClient }) => {
-        const mockCallback = jest.fn();
-        controller.setOnBalanceUpdate(mockCallback);
-
-        mockMulticallClient.batchBalanceOf.mockResolvedValue([
-          createMockBalanceResponse(
-            ZERO_ADDRESS,
-            TEST_ACCOUNT,
-            true,
-            '1000000000000000000',
-          ),
-        ]);
+      const mockState = createMockAssetsBalanceState(TEST_ACCOUNT_ID, {
+        [NATIVE_ETH_ASSET_ID]: { amount: '0' },
+      });
 
-        const input: BalancePollingInput = {
-          chainId: MAINNET_CHAIN_ID,
-          accountId: TEST_ACCOUNT_ID,
-          accountAddress: TEST_ACCOUNT,
-        };
+      await withController(
+        { assetsBalanceState: mockState },
+        async ({ controller, mockMulticallClient }) => {
+          const mockCallback = jest.fn();
+          controller.setOnBalanceUpdate(mockCallback);
 
-        await controller._executePoll(input);
+          mockMulticallClient.batchBalanceOf.mockResolvedValue([
+            createMockBalanceResponse(
+              ZERO_ADDRESS,
+              TEST_ACCOUNT,
+              true,
+              '1000000000000000000',
+            ),
+          ]);
 
-        expect(mockCallback).toHaveBeenCalledWith(
-          expect.objectContaining({
+          const input: BalancePollingInput = {
             chainId: MAINNET_CHAIN_ID,
             accountId: TEST_ACCOUNT_ID,
-            balances: expect.any(Array),
-          }),
-        );
-      });
+            accountAddress: TEST_ACCOUNT,
+          };
+
+          await controller._executePoll(input);
+
+          expect(mockCallback).toHaveBeenCalledWith(
+            expect.objectContaining({
+              chainId: MAINNET_CHAIN_ID,
+              accountId: TEST_ACCOUNT_ID,
+              balances: expect.any(Array),
+            }),
+          );
+        },
+      );
     });
 
     it('does not call callback when balances are empty', async () => {
@@ -285,55 +310,71 @@ describe('BalanceFetcher', () => {
     });
   });
 
-  describe('getTokensToFetch', () => {
+  describe('getAssetsToFetch', () => {
     it('returns empty array when no balances exist', async () => {
       await withController(async ({ controller }) => {
-        const tokens = controller.getTokensToFetch(
+        const entries = controller.getAssetsToFetch(
           MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
         );
-        expect(tokens).toStrictEqual([]);
+        expect(entries).toStrictEqual([]);
       });
     });
 
-    it('returns tokens from assetsBalance state', async () => {
+    it('returns asset fetch entries from assetsBalance state', async () => {
       const mockState = createMockAssetsBalanceState(TEST_ACCOUNT_ID, {
-        [`eip155:1/erc20:${TEST_TOKEN_1}`]: { amount: '100' },
-        [`eip155:1/erc20:${TEST_TOKEN_2}`]: { amount: '200' },
+        [NATIVE_ETH_ASSET_ID]: { amount: '1' },
+        [TOKEN_1_ASSET_ID]: { amount: '100' },
+        [TOKEN_2_ASSET_ID]: { amount: '200' },
       });
 
       await withController(
         { assetsBalanceState: mockState },
         async ({ controller }) => {
-          const tokens = controller.getTokensToFetch(
+          const entries = controller.getAssetsToFetch(
             MAINNET_CHAIN_ID,
             TEST_ACCOUNT_ID,
           );
-          expect(tokens).toHaveLength(2);
+          expect(entries).toHaveLength(3);
+
+          const assetIds = entries.map((e) => e.assetId);
+          expect(assetIds).toContain(NATIVE_ETH_ASSET_ID);
+          expect(assetIds).toContain(TOKEN_1_ASSET_ID);
+          expect(assetIds).toContain(TOKEN_2_ASSET_ID);
+
+          const nativeEntry = entries.find(
+            (e) => e.assetId === NATIVE_ETH_ASSET_ID,
+          );
+          expect(nativeEntry?.address).toBe(ZERO_ADDRESS);
+
+          const erc20Entry = entries.find(
+            (e) => e.assetId === TOKEN_1_ASSET_ID,
+          );
+          expect(erc20Entry?.address).toBe(TEST_TOKEN_1.toLowerCase());
         },
       );
     });
 
-    it('returns empty array when chain has no tokens', async () => {
+    it('returns empty array when chain has no assets', async () => {
       const mockState = createMockAssetsBalanceState(TEST_ACCOUNT_ID, {
-        [`eip155:1/erc20:${TEST_TOKEN_1}`]: { amount: '100' },
+        [TOKEN_1_ASSET_ID]: { amount: '100' },
       });
 
       await withController(
         { assetsBalanceState: mockState },
         async ({ controller }) => {
-          const tokens = controller.getTokensToFetch(
+          const entries = controller.getAssetsToFetch(
             POLYGON_CHAIN_ID,
             TEST_ACCOUNT_ID,
           );
-          expect(tokens).toStrictEqual([]);
+          expect(entries).toStrictEqual([]);
         },
       );
     });
   });
 
-  describe('fetchBalancesForTokens', () => {
-    it('fetches balances for specified token addresses', async () => {
+  describe('fetchBalancesForAssets', () => {
+    it('fetches balances for specified asset entries', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(
@@ -350,13 +391,10 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          undefined,
-          [TEST_TOKEN_1_WITH_DECIMALS],
+          [NATIVE_ETH_ENTRY, TOKEN_1_ENTRY_WITH_DECIMALS],
         );
 
         expect(result.balances).toHaveLength(2);
@@ -364,7 +402,7 @@ describe('BalanceFetcher', () => {
       });
     });
 
-    it('creates correct CAIP-19 asset ID for native token', async () => {
+    it('preserves the native asset ID provided by the caller', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(
@@ -375,45 +413,42 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [],
-          { includeNative: true },
+          [NATIVE_ETH_ENTRY],
         );
 
-        expect(result.balances[0].assetId).toBe('eip155:1/slip44:60');
+        expect(result.balances[0].assetId).toBe(NATIVE_ETH_ASSET_ID);
       });
     });
 
-    it('creates correct CAIP-19 asset ID for ERC-20 token', async () => {
+    it('preserves a non-ETH native asset ID (e.g. Avalanche)', async () => {
+      const avaxNativeAssetId =
+        'eip155:43114/slip44:9005' as CaipAssetType;
+
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(
-            TEST_TOKEN_1,
+            ZERO_ADDRESS,
             TEST_ACCOUNT,
             true,
-            '1000000000',
+            '5000000000000000000',
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [TEST_TOKEN_1_WITH_DECIMALS],
+          [{ assetId: avaxNativeAssetId, address: ZERO_ADDRESS }],
         );
 
-        expect(result.balances[0].assetId).toBe(
-          'eip155:1/erc20:0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
-        );
+        expect(result.balances[0].assetId).toBe(avaxNativeAssetId);
+        expect(result.balances[0].formattedBalance).toBe('5');
       });
     });
 
-    it('includes ERC-20 raw balance when tokenInfos are omitted (decimals resolved downstream)', async () => {
+    it('preserves the ERC-20 asset ID provided by the caller', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(
@@ -424,23 +459,17 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
+          [TOKEN_1_ENTRY_WITH_DECIMALS],
         );
 
-        expect(result.balances).toHaveLength(1);
-        expect(result.balances[0].decimals).toBeUndefined();
-        expect(result.balances[0].balance).toBe('1000000000');
-        expect(result.balances[0].formattedBalance).toBe('1000000000');
-        expect(result.failedAddresses).toHaveLength(0);
+        expect(result.balances[0].assetId).toBe(TOKEN_1_ASSET_ID);
       });
     });
 
-    it('includes ERC-20 raw balance when token info has no decimals', async () => {
+    it('includes ERC-20 raw balance when decimals omitted (resolved downstream)', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(
@@ -451,44 +480,30 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const tokenInfoMissingDecimals = {
-          address: TEST_TOKEN_1,
-        } as TokenFetchInfo;
-
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [tokenInfoMissingDecimals],
+          [TOKEN_1_ENTRY],
         );
 
         expect(result.balances).toHaveLength(1);
         expect(result.balances[0].decimals).toBeUndefined();
+        expect(result.balances[0].balance).toBe('1000000000');
         expect(result.balances[0].formattedBalance).toBe('1000000000');
         expect(result.failedAddresses).toHaveLength(0);
       });
     });
 
-    it('includes ERC-20 balance when token info has zero decimals', async () => {
+    it('includes ERC-20 balance when entry has zero decimals', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
           createMockBalanceResponse(TEST_TOKEN_1, TEST_ACCOUNT, true, '42'),
         ]);
 
-        const tokenInfoZeroDecimals: TokenFetchInfo = {
-          address: TEST_TOKEN_1,
-          decimals: 0,
-        };
-
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [tokenInfoZeroDecimals],
+          [{ ...TOKEN_1_ENTRY, decimals: 0 }],
         );
 
         expect(result.balances).toHaveLength(1);
@@ -503,12 +518,10 @@ describe('BalanceFetcher', () => {
           createMockBalanceResponse(TEST_TOKEN_1, TEST_ACCOUNT, false),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
+          [TOKEN_1_ENTRY],
         );
 
         expect(result.balances).toHaveLength(0);
@@ -516,30 +529,70 @@ describe('BalanceFetcher', () => {
       });
     });
 
-    it('returns empty result when no tokens to fetch', async () => {
-      await withController(
-        { config: { includeNativeByDefault: false } },
-        async ({ controller, mockMulticallClient }) => {
-          const result = await controller.fetchBalancesForTokens(
-            MAINNET_CHAIN_ID,
-            TEST_ACCOUNT_ID,
+    it('returns empty result when no entries provided', async () => {
+      await withController(async ({ controller, mockMulticallClient }) => {
+        const result = await controller.fetchBalancesForAssets(
+          TEST_ACCOUNT_ID,
+          TEST_ACCOUNT,
+          [],
+        );
+
+        expect(result).toStrictEqual({
+          chainId: '0x0',
+          accountId: TEST_ACCOUNT_ID,
+          accountAddress: TEST_ACCOUNT,
+          balances: [],
+          failedAddresses: [],
+          timestamp: 1700000000000,
+        });
+
+        expect(mockMulticallClient.batchBalanceOf).not.toHaveBeenCalled();
+      });
+    });
+
+    it('derives hex chainId from asset entries', async () => {
+      await withController(async ({ controller, mockMulticallClient }) => {
+        mockMulticallClient.batchBalanceOf.mockResolvedValue([
+          createMockBalanceResponse(
+            ZERO_ADDRESS,
             TEST_ACCOUNT,
-            [],
-            { includeNative: false },
-          );
+            true,
+            '1000000000000000000',
+          ),
+        ]);
 
-          expect(result).toStrictEqual({
-            chainId: MAINNET_CHAIN_ID,
-            accountId: TEST_ACCOUNT_ID,
-            accountAddress: TEST_ACCOUNT,
-            balances: [],
-            failedAddresses: [],
-            timestamp: 1700000000000,
-          });
+        const result = await controller.fetchBalancesForAssets(
+          TEST_ACCOUNT_ID,
+          TEST_ACCOUNT,
+          [NATIVE_ETH_ENTRY],
+        );
 
-          expect(mockMulticallClient.batchBalanceOf).not.toHaveBeenCalled();
-        },
-      );
+        expect(result.chainId).toBe(MAINNET_CHAIN_ID);
+      });
+    });
+
+    it('deduplicates entries with same address', async () => {
+      await withController(async ({ controller, mockMulticallClient }) => {
+        mockMulticallClient.batchBalanceOf.mockResolvedValue([
+          createMockBalanceResponse(
+            ZERO_ADDRESS,
+            TEST_ACCOUNT,
+            true,
+            '1000000000000000000',
+          ),
+        ]);
+
+        const result = await controller.fetchBalancesForAssets(
+          TEST_ACCOUNT_ID,
+          TEST_ACCOUNT,
+          [NATIVE_ETH_ENTRY, NATIVE_ETH_ENTRY],
+        );
+
+        expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(1);
+        const calls = mockMulticallClient.batchBalanceOf.mock.calls[0];
+        expect(calls[1]).toHaveLength(1);
+        expect(result.balances).toHaveLength(1);
+      });
     });
   });
 
@@ -555,13 +608,10 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [{ address: TEST_TOKEN_1, decimals: 6, symbol: 'USDC' }],
+          [{ ...TOKEN_1_ENTRY, decimals: 6, symbol: 'USDC' }],
         );
 
         expect(result.balances[0].formattedBalance).toBe('1234.56789');
@@ -574,13 +624,10 @@ describe('BalanceFetcher', () => {
           createMockBalanceResponse(TEST_TOKEN_1, TEST_ACCOUNT, true, '0'),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [TEST_TOKEN_1_WITH_DECIMALS],
+          [TOKEN_1_ENTRY_WITH_DECIMALS],
         );
 
         expect(result.balances[0].formattedBalance).toBe('0');
@@ -598,13 +645,10 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [TEST_TOKEN_1_WITH_DECIMALS],
+          [TOKEN_1_ENTRY_WITH_DECIMALS],
         );
 
         expect(result.balances[0].balance).toBe('0');
@@ -623,13 +667,10 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1],
-          { includeNative: false },
-          [TEST_TOKEN_1_WITH_DECIMALS],
+          [TOKEN_1_ENTRY_WITH_DECIMALS],
         );
 
         expect(result.balances[0].formattedBalance).toBe('invalid-balance');
@@ -649,13 +690,11 @@ describe('BalanceFetcher', () => {
           ),
         ]);
 
-        await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1, TEST_TOKEN_2],
-          { includeNative: false, batchSize: 1 },
-          [TEST_TOKEN_1_WITH_DECIMALS, TEST_TOKEN_2_WITH_DECIMALS],
+          [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
+          { batchSize: 1 },
         );
 
         expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
@@ -682,13 +721,11 @@ describe('BalanceFetcher', () => {
             ),
           ]);
 
-        const result = await controller.fetchBalancesForTokens(
-          MAINNET_CHAIN_ID,
+        const result = await controller.fetchBalancesForAssets(
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [TEST_TOKEN_1, TEST_TOKEN_2],
-          { includeNative: false, batchSize: 1 },
-          [TEST_TOKEN_1_WITH_DECIMALS, TEST_TOKEN_2_WITH_DECIMALS],
+          [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
+          { batchSize: 1 },
         );
 
         expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 0de7d311238..4356f28f28d 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -1,18 +1,17 @@
 import { StaticIntervalPollingControllerOnly } from '@metamask/polling-controller';
-import type { CaipAssetType } from '@metamask/utils';
 
 import type { MulticallClient } from '../clients';
 import type {
   AccountId,
   Address,
   AssetBalance,
+  AssetFetchEntry,
   AssetsBalanceState,
   BalanceFetchOptions,
   BalanceFetchResult,
   BalanceOfRequest,
   BalanceOfResponse,
   ChainId,
-  TokenFetchInfo,
 } from '../types';
 import { reduceInBatchesSerially } from '../utils';
 
@@ -31,7 +30,6 @@ export type BalanceFetcherMessenger = {
 export type BalanceFetcherConfig = {
   defaultBatchSize?: number;
   defaultTimeoutMs?: number;
-  includeNativeByDefault?: boolean;
   /** Polling interval in ms (default: 30s) */
   pollingInterval?: number;
 };
@@ -58,6 +56,11 @@ export type OnBalanceUpdateCallback = (
 /**
  * BalanceFetcher - Fetches token balances via multicall.
  * Extends StaticIntervalPollingControllerOnly for built-in polling support.
+ *
+ * Callers provide CAIP-19 asset IDs; the fetcher extracts on-chain addresses
+ * (or uses the zero address for native assets) and maps multicall responses
+ * back to the original asset IDs. This ensures the returned balance entries
+ * always carry the correct identifier regardless of chain.
  */
 export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalancePollingInput>() {
   readonly #multicallClient: MulticallClient;
@@ -79,7 +82,6 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     this.#config = {
       defaultBatchSize: config?.defaultBatchSize ?? 300,
       defaultTimeoutMs: config?.defaultTimeoutMs ?? 30000,
-      includeNativeByDefault: config?.includeNativeByDefault ?? true,
     };
 
     // Set the polling interval
@@ -113,7 +115,15 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     }
   }
 
-  getTokensToFetch(chainId: ChainId, accountId: AccountId): TokenFetchInfo[] {
+  /**
+   * Return asset fetch entries tracked in state for the given account and
+   * chain. Both native (`slip44:`) and ERC-20 (`erc20:`) entries are included.
+   *
+   * @param chainId - Hex chain ID (e.g. "0x1").
+   * @param accountId - Account UUID.
+   * @returns Array of asset fetch entries from state for the requested chain.
+   */
+  getAssetsToFetch(chainId: ChainId, accountId: AccountId): AssetFetchEntry[] {
     const state = this.#messenger.call('AssetsController:getState');
 
     if (!state?.assetsBalance) {
@@ -125,90 +135,91 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       return [];
     }
 
-    // Convert hex chainId to decimal for CAIP-2 matching
     const chainIdDecimal = parseInt(chainId, 16);
     const caipChainPrefix = `eip155:${chainIdDecimal}/`;
 
-    const tokenMap = new Map<string, TokenFetchInfo>();
-
-    for (const assetId of Object.keys(accountBalances)) {
-      // Only process ERC20 tokens on the current chain
-      if (assetId.startsWith(caipChainPrefix) && assetId.includes('/erc20:')) {
-        // Parse token address from CAIP-19: eip155:1/erc20:0x...
-        const tokenAddress = assetId.split('/erc20:')[1] as Address;
-        if (tokenAddress) {
-          const lowerAddress = tokenAddress.toLowerCase();
-          if (!tokenMap.has(lowerAddress)) {
-            tokenMap.set(lowerAddress, {
-              address: tokenAddress,
-              symbol: '',
-            });
-          }
+    const seen = new Set<string>();
+    const entries: AssetFetchEntry[] = [];
+
+    for (const rawAssetId of Object.keys(accountBalances)) {
+      if (rawAssetId.startsWith(caipChainPrefix)) {
+        const lower = rawAssetId.toLowerCase();
+        if (!seen.has(lower)) {
+          seen.add(lower);
+          entries.push(BalanceFetcher.#assetIdToEntry(rawAssetId));
         }
       }
     }
 
-    return Array.from(tokenMap.values());
+    return entries;
   }
 
+  /**
+   * Fetch balances for assets already tracked in state for the given
+   * account and chain.
+   *
+   * @param chainId - Hex chain ID.
+   * @param accountId - Account UUID.
+   * @param accountAddress - On-chain address of the account.
+   * @param options - Optional fetch options (batch size, timeout).
+   * @returns Balance fetch result.
+   */
   async fetchBalances(
     chainId: ChainId,
     accountId: AccountId,
     accountAddress: Address,
     options?: BalanceFetchOptions,
   ): Promise<BalanceFetchResult> {
-    const tokens = this.getTokensToFetch(chainId, accountId);
-    const tokenAddresses = tokens.map((token) => token.address);
+    const assets = this.getAssetsToFetch(chainId, accountId);
 
-    return this.fetchBalancesForTokens(
-      chainId,
+    return this.fetchBalancesForAssets(
       accountId,
       accountAddress,
-      tokenAddresses,
+      assets,
       options,
-      tokens,
     );
   }
 
-  async fetchBalancesForTokens(
-    chainId: ChainId,
+  /**
+   * Fetch balances for the given assets via multicall.
+   *
+   * Each entry bundles a CAIP-19 asset ID with its on-chain address and
+   * optional metadata (decimals, symbol), so callers never need to maintain
+   * separate parallel arrays.
+   *
+   * @param accountId - Account UUID.
+   * @param accountAddress - On-chain address of the account.
+   * @param assets - Asset fetch entries to fetch balances for.
+   * @param options - Optional fetch options (batch size, timeout).
+   * @returns Balance fetch result.
+   */
+  async fetchBalancesForAssets(
     accountId: AccountId,
     accountAddress: Address,
-    tokenAddresses: Address[],
+    assets: AssetFetchEntry[],
     options?: BalanceFetchOptions,
-    tokenInfos?: TokenFetchInfo[],
   ): Promise<BalanceFetchResult> {
     const batchSize = options?.batchSize ?? this.#config.defaultBatchSize;
-    const includeNative =
-      options?.includeNative ?? this.#config.includeNativeByDefault;
     const timestamp = Date.now();
 
-    const tokenInfoMap = new Map<string, TokenFetchInfo>();
-    if (tokenInfos) {
-      for (const info of tokenInfos) {
-        tokenInfoMap.set(info.address.toLowerCase(), info);
-      }
-    }
-
+    // Build a single map keyed by lowercase address that holds all info
+    // needed to match multicall responses back to their original entries.
     const balanceRequests: BalanceOfRequest[] = [];
+    const entryByAddress = new Map<string, AssetFetchEntry>();
 
-    if (includeNative) {
-      balanceRequests.push({
-        tokenAddress: ZERO_ADDRESS,
-        accountAddress,
-      });
-    }
+    for (const entry of assets) {
+      const lowerAddress = entry.address.toLowerCase();
+      if (entryByAddress.has(lowerAddress)) {
+        continue; // deduplicate
+      }
 
-    for (const tokenAddress of tokenAddresses) {
-      balanceRequests.push({
-        tokenAddress,
-        accountAddress,
-      });
+      entryByAddress.set(lowerAddress, entry);
+      balanceRequests.push({ tokenAddress: entry.address, accountAddress });
     }
 
     if (balanceRequests.length === 0) {
       return {
-        chainId,
+        chainId: '0x0' as ChainId,
         accountId,
         accountAddress,
         balances: [],
@@ -217,6 +228,10 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       };
     }
 
+    // Derive hex chainId from the first entry's asset ID
+    const chainRef = assets[0].assetId.split('/')[0].split(':')[1];
+    const chainId: ChainId = `0x${parseInt(chainRef, 10).toString(16)}`;
+
     type FetchAccumulator = {
       balances: AssetBalance[];
       failedAddresses: Address[];
@@ -244,7 +259,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
           chainId,
           accountId,
           timestamp,
-          tokenInfoMap,
+          entryByAddress,
         );
       },
     });
@@ -258,6 +273,29 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     };
   }
 
+  /**
+   * Convert a raw CAIP-19 asset ID string into an {@link AssetFetchEntry}.
+   *
+   * @param rawAssetId - CAIP-19 asset ID string.
+   * @returns An entry with the address extracted (zero address for native).
+   */
+  static #assetIdToEntry(rawAssetId: string): AssetFetchEntry {
+    const isNative = rawAssetId.includes('/slip44:');
+    let address: Address;
+
+    if (isNative) {
+      address = ZERO_ADDRESS;
+    } else {
+      const erc20Part = rawAssetId.split('/erc20:')[1];
+      address = erc20Part ? (erc20Part.toLowerCase() as Address) : ZERO_ADDRESS;
+    }
+
+    return {
+      assetId: rawAssetId as AssetFetchEntry['assetId'],
+      address,
+    };
+  }
+
   #processBalanceResponses(
     responses: BalanceOfResponse[],
     accumulator: {
@@ -267,7 +305,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     chainId: ChainId,
     accountId: AccountId,
     timestamp: number,
-    tokenInfoMap: Map<string, TokenFetchInfo>,
+    entryByAddress: Map<string, AssetFetchEntry>,
   ): {
     balances: AssetBalance[];
     failedAddresses: Address[];
@@ -280,31 +318,29 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
         continue;
       }
 
+      const lowerAddress = response.tokenAddress.toLowerCase();
+      const entry = entryByAddress.get(lowerAddress);
+      if (!entry) {
+        continue;
+      }
+
       const balance = response.balance ?? '0';
-      const chainIdDecimal = parseInt(chainId, 16);
-      const isNative =
-        response.tokenAddress.toLowerCase() === ZERO_ADDRESS.toLowerCase();
-      const tokenInfo = tokenInfoMap.get(response.tokenAddress.toLowerCase());
+      const isNative = lowerAddress === ZERO_ADDRESS.toLowerCase();
 
-      // Native uses 18. ERC-20: format when decimals are known; otherwise pass raw
-      // `balance` through so RpcDataSource can resolve decimals (state → list → RPC).
       let decimals: number | undefined;
       let formattedBalance: string;
       if (isNative) {
         decimals = 18;
         formattedBalance = this.#formatBalance(balance, decimals);
-      } else if (tokenInfo?.decimals === undefined) {
+      } else if (entry.decimals === undefined) {
         formattedBalance = balance;
       } else {
-        decimals = tokenInfo.decimals;
+        decimals = entry.decimals;
         formattedBalance = this.#formatBalance(balance, decimals);
       }
-      const assetId: CaipAssetType = isNative
-        ? (`eip155:${chainIdDecimal}/slip44:60` as CaipAssetType)
-        : (`eip155:${chainIdDecimal}/erc20:${response.tokenAddress.toLowerCase()}` as CaipAssetType);
 
       const balanceEntry: AssetBalance = {
-        assetId,
+        assetId: entry.assetId,
         accountId,
         chainId,
         balance,
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
index 7b94bc96a00..a084a23da31 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
@@ -26,9 +26,9 @@ export type { BalanceOfRequest, BalanceOfResponse } from './multicall';
 
 // Service types
 export type {
+  AssetFetchEntry,
   BalanceFetchOptions,
   BalanceFetchResult,
   TokenDetectionOptions,
   TokenDetectionResult,
-  TokenFetchInfo,
 } from './services';
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
index 0e636d9458a..40be15606ac 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
@@ -1,5 +1,5 @@
 import type { Asset, AssetBalance } from './assets';
-import type { AccountId, Address, ChainId } from './core';
+import type { AccountId, Address, CaipAssetType, ChainId } from './core';
 
 /**
  * Token detection result.
@@ -65,15 +65,18 @@ export type BalanceFetchOptions = {
   batchSize?: number;
   /** Timeout for fetch in milliseconds */
   timeout?: number;
-  /** Include native token balance */
-  includeNative?: boolean;
 };
 
 /**
- * Token info for balance fetching.
+ * Entry describing a single asset to fetch a balance for.
+ * Bundles the CAIP-19 asset ID with the on-chain address (zero address for
+ * native assets) and optional metadata so that callers never need to maintain
+ * separate parallel arrays.
  */
-export type TokenFetchInfo = {
-  /** Token contract address */
+export type AssetFetchEntry = {
+  /** CAIP-19 asset type identifier */
+  assetId: CaipAssetType;
+  /** On-chain contract address (zero address for native assets) */
   address: Address;
   /** Token decimals (omit when unknown — balance fetcher returns raw balance for RpcDataSource to resolve). */
   decimals?: number;

From 1c7ff77cb7382058d48f75f7f4cc6f14be60a969 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 14:29:03 +0000
Subject: [PATCH 02/17] export constant

---
 .../assets-controller/src/data-sources/RpcDataSource.ts    | 3 +--
 .../evm-rpc-services/clients/MulticallClient.ts            | 7 +------
 .../evm-rpc-services/services/BalanceFetcher.ts            | 4 +---
 packages/assets-controller/src/utils/constants.ts          | 2 ++
 4 files changed, 5 insertions(+), 11 deletions(-)
 create mode 100644 packages/assets-controller/src/utils/constants.ts

diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.ts b/packages/assets-controller/src/data-sources/RpcDataSource.ts
index cf49dd01b15..fa86a051db2 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.ts
@@ -62,12 +62,11 @@ import type {
   Middleware,
 } from '../types';
 import { normalizeAssetId } from '../utils';
+import { ZERO_ADDRESS } from '../utils/constants';
 
 const CONTROLLER_NAME = 'RpcDataSource';
 const DEFAULT_BALANCE_INTERVAL = 30_000; // 30 seconds
 const DEFAULT_DETECTION_INTERVAL = 180_000; // 3 minutes
-const ZERO_ADDRESS: Address =
-  '0x0000000000000000000000000000000000000000' as Address;
 
 const log = createModuleLogger(projectLogger, CONTROLLER_NAME);
 
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/clients/MulticallClient.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/clients/MulticallClient.ts
index 7fa65e28dd3..d3e767dae22 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/clients/MulticallClient.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/clients/MulticallClient.ts
@@ -1,6 +1,7 @@
 import { Interface } from '@ethersproject/abi';
 import type { Hex } from '@metamask/utils';
 
+import { ZERO_ADDRESS } from '../../../utils/constants';
 import type {
   Address,
   BalanceOfRequest,
@@ -79,12 +80,6 @@ const erc20Interface = new Interface(ERC20_ABI);
 // CONSTANTS
 // =============================================================================
 
-/**
- * Zero address constant for native token.
- */
-const ZERO_ADDRESS: Address =
-  '0x0000000000000000000000000000000000000000' as Address;
-
 /**
  * Multicall3 contract addresses by chain ID.
  * Source: https://github.com/mds1/multicall/blob/main/deployments.json
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 4356f28f28d..a4e3011487a 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -1,5 +1,6 @@
 import { StaticIntervalPollingControllerOnly } from '@metamask/polling-controller';
 
+import { ZERO_ADDRESS } from '../../../utils/constants';
 import type { MulticallClient } from '../clients';
 import type {
   AccountId,
@@ -17,9 +18,6 @@ import { reduceInBatchesSerially } from '../utils';
 
 const DEFAULT_BALANCE_INTERVAL = 30_000; // 30 seconds
 
-const ZERO_ADDRESS: Address =
-  '0x0000000000000000000000000000000000000000' as Address;
-
 /**
  * Minimal messenger interface for BalanceFetcher.
  */
diff --git a/packages/assets-controller/src/utils/constants.ts b/packages/assets-controller/src/utils/constants.ts
new file mode 100644
index 00000000000..6e57f60ba8d
--- /dev/null
+++ b/packages/assets-controller/src/utils/constants.ts
@@ -0,0 +1,2 @@
+export const ZERO_ADDRESS =
+  '0x0000000000000000000000000000000000000000' as const;

From 9ba12541985c2fd04d953ee742652d79251b2005 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 14:46:35 +0000
Subject: [PATCH 03/17] restore chainId parameter

---
 .../assets-controller/src/data-sources/RpcDataSource.ts  | 3 +++
 .../evm-rpc-services/services/BalanceFetcher.ts          | 9 ++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.ts b/packages/assets-controller/src/data-sources/RpcDataSource.ts
index fa86a051db2..7d1faeac1a3 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.ts
@@ -899,6 +899,8 @@ export class RpcDataSource extends AbstractDataSource<
       const { address, id: accountId } = account;
 
       for (const chainId of chainsForAccount) {
+        const hexChainId = caipChainIdToHex(chainId);
+
         // Build a single AssetFetchEntry[] for native + custom ERC-20s
         const nativeAssetId = this.#buildNativeAssetId(chainId);
         const assetsToFetch: AssetFetchEntry[] = [
@@ -936,6 +938,7 @@ export class RpcDataSource extends AbstractDataSource<
 
         try {
           const result = await this.#balanceFetcher.fetchBalancesForAssets(
+            hexChainId,
             accountId,
             address as Address,
             assetsToFetch,
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index a4e3011487a..e0b12290bb1 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -171,6 +171,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     const assets = this.getAssetsToFetch(chainId, accountId);
 
     return this.fetchBalancesForAssets(
+      chainId,
       accountId,
       accountAddress,
       assets,
@@ -185,6 +186,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * optional metadata (decimals, symbol), so callers never need to maintain
    * separate parallel arrays.
    *
+   * @param chainId - Hex chain ID.
    * @param accountId - Account UUID.
    * @param accountAddress - On-chain address of the account.
    * @param assets - Asset fetch entries to fetch balances for.
@@ -192,6 +194,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @returns Balance fetch result.
    */
   async fetchBalancesForAssets(
+    chainId: ChainId,
     accountId: AccountId,
     accountAddress: Address,
     assets: AssetFetchEntry[],
@@ -217,7 +220,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
 
     if (balanceRequests.length === 0) {
       return {
-        chainId: '0x0' as ChainId,
+        chainId,
         accountId,
         accountAddress,
         balances: [],
@@ -226,10 +229,6 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       };
     }
 
-    // Derive hex chainId from the first entry's asset ID
-    const chainRef = assets[0].assetId.split('/')[0].split(':')[1];
-    const chainId: ChainId = `0x${parseInt(chainRef, 10).toString(16)}`;
-
     type FetchAccumulator = {
       balances: AssetBalance[];
       failedAddresses: Address[];

From e85496f6be41b4eeccc4be947a2a3bc988f3e960 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 15:02:26 +0000
Subject: [PATCH 04/17] refactors

---
 .../src/data-sources/RpcDataSource.ts         |   5 +-
 .../services/BalanceFetcher.test.ts           | 109 ++++++++++--------
 .../services/BalanceFetcher.ts                |   9 +-
 .../evm-rpc-services/types/index.ts           |   1 -
 .../evm-rpc-services/types/services.ts        |  10 --
 5 files changed, 68 insertions(+), 66 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.ts b/packages/assets-controller/src/data-sources/RpcDataSource.ts
index 7d1faeac1a3..f5f00cde2c1 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.ts
@@ -918,7 +918,8 @@ export class RpcDataSource extends AbstractDataSource<
                 assetChainId === chainId &&
                 parsed.assetNamespace === 'erc20'
               ) {
-                const tokenAddress = parsed.assetReference as Address;
+                const tokenAddress =
+                  parsed.assetReference.toLowerCase() as Address;
                 const normalizedId = normalizeAssetId(assetId);
                 const decimals =
                   existingMetadata[normalizedId]?.decimals ??
@@ -926,7 +927,7 @@ export class RpcDataSource extends AbstractDataSource<
 
                 assetsToFetch.push({
                   assetId,
-                  address: tokenAddress.toLowerCase() as Address,
+                  address: tokenAddress,
                   decimals,
                 });
               }
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
index 779ff93b1fd..157100d6d3c 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
@@ -392,6 +392,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [NATIVE_ETH_ENTRY, TOKEN_1_ENTRY_WITH_DECIMALS],
@@ -414,6 +415,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [NATIVE_ETH_ENTRY],
@@ -424,8 +426,7 @@ describe('BalanceFetcher', () => {
     });
 
     it('preserves a non-ETH native asset ID (e.g. Avalanche)', async () => {
-      const avaxNativeAssetId =
-        'eip155:43114/slip44:9005' as CaipAssetType;
+      const avaxNativeAssetId = 'eip155:43114/slip44:9005' as CaipAssetType;
 
       await withController(async ({ controller, mockMulticallClient }) => {
         mockMulticallClient.batchBalanceOf.mockResolvedValue([
@@ -438,6 +439,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [{ assetId: avaxNativeAssetId, address: ZERO_ADDRESS }],
@@ -460,6 +462,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY_WITH_DECIMALS],
@@ -481,6 +484,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY],
@@ -501,6 +505,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [{ ...TOKEN_1_ENTRY, decimals: 0 }],
@@ -519,6 +524,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY],
@@ -532,6 +538,7 @@ describe('BalanceFetcher', () => {
     it('returns empty result when no entries provided', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [],
@@ -562,6 +569,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [NATIVE_ETH_ENTRY],
@@ -583,6 +591,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [NATIVE_ETH_ENTRY, NATIVE_ETH_ENTRY],
@@ -609,6 +618,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [{ ...TOKEN_1_ENTRY, decimals: 6, symbol: 'USDC' }],
@@ -625,6 +635,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY_WITH_DECIMALS],
@@ -646,6 +657,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY_WITH_DECIMALS],
@@ -668,6 +680,7 @@ describe('BalanceFetcher', () => {
         ]);
 
         const result = await controller.fetchBalancesForAssets(
+          MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
           [TOKEN_1_ENTRY_WITH_DECIMALS],
@@ -680,57 +693,63 @@ describe('BalanceFetcher', () => {
 
   describe('batching behavior', () => {
     it('uses custom batch size from options', async () => {
-      await withController(async ({ controller, mockMulticallClient }) => {
-        mockMulticallClient.batchBalanceOf.mockResolvedValue([
-          createMockBalanceResponse(
-            TEST_TOKEN_1,
-            TEST_ACCOUNT,
-            true,
-            '1000000000',
-          ),
-        ]);
-
-        await controller.fetchBalancesForAssets(
-          TEST_ACCOUNT_ID,
-          TEST_ACCOUNT,
-          [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
-          { batchSize: 1 },
-        );
-
-        expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
-      });
-    });
-
-    it('accumulates results across multiple batches', async () => {
-      await withController(async ({ controller, mockMulticallClient }) => {
-        mockMulticallClient.batchBalanceOf
-          .mockResolvedValueOnce([
+      await withController(
+        { config: { defaultBatchSize: 1 } },
+        async ({ controller, mockMulticallClient }) => {
+          mockMulticallClient.batchBalanceOf.mockResolvedValue([
             createMockBalanceResponse(
               TEST_TOKEN_1,
               TEST_ACCOUNT,
               true,
-              '1000000',
-            ),
-          ])
-          .mockResolvedValueOnce([
-            createMockBalanceResponse(
-              TEST_TOKEN_2,
-              TEST_ACCOUNT,
-              true,
-              '2000000',
+              '1000000000',
             ),
           ]);
 
-        const result = await controller.fetchBalancesForAssets(
-          TEST_ACCOUNT_ID,
-          TEST_ACCOUNT,
-          [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
-          { batchSize: 1 },
-        );
+          await controller.fetchBalancesForAssets(
+            MAINNET_CHAIN_ID,
+            TEST_ACCOUNT_ID,
+            TEST_ACCOUNT,
+            [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
+          );
 
-        expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
-        expect(result.balances).toHaveLength(2);
-      });
+          expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
+        },
+      );
+    });
+
+    it('accumulates results across multiple batches', async () => {
+      await withController(
+        { config: { defaultBatchSize: 1 } },
+        async ({ controller, mockMulticallClient }) => {
+          mockMulticallClient.batchBalanceOf
+            .mockResolvedValueOnce([
+              createMockBalanceResponse(
+                TEST_TOKEN_1,
+                TEST_ACCOUNT,
+                true,
+                '1000000',
+              ),
+            ])
+            .mockResolvedValueOnce([
+              createMockBalanceResponse(
+                TEST_TOKEN_2,
+                TEST_ACCOUNT,
+                true,
+                '2000000',
+              ),
+            ]);
+
+          const result = await controller.fetchBalancesForAssets(
+            MAINNET_CHAIN_ID,
+            TEST_ACCOUNT_ID,
+            TEST_ACCOUNT,
+            [TOKEN_1_ENTRY_WITH_DECIMALS, TOKEN_2_ENTRY_WITH_DECIMALS],
+          );
+
+          expect(mockMulticallClient.batchBalanceOf).toHaveBeenCalledTimes(2);
+          expect(result.balances).toHaveLength(2);
+        },
+      );
     });
   });
 });
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index e0b12290bb1..76b87643e72 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -8,7 +8,6 @@ import type {
   AssetBalance,
   AssetFetchEntry,
   AssetsBalanceState,
-  BalanceFetchOptions,
   BalanceFetchResult,
   BalanceOfRequest,
   BalanceOfResponse,
@@ -159,14 +158,12 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @param chainId - Hex chain ID.
    * @param accountId - Account UUID.
    * @param accountAddress - On-chain address of the account.
-   * @param options - Optional fetch options (batch size, timeout).
    * @returns Balance fetch result.
    */
   async fetchBalances(
     chainId: ChainId,
     accountId: AccountId,
     accountAddress: Address,
-    options?: BalanceFetchOptions,
   ): Promise<BalanceFetchResult> {
     const assets = this.getAssetsToFetch(chainId, accountId);
 
@@ -175,7 +172,6 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       accountId,
       accountAddress,
       assets,
-      options,
     );
   }
 
@@ -190,7 +186,6 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @param accountId - Account UUID.
    * @param accountAddress - On-chain address of the account.
    * @param assets - Asset fetch entries to fetch balances for.
-   * @param options - Optional fetch options (batch size, timeout).
    * @returns Balance fetch result.
    */
   async fetchBalancesForAssets(
@@ -198,9 +193,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     accountId: AccountId,
     accountAddress: Address,
     assets: AssetFetchEntry[],
-    options?: BalanceFetchOptions,
   ): Promise<BalanceFetchResult> {
-    const batchSize = options?.batchSize ?? this.#config.defaultBatchSize;
     const timestamp = Date.now();
 
     // Build a single map keyed by lowercase address that holds all info
@@ -239,7 +232,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       FetchAccumulator
     >({
       values: balanceRequests,
-      batchSize,
+      batchSize: this.#config.defaultBatchSize,
       initialResult: {
         balances: [],
         failedAddresses: [],
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
index a084a23da31..ac9a8989041 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/types/index.ts
@@ -27,7 +27,6 @@ export type { BalanceOfRequest, BalanceOfResponse } from './multicall';
 // Service types
 export type {
   AssetFetchEntry,
-  BalanceFetchOptions,
   BalanceFetchResult,
   TokenDetectionOptions,
   TokenDetectionResult,
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
index 40be15606ac..6ffb7ce320a 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
@@ -57,16 +57,6 @@ export type BalanceFetchResult = {
   timestamp: number;
 };
 
-/**
- * Balance fetch options.
- */
-export type BalanceFetchOptions = {
-  /** Maximum number of tokens to fetch per batch */
-  batchSize?: number;
-  /** Timeout for fetch in milliseconds */
-  timeout?: number;
-};
-
 /**
  * Entry describing a single asset to fetch a balance for.
  * Bundles the CAIP-19 asset ID with the on-chain address (zero address for

From c71d3e29666cdbe07de7591b9c3815de8671a186 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 15:15:07 +0000
Subject: [PATCH 05/17] more changes

---
 .../evm-rpc-services/services/BalanceFetcher.test.ts      | 2 +-
 .../evm-rpc-services/services/BalanceFetcher.ts           | 3 +--
 .../src/data-sources/evm-rpc-services/types/services.ts   | 8 +++-----
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
index 157100d6d3c..ecdf2a3d503 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
@@ -621,7 +621,7 @@ describe('BalanceFetcher', () => {
           MAINNET_CHAIN_ID,
           TEST_ACCOUNT_ID,
           TEST_ACCOUNT,
-          [{ ...TOKEN_1_ENTRY, decimals: 6, symbol: 'USDC' }],
+          [{ ...TOKEN_1_ENTRY, decimals: 6 }],
         );
 
         expect(result.balances[0].formattedBalance).toBe('1234.56789');
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 76b87643e72..ed44fb12d6f 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -179,8 +179,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * Fetch balances for the given assets via multicall.
    *
    * Each entry bundles a CAIP-19 asset ID with its on-chain address and
-   * optional metadata (decimals, symbol), so callers never need to maintain
-   * separate parallel arrays.
+   * optional decimals.
    *
    * @param chainId - Hex chain ID.
    * @param accountId - Account UUID.
diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
index 6ffb7ce320a..ab5a89dd6a2 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/types/services.ts
@@ -60,16 +60,14 @@ export type BalanceFetchResult = {
 /**
  * Entry describing a single asset to fetch a balance for.
  * Bundles the CAIP-19 asset ID with the on-chain address (zero address for
- * native assets) and optional metadata so that callers never need to maintain
- * separate parallel arrays.
+ * native assets even when the chain has a native asset with a non-zero address)
+ * and optional metadata
  */
 export type AssetFetchEntry = {
   /** CAIP-19 asset type identifier */
   assetId: CaipAssetType;
-  /** On-chain contract address (zero address for native assets) */
+  /** On-chain contract address (zero address for native assets regardless of the chain's native asset address) */
   address: Address;
   /** Token decimals (omit when unknown — balance fetcher returns raw balance for RpcDataSource to resolve). */
   decimals?: number;
-  /** Token symbol (optional) */
-  symbol?: string;
 };

From 3a4da245f3234f82712309f18ba9bbd8906f4d5a Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 15:16:50 +0000
Subject: [PATCH 06/17] fix test

---
 .../src/data-sources/RpcDataSource.test.ts    | 25 ++++++++-----------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
index 7be443576ed..0628c8b1ba1 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
@@ -774,6 +774,7 @@ describe('RpcDataSource', () => {
         await controller.fetch(request);
 
         expect(fetchSpy).toHaveBeenCalledWith(
+          MOCK_CHAIN_ID_HEX,
           MOCK_ACCOUNT_ID,
           MOCK_ADDRESS,
           [
@@ -808,20 +809,16 @@ describe('RpcDataSource', () => {
         });
         await controller.fetch(request);
 
-        expect(fetchSpy).toHaveBeenCalledWith(
-          MOCK_ACCOUNT_ID,
-          MOCK_ADDRESS,
-          [
-            {
-              assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
-              address: '0x0000000000000000000000000000000000000000',
-            },
-            expect.objectContaining({
-              assetId: matchingAsset,
-              address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
-            }),
-          ],
-        );
+        expect(fetchSpy).toHaveBeenCalledWith(MOCK_ACCOUNT_ID, MOCK_ADDRESS, [
+          {
+            assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
+            address: '0x0000000000000000000000000000000000000000',
+          },
+          expect.objectContaining({
+            assetId: matchingAsset,
+            address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
+          }),
+        ]);
       });
 
       fetchSpy.mockRestore();

From 071f5f196fa40b2208efb90e37f8f0fe6c26d068 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 15:19:20 +0000
Subject: [PATCH 07/17] fix test

---
 .../evm-rpc-services/services/BalanceFetcher.test.ts            | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
index ecdf2a3d503..372e235e1ed 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
@@ -545,7 +545,7 @@ describe('BalanceFetcher', () => {
         );
 
         expect(result).toStrictEqual({
-          chainId: '0x0',
+          chainId: MAINNET_CHAIN_ID,
           accountId: TEST_ACCOUNT_ID,
           accountAddress: TEST_ACCOUNT,
           balances: [],

From eac5e7fc73de0f0599a5f2988ce74694a567856e Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 15:20:19 +0000
Subject: [PATCH 08/17] fix test

---
 .../src/data-sources/RpcDataSource.test.ts    | 25 +++++++++++--------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
index 0628c8b1ba1..1355065a592 100644
--- a/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
+++ b/packages/assets-controller/src/data-sources/RpcDataSource.test.ts
@@ -809,16 +809,21 @@ describe('RpcDataSource', () => {
         });
         await controller.fetch(request);
 
-        expect(fetchSpy).toHaveBeenCalledWith(MOCK_ACCOUNT_ID, MOCK_ADDRESS, [
-          {
-            assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
-            address: '0x0000000000000000000000000000000000000000',
-          },
-          expect.objectContaining({
-            assetId: matchingAsset,
-            address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
-          }),
-        ]);
+        expect(fetchSpy).toHaveBeenCalledWith(
+          MOCK_CHAIN_ID_HEX,
+          MOCK_ACCOUNT_ID,
+          MOCK_ADDRESS,
+          [
+            {
+              assetId: `${MOCK_CHAIN_ID_CAIP}/slip44:60`,
+              address: '0x0000000000000000000000000000000000000000',
+            },
+            expect.objectContaining({
+              assetId: matchingAsset,
+              address: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
+            }),
+          ],
+        );
       });
 
       fetchSpy.mockRestore();

From 1f79c0bdb37e5e4ca4478a30bf509b3b8c6caa62 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 16:16:29 +0000
Subject: [PATCH 09/17] refactor

---
 .../services/BalanceFetcher.ts                | 54 +++++++++----------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index ed44fb12d6f..852af853faa 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -1,4 +1,5 @@
 import { StaticIntervalPollingControllerOnly } from '@metamask/polling-controller';
+import { parseCaipAssetType } from '@metamask/utils';
 
 import { ZERO_ADDRESS } from '../../../utils/constants';
 import type { MulticallClient } from '../clients';
@@ -11,6 +12,7 @@ import type {
   BalanceFetchResult,
   BalanceOfRequest,
   BalanceOfResponse,
+  CaipAssetType,
   ChainId,
 } from '../types';
 import { reduceInBatchesSerially } from '../utils';
@@ -132,18 +134,35 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       return [];
     }
 
-    const chainIdDecimal = parseInt(chainId, 16);
-    const caipChainPrefix = `eip155:${chainIdDecimal}/`;
+    const chainIdDecimal = parseInt(chainId, 16).toString();
 
     const seen = new Set<string>();
     const entries: AssetFetchEntry[] = [];
 
-    for (const rawAssetId of Object.keys(accountBalances)) {
-      if (rawAssetId.startsWith(caipChainPrefix)) {
-        const lower = rawAssetId.toLowerCase();
+    for (const assetId of Object.keys(accountBalances) as CaipAssetType[]) {
+      const {
+        chain: { reference: chainReference },
+        assetNamespace,
+        assetReference,
+      } = parseCaipAssetType(assetId);
+      if (chainReference === chainIdDecimal) {
+        const lower = assetId.toLowerCase();
         if (!seen.has(lower)) {
           seen.add(lower);
-          entries.push(BalanceFetcher.#assetIdToEntry(rawAssetId));
+
+          const isNative = assetNamespace === 'slip44';
+
+          if (isNative) {
+            entries.push({
+              assetId,
+              address: ZERO_ADDRESS,
+            });
+          } else {
+            entries.push({
+              assetId,
+              address: assetReference.toLowerCase() as Address,
+            });
+          }
         }
       }
     }
@@ -262,29 +281,6 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
     };
   }
 
-  /**
-   * Convert a raw CAIP-19 asset ID string into an {@link AssetFetchEntry}.
-   *
-   * @param rawAssetId - CAIP-19 asset ID string.
-   * @returns An entry with the address extracted (zero address for native).
-   */
-  static #assetIdToEntry(rawAssetId: string): AssetFetchEntry {
-    const isNative = rawAssetId.includes('/slip44:');
-    let address: Address;
-
-    if (isNative) {
-      address = ZERO_ADDRESS;
-    } else {
-      const erc20Part = rawAssetId.split('/erc20:')[1];
-      address = erc20Part ? (erc20Part.toLowerCase() as Address) : ZERO_ADDRESS;
-    }
-
-    return {
-      assetId: rawAssetId as AssetFetchEntry['assetId'],
-      address,
-    };
-  }
-
   #processBalanceResponses(
     responses: BalanceOfResponse[],
     accumulator: {

From 8046bbe2b02db5c16830673132dd571344724524 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 16:58:08 +0000
Subject: [PATCH 10/17] remove changelog entry

---
 packages/assets-controller/CHANGELOG.md | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/packages/assets-controller/CHANGELOG.md b/packages/assets-controller/CHANGELOG.md
index 8380d20fb7d..ef770496051 100644
--- a/packages/assets-controller/CHANGELOG.md
+++ b/packages/assets-controller/CHANGELOG.md
@@ -7,13 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-### Fixed
-
-- Fix `BalanceFetcher` producing incorrect native asset IDs for non-Ethereum EVM chains (e.g. Avalanche). Previously all native balances were hardcoded to `slip44:60` (ETH); now `BalanceFetcher` accepts CAIP-19 asset IDs from callers and preserves them in results, so `RpcDataSource` passes the correct chain-specific native identifier from `NetworkEnablementController.nativeAssetIdentifiers`.
-
 ### Changed
 
-- **BREAKING:** `BalanceFetcher.fetchBalancesForTokens` is renamed to `fetchBalancesForAssets` and now accepts `CaipAssetType[]` (CAIP-19 asset IDs) instead of `Address[]` token addresses. `BalanceFetcher.getTokensToFetch` is renamed to `getAssetIdsToFetch` and returns `CaipAssetType[]`. `BalanceFetchOptions.includeNative` and `BalanceFetcherConfig.includeNativeByDefault` are removed; include the native asset ID in the asset IDs array instead.
 - EVM RPC balance pipeline (`RpcDataSource`, `BalanceFetcher`, `TokenDetector`) no longer falls back to 18 decimals for ERC-20 when decimals are unknown; human-readable balances and `detectedBalances` entries are omitted until decimals are available from state, token list metadata, or on-chain `decimals()` (native token handling unchanged) ([#8267](https://github.com/MetaMask/core/pull/8267))
 - Bump `@metamask/keyring-api` from `^21.5.0` to `^21.6.0` ([#8259](https://github.com/MetaMask/core/pull/8259))
 

From 9213566de02f7f896e81cc6b4c9c79f456ebc606 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 17:02:46 +0000
Subject: [PATCH 11/17] refactor

---
 .../services/BalanceFetcher.ts                | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 852af853faa..1ccc0814b15 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -152,17 +152,14 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
 
           const isNative = assetNamespace === 'slip44';
 
-          if (isNative) {
-            entries.push({
-              assetId,
-              address: ZERO_ADDRESS,
-            });
-          } else {
-            entries.push({
-              assetId,
-              address: assetReference.toLowerCase() as Address,
-            });
-          }
+          const tokenAddress = isNative
+            ? ZERO_ADDRESS
+            : (assetReference.toLowerCase() as Address);
+
+          entries.push({
+            assetId,
+            address: tokenAddress,
+          });
         }
       }
     }

From 88d3c615c81e20bcd638b9999418b4e6eab160b1 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 17:09:59 +0000
Subject: [PATCH 12/17] make methods private

---
 .../evm-rpc-services/services/BalanceFetcher.ts           | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 1ccc0814b15..1eb82bfa582 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -103,7 +103,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @param input - The polling input.
    */
   async _executePoll(input: BalancePollingInput): Promise<void> {
-    const result = await this.fetchBalances(
+    const result = await this.#fetchBalances(
       input.chainId,
       input.accountId,
       input.accountAddress,
@@ -122,7 +122,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @param accountId - Account UUID.
    * @returns Array of asset fetch entries from state for the requested chain.
    */
-  getAssetsToFetch(chainId: ChainId, accountId: AccountId): AssetFetchEntry[] {
+  #getAssetsToFetch(chainId: ChainId, accountId: AccountId): AssetFetchEntry[] {
     const state = this.#messenger.call('AssetsController:getState');
 
     if (!state?.assetsBalance) {
@@ -176,12 +176,12 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
    * @param accountAddress - On-chain address of the account.
    * @returns Balance fetch result.
    */
-  async fetchBalances(
+  async #fetchBalances(
     chainId: ChainId,
     accountId: AccountId,
     accountAddress: Address,
   ): Promise<BalanceFetchResult> {
-    const assets = this.getAssetsToFetch(chainId, accountId);
+    const assets = this.#getAssetsToFetch(chainId, accountId);
 
     return this.fetchBalancesForAssets(
       chainId,

From 327aef2560b4075d5b44f96afb06db197105e184 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 17:15:43 +0000
Subject: [PATCH 13/17] refactor

---
 .../services/BalanceFetcher.ts                | 31 +++++++++----------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 1eb82bfa582..c060e0131b8 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -136,8 +136,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
 
     const chainIdDecimal = parseInt(chainId, 16).toString();
 
-    const seen = new Set<string>();
-    const entries: AssetFetchEntry[] = [];
+    const assetsToFetch = new Map<string, AssetFetchEntry>();
 
     for (const assetId of Object.keys(accountBalances) as CaipAssetType[]) {
       const {
@@ -145,26 +144,26 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
         assetNamespace,
         assetReference,
       } = parseCaipAssetType(assetId);
-      if (chainReference === chainIdDecimal) {
-        const lower = assetId.toLowerCase();
-        if (!seen.has(lower)) {
-          seen.add(lower);
 
-          const isNative = assetNamespace === 'slip44';
+      if (chainReference === chainIdDecimal) {
+        const assetIdLowerCase = assetId.toLowerCase();
+        if (assetsToFetch.has(assetIdLowerCase)) {
+          continue;
+        }
 
-          const tokenAddress = isNative
-            ? ZERO_ADDRESS
-            : (assetReference.toLowerCase() as Address);
+        const isNative = assetNamespace === 'slip44';
+        const tokenAddress = isNative
+          ? ZERO_ADDRESS
+          : (assetReference.toLowerCase() as Address);
 
-          entries.push({
-            assetId,
-            address: tokenAddress,
-          });
-        }
+        assetsToFetch.set(assetIdLowerCase, {
+          assetId,
+          address: tokenAddress,
+        });
       }
     }
 
-    return entries;
+    return Array.from(assetsToFetch.values());
   }
 
   /**

From ae422842e835427cff79b238d9cf7c18eb099682 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 17:17:25 +0000
Subject: [PATCH 14/17] comment

---
 .../data-sources/evm-rpc-services/services/BalanceFetcher.ts    | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index c060e0131b8..980a79fc588 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -134,6 +134,8 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
       return [];
     }
 
+    // Convert hex chainId to decimal for CAIP-2 matching
+    // This is safe because we are filtring with an accountId that is for evm balances only
     const chainIdDecimal = parseInt(chainId, 16).toString();
 
     const assetsToFetch = new Map<string, AssetFetchEntry>();

From 3b5b50613156f1fdcc6fff57e46e469702dcc17b Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 19:28:35 +0000
Subject: [PATCH 15/17] fix test

---
 .../services/BalanceFetcher.test.ts           | 63 -------------------
 1 file changed, 63 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
index 372e235e1ed..780be4a4ff0 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.test.ts
@@ -310,69 +310,6 @@ describe('BalanceFetcher', () => {
     });
   });
 
-  describe('getAssetsToFetch', () => {
-    it('returns empty array when no balances exist', async () => {
-      await withController(async ({ controller }) => {
-        const entries = controller.getAssetsToFetch(
-          MAINNET_CHAIN_ID,
-          TEST_ACCOUNT_ID,
-        );
-        expect(entries).toStrictEqual([]);
-      });
-    });
-
-    it('returns asset fetch entries from assetsBalance state', async () => {
-      const mockState = createMockAssetsBalanceState(TEST_ACCOUNT_ID, {
-        [NATIVE_ETH_ASSET_ID]: { amount: '1' },
-        [TOKEN_1_ASSET_ID]: { amount: '100' },
-        [TOKEN_2_ASSET_ID]: { amount: '200' },
-      });
-
-      await withController(
-        { assetsBalanceState: mockState },
-        async ({ controller }) => {
-          const entries = controller.getAssetsToFetch(
-            MAINNET_CHAIN_ID,
-            TEST_ACCOUNT_ID,
-          );
-          expect(entries).toHaveLength(3);
-
-          const assetIds = entries.map((e) => e.assetId);
-          expect(assetIds).toContain(NATIVE_ETH_ASSET_ID);
-          expect(assetIds).toContain(TOKEN_1_ASSET_ID);
-          expect(assetIds).toContain(TOKEN_2_ASSET_ID);
-
-          const nativeEntry = entries.find(
-            (e) => e.assetId === NATIVE_ETH_ASSET_ID,
-          );
-          expect(nativeEntry?.address).toBe(ZERO_ADDRESS);
-
-          const erc20Entry = entries.find(
-            (e) => e.assetId === TOKEN_1_ASSET_ID,
-          );
-          expect(erc20Entry?.address).toBe(TEST_TOKEN_1.toLowerCase());
-        },
-      );
-    });
-
-    it('returns empty array when chain has no assets', async () => {
-      const mockState = createMockAssetsBalanceState(TEST_ACCOUNT_ID, {
-        [TOKEN_1_ASSET_ID]: { amount: '100' },
-      });
-
-      await withController(
-        { assetsBalanceState: mockState },
-        async ({ controller }) => {
-          const entries = controller.getAssetsToFetch(
-            POLYGON_CHAIN_ID,
-            TEST_ACCOUNT_ID,
-          );
-          expect(entries).toStrictEqual([]);
-        },
-      );
-    });
-  });
-
   describe('fetchBalancesForAssets', () => {
     it('fetches balances for specified asset entries', async () => {
       await withController(async ({ controller, mockMulticallClient }) => {

From 58d500b397c3245c1aade738628e2adebdd5dc0f Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Tue, 24 Mar 2026 19:32:46 +0000
Subject: [PATCH 16/17] better coverage

---
 .../evm-rpc-services/services/BalanceFetcher.ts             | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
index 980a79fc588..4c4a6a4b429 100644
--- a/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
+++ b/packages/assets-controller/src/data-sources/evm-rpc-services/services/BalanceFetcher.ts
@@ -125,11 +125,7 @@ export class BalanceFetcher extends StaticIntervalPollingControllerOnly<BalanceP
   #getAssetsToFetch(chainId: ChainId, accountId: AccountId): AssetFetchEntry[] {
     const state = this.#messenger.call('AssetsController:getState');
 
-    if (!state?.assetsBalance) {
-      return [];
-    }
-
-    const accountBalances = state.assetsBalance[accountId];
+    const accountBalances = state?.assetsBalance?.[accountId];
     if (!accountBalances) {
       return [];
     }

From 4ab304a9aefce0afb330fd663247e58e1bbff516 Mon Sep 17 00:00:00 2001
From: Bernardo Garces Chapero <bernardo.chapero@consensys.net>
Date: Wed, 25 Mar 2026 10:13:55 +0000
Subject: [PATCH 17/17] submit changelog

---
 packages/assets-controller/CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/assets-controller/CHANGELOG.md b/packages/assets-controller/CHANGELOG.md
index 06d1e87c326..6838457ed3f 100644
--- a/packages/assets-controller/CHANGELOG.md
+++ b/packages/assets-controller/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Refactored `BalanceFetcher` and `RpcDataSource` to ensure the correct `assetId` is used for EVM native assets that are not ETH ([#8284](https://github.com/MetaMask/core/pull/8284))
+
 ## [3.1.0]
 
 ### Changed