diff --git a/src/libs/TransactionUtils/index.ts b/src/libs/TransactionUtils/index.ts
index c41e65cd11f3..79d2dd15db97 100644
--- a/src/libs/TransactionUtils/index.ts
+++ b/src/libs/TransactionUtils/index.ts
@@ -636,6 +636,22 @@ function hasValidModifiedAmount(transaction: OnyxEntry<Transaction> | null): boo
     return transaction?.modifiedAmount !== undefined && transaction?.modifiedAmount !== null && transaction?.modifiedAmount !== '';
 }
 
+/**
+ * Builds the optimistic transaction used when an IOU report is converted to an expense report.
+ *
+ * Expense reports store amounts with the opposite sign of IOU reports (see `getAmount`/`getConvertedAmount`),
+ * so `amount`, `modifiedAmount` and `convertedAmount` are negated to match the expense-report convention.
+ * Absent converted values are not added so they keep being derived from the amount.
+ */
+function getNegatedAmountTransaction(transaction: Transaction): Transaction {
+    return {
+        ...transaction,
+        amount: -transaction.amount,
+        modifiedAmount: hasValidModifiedAmount(transaction) ? -Number(transaction.modifiedAmount) : '',
+        ...(transaction.convertedAmount != null && {convertedAmount: -transaction.convertedAmount}),
+    };
+}
+
 function isCreatedMissing(transaction: OnyxEntry<Transaction>) {
     if (!transaction) {
         return true;
@@ -2991,6 +3007,7 @@ export {
     hasPendingRTERViolation,
     hasAnyPendingRTERViolation,
     hasValidModifiedAmount,
+    getNegatedAmountTransaction,
     allHavePendingRTERViolation,
     hasPendingUI,
     getWaypointIndex,
diff --git a/src/libs/actions/Policy/Policy.ts b/src/libs/actions/Policy/Policy.ts
index 909e7274448c..eb97c1360fc0 100644
--- a/src/libs/actions/Policy/Policy.ts
+++ b/src/libs/actions/Policy/Policy.ts
@@ -95,7 +95,7 @@ import * as PhoneNumber from '@libs/PhoneNumber';
 import * as PolicyUtils from '@libs/PolicyUtils';
 import {getCustomUnitsForDuplication, getMemberAccountIDsForWorkspace, goBackWhenEnableFeature, isControlPolicy, navigateToExpensifyCardPage} from '@libs/PolicyUtils';
 import * as ReportUtils from '@libs/ReportUtils';
-import {hasValidModifiedAmount} from '@libs/TransactionUtils';
+import {getNegatedAmountTransaction} from '@libs/TransactionUtils';
 import type {AvatarSource} from '@libs/UserAvatarUtils';
 import type {Feature} from '@pages/OnboardingInterestedFeatures/types';
 import * as PaymentMethods from '@userActions/PaymentMethods';
@@ -4461,11 +4461,7 @@ function createWorkspaceFromIOUPayment(
     const transactionsOptimisticData: Record<string, Transaction> = {};
     const transactionFailureData: Record<string, Transaction> = {};
     for (const transaction of reportTransactions) {
-        transactionsOptimisticData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = {
-            ...transaction,
-            amount: -transaction.amount,
-            modifiedAmount: hasValidModifiedAmount(transaction) ? -Number(transaction.modifiedAmount) : '',
-        };
+        transactionsOptimisticData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = getNegatedAmountTransaction(transaction);
 
         transactionFailureData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = transaction;
     }
diff --git a/src/libs/actions/Report/index.ts b/src/libs/actions/Report/index.ts
index d667f59fd4c1..832d521935ab 100644
--- a/src/libs/actions/Report/index.ts
+++ b/src/libs/actions/Report/index.ts
@@ -169,7 +169,7 @@ import {
 } from '@libs/ReportUtils';
 import {buildOptimisticSnapshotData, getCurrentSearchQueryJSON} from '@libs/SearchQueryUtils';
 import playSound, {SOUNDS} from '@libs/Sound';
-import {getAmount, getCurrency, hasValidModifiedAmount, isOnHold, recalculateUnreportedTransactionDetails, shouldClearConvertedAmount} from '@libs/TransactionUtils';
+import {getAmount, getCurrency, getNegatedAmountTransaction, isOnHold, recalculateUnreportedTransactionDetails, shouldClearConvertedAmount} from '@libs/TransactionUtils';
 import addTrailingForwardSlash from '@libs/UrlUtils';
 import Visibility from '@libs/Visibility';
 import {cacheAttachment, removeCachedAttachment} from '@userActions/Attachment';
@@ -6781,11 +6781,7 @@ function convertIOUReportToExpenseReport(iouReport: Report, policy: Policy, poli
     const transactionsOptimisticData: Record<string, Transaction> = {};
     const transactionFailureData: Record<string, Transaction> = {};
     for (const transaction of reportTransactions) {
-        transactionsOptimisticData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = {
-            ...transaction,
-            amount: -transaction.amount,
-            modifiedAmount: hasValidModifiedAmount(transaction) ? -Number(transaction.modifiedAmount) : '',
-        };
+        transactionsOptimisticData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = getNegatedAmountTransaction(transaction);
 
         transactionFailureData[`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`] = transaction;
     }
diff --git a/tests/actions/PolicyTest.ts b/tests/actions/PolicyTest.ts
index 848b12b86f2a..1cf620943c7d 100644
--- a/tests/actions/PolicyTest.ts
+++ b/tests/actions/PolicyTest.ts
@@ -11,10 +11,11 @@ import OnyxUpdateManager from '@src/libs/actions/OnyxUpdateManager';
 import {askToJoinPolicy, joinAccessiblePolicy} from '@src/libs/actions/Policy/Member';
 import * as Policy from '@src/libs/actions/Policy/Policy';
 import ONYXKEYS from '@src/ONYXKEYS';
-import type {Onboarding, PolicyJoinMember, PolicyReportField, Policy as PolicyType, Report, ReportAction, ReportActions, TransactionViolations} from '@src/types/onyx';
+import type {Onboarding, PolicyJoinMember, PolicyReportField, Policy as PolicyType, Report, ReportAction, ReportActions, Transaction, TransactionViolations} from '@src/types/onyx';
 import type {Participant} from '@src/types/onyx/Report';
 import createRandomPolicy from '../utils/collections/policies';
 import {createRandomReport} from '../utils/collections/reports';
+import createRandomTransaction from '../utils/collections/transaction';
 import getOnyxValue from '../utils/getOnyxValue';
 import * as TestHelper from '../utils/TestHelper';
 import type {MockFetch} from '../utils/TestHelper';
@@ -7093,5 +7094,54 @@ describe('actions/Policy', () => {
             apiWriteSpy.mockRestore();
             isIOUReportUsingReportSpy.mockRestore();
         });
+
+        it('should negate the converted transaction amounts on the optimistic data so the expense-report table total stays positive', async () => {
+            await Onyx.set(ONYXKEYS.SESSION, {email: ESH_EMAIL, accountID: ESH_ACCOUNT_ID});
+
+            const employeeAccountID = 400;
+            const iouReportOwnerEmail = 'employee@example.com';
+
+            const iouReport: Report = {
+                ...createRandomReport(1, undefined),
+                reportID: '900',
+                type: CONST.REPORT.TYPE.IOU,
+                ownerAccountID: employeeAccountID,
+                chatReportID: '901',
+                policyID: 'oldPolicyID',
+                currency: CONST.CURRENCY.USD,
+                total: 5000,
+            };
+
+            const transaction: Transaction = {
+                ...createRandomTransaction(900),
+                transactionID: 'transaction900',
+                reportID: iouReport.reportID,
+                amount: 5000,
+                modifiedAmount: '',
+                convertedAmount: 6000,
+            };
+
+            await Onyx.set(`${ONYXKEYS.COLLECTION.REPORT}${iouReport.reportID}`, iouReport);
+            await Onyx.set(`${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`, transaction);
+            await waitForBatchedUpdates();
+
+            const mockTranslate = ((key: string) => key) as unknown as Parameters<typeof Policy.createWorkspaceFromIOUPayment>[8];
+            Policy.createWorkspaceFromIOUPayment(iouReport, undefined, ESH_ACCOUNT_ID, ESH_EMAIL, iouReportOwnerEmail, undefined, CONST.CURRENCY.USD, undefined, mockTranslate, {});
+            await waitForBatchedUpdates();
+
+            // Optimistic merge: read the stored transaction from Onyx
+            const optimisticTransaction: OnyxEntry<Transaction> = await new Promise((resolve) => {
+                const connection = Onyx.connect({
+                    key: `${ONYXKEYS.COLLECTION.TRANSACTION}${transaction.transactionID}`,
+                    callback: (value) => {
+                        Onyx.disconnect(connection);
+                        resolve(value);
+                    },
+                });
+            });
+
+            expect(optimisticTransaction?.amount).toBe(-5000);
+            expect(optimisticTransaction?.convertedAmount).toBe(-6000);
+        });
     });
 });
diff --git a/tests/actions/ReportTest.ts b/tests/actions/ReportTest.ts
index 5c99b6d11603..4f328b095867 100644
--- a/tests/actions/ReportTest.ts
+++ b/tests/actions/ReportTest.ts
@@ -4070,6 +4070,7 @@ describe('actions/Report', () => {
                 reportID: iouReport.reportID,
                 amount: 5000,
                 modifiedAmount: 6000,
+                convertedAmount: 6000,
             };
 
             await Onyx.merge(ONYXKEYS.PERSONAL_DETAILS_LIST, {
@@ -4097,6 +4098,7 @@ describe('actions/Report', () => {
             });
             expect(updatedTransaction?.amount).toBe(-5000);
             expect(updatedTransaction?.modifiedAmount).toBe(-6000);
+            expect(updatedTransaction?.convertedAmount).toBe(-6000);
         });
 
         it('should convert IOU report to expense report with correct policyID when reportTransactions are provided', async () => {