diff --git a/src/app/wallets/get-balance-for-wallet.ts b/src/app/wallets/get-balance-for-wallet.ts
index 46ddf6cad..7a2a0b945 100644
--- a/src/app/wallets/get-balance-for-wallet.ts
+++ b/src/app/wallets/get-balance-for-wallet.ts
@@ -1,7 +1,7 @@
 import { UnknownLedgerError } from "@domain/ledger"
 import { USDAmount, USDTAmount, WalletCurrency } from "@domain/shared"
 import Ibex from "@services/ibex/client"
-import { IbexError, UnexpectedIbexResponse } from "@services/ibex/errors"
+import { IbexError } from "@services/ibex/errors"
 
 export const getBalanceForWallet = async ({
   walletId,
@@ -18,7 +18,15 @@ export const getBalanceForWallet = async ({
       }
       return resp
     }
-    if (resp.balance === undefined) return new UnexpectedIbexResponse("Balance not found")
+    if (resp.balance === undefined) {
+      // IBEX omits `balance` for drained / never-funded accounts (per-account and
+      // bulk endpoints alike: absent means zero — verified in prod during the USDT
+      // cutover). Post-cutover, every migrated account's legacy USD wallet reads
+      // this way; returning an error here broke the admin API's wallets[].balance
+      // for all migrated accounts (the cash-wallet compat redirect only runs when
+      // client capabilities are in ctx, i.e. for app users — never for admin).
+      return currency === WalletCurrency.Usdt ? USDTAmount.ZERO : USDAmount.ZERO
+    }
     return resp.balance
   } catch (err) {
     return new UnknownLedgerError(err)
diff --git a/test/flash/unit/app/wallets/get-balance-for-wallet.spec.ts b/test/flash/unit/app/wallets/get-balance-for-wallet.spec.ts
index 4c7fe2680..92738907d 100644
--- a/test/flash/unit/app/wallets/get-balance-for-wallet.spec.ts
+++ b/test/flash/unit/app/wallets/get-balance-for-wallet.spec.ts
@@ -1,5 +1,5 @@
 import { getBalanceForWallet } from "@app/wallets/get-balance-for-wallet"
-import { USDTAmount, WalletCurrency } from "@domain/shared"
+import { USDAmount, USDTAmount, WalletCurrency } from "@domain/shared"
 import Ibex from "@services/ibex/client"
 
 jest.mock("@services/ibex/client", () => ({
@@ -35,4 +35,35 @@ describe("getBalanceForWallet", () => {
     expect(Ibex.getCryptoReceiveBalance).not.toHaveBeenCalled()
     expect(result).toBe(balance)
   })
+
+  // IBEX omits `balance` on drained / never-funded accounts (absent means zero —
+  // verified in prod during the USDT cutover). Post-cutover every migrated
+  // account's legacy USD wallet reads this way; it must resolve to zero, not an
+  // error (an error here broke admin-API wallets[].balance for all migrated
+  // accounts, since the compat redirect never runs in admin ctx).
+  it("treats a missing balance field as zero for USD (drained legacy wallet)", async () => {
+    jest.mocked(Ibex.getAccountDetails).mockResolvedValue({
+      id: "drained-usd-ibex-id",
+    } as never)
+
+    const result = await getBalanceForWallet({
+      walletId: "drained-usd-ibex-id" as WalletId,
+      currency: WalletCurrency.Usd,
+    })
+
+    expect(result).toBe(USDAmount.ZERO)
+  })
+
+  it("treats a missing balance field as zero for USDT", async () => {
+    jest.mocked(Ibex.getAccountDetails).mockResolvedValue({
+      id: "drained-usdt-ibex-id",
+    } as never)
+
+    const result = await getBalanceForWallet({
+      walletId: "drained-usdt-ibex-id" as WalletId,
+      currency: WalletCurrency.Usdt,
+    })
+
+    expect(result).toBe(USDTAmount.ZERO)
+  })
 })