diff --git a/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.test.tsx b/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.test.tsx
new file mode 100644
index 000000000..01ef1102b
--- /dev/null
+++ b/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.test.tsx
@@ -0,0 +1,102 @@
+import '@testing-library/jest-dom'
+import type { TTransaction } from '6-shared/types'
+import { configureStore } from '@reduxjs/toolkit'
+import { render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import React from 'react'
+import { Provider } from 'react-redux'
+import i18n from 'i18next'
+import { beforeAll, describe, expect, test, vi } from 'vitest'
+import dataReducer from 'store/data'
+import { trModel } from '5-entities/transaction'
+import { BulkEditModal } from './BulkEditModal'
+
+beforeAll(async () => {
+  await i18n.changeLanguage('en')
+})
+
+const makeTr = (id: string, comment: string | null): TTransaction =>
+  trModel.makeTransaction({
+    id,
+    user: 0,
+    date: '2022-10-20',
+    incomeInstrument: 2,
+    incomeAccount: 'acc1',
+    outcomeInstrument: 2,
+    outcomeAccount: 'acc1',
+    outcome: 100,
+    comment,
+  })
+
+const createTestStore = (transactions: TTransaction[]) =>
+  configureStore({
+    reducer: { data: dataReducer },
+    preloadedState: {
+      data: {
+        current: {
+          serverTimestamp: 0,
+          instrument: {},
+          country: {},
+          company: {},
+          user: {},
+          merchant: {},
+          account: {},
+          tag: {},
+          budget: {},
+          reminder: {},
+          reminderMarker: {},
+          transaction: Object.fromEntries(transactions.map(tr => [tr.id, tr])),
+        },
+      },
+    },
+  })
+
+const getComment = (store: ReturnType<typeof createTestStore>, id: string) =>
+  store.getState().data.current.transaction[id].comment
+
+const commentField = () => screen.getByRole('textbox')
+const saveButton = () => screen.getByRole('button', { name: 'Apply Changes' })
+
+/**
+ * The modal lives permanently in the tree and gets ids only when the user
+ * selects transactions, so tests open it the same way the app does.
+ */
+const renderAndOpen = (
+  store: ReturnType<typeof createTestStore>,
+  ids: string[]
+) => {
+  const modal = (props: { ids: string[]; open: boolean }) => (
+    <Provider store={store}>
+      <BulkEditModal {...props} onClose={vi.fn()} onApply={vi.fn()} />
+    </Provider>
+  )
+  const { rerender } = render(modal({ ids: [], open: false }))
+  rerender(modal({ ids, open: true }))
+}
+
+describe('BulkEditModal', () => {
+  test('shows the current comment of the selected transaction', () => {
+    const store = createTestStore([makeTr('tr1', 'Old comment')])
+    renderAndOpen(store, ['tr1'])
+    expect(commentField()).toHaveValue('Old comment')
+  })
+
+  test('clears the comment when the field is emptied', async () => {
+    const store = createTestStore([makeTr('tr1', 'Old comment')])
+    renderAndOpen(store, ['tr1'])
+    await userEvent.clear(commentField())
+    await userEvent.click(saveButton())
+    expect(getComment(store, 'tr1')).toBe(null)
+  })
+
+  test('does not touch comments when the field is left untouched', async () => {
+    const store = createTestStore([
+      makeTr('tr1', 'One'),
+      makeTr('tr2', 'Another'),
+    ])
+    renderAndOpen(store, ['tr1', 'tr2'])
+    await userEvent.click(saveButton())
+    expect(getComment(store, 'tr1')).toBe('One')
+    expect(getComment(store, 'tr2')).toBe('Another')
+  })
+})
diff --git a/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.tsx b/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.tsx
index 38bcb2682..755dd540e 100644
--- a/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.tsx
+++ b/src/3-widgets/transaction/TransactionList/TopBar/BulkEditModal.tsx
@@ -39,23 +39,26 @@ export const BulkEditModal: FC<BulkEditModalProps> = ({
   const types = getTypes(transactions)
   const tagType = types.income ? (types.outcome ? null : 'income') : 'outcome'
   const commonTags = sameTags ? transactions[0]?.tag || [] : ['mixed']
+  const commonComment = sameComments ? transactions[0]?.comment || '' : ''
 
   const [tags, setTags] = useState(commonTags)
-  const [comment, setComment] = useState(
-    sameComments ? transactions[0]?.comment || '' : ''
-  )
+  const [comment, setComment] = useState(commonComment)
 
   useEffect(() => {
-    if (open) setTags(commonTags)
+    if (open) {
+      setTags(commonTags)
+      setComment(commonComment)
+    }
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [setTags, ids, open])
+  }, [setTags, setComment, ids, open])
 
   const onSave = () => {
     const opts = {
       tags: equalArrays(commonTags, tags) ? undefined : tags,
-      comment,
+      // An empty comment is a valid change, so untouched means `undefined`
+      comment: comment === commonComment ? undefined : comment,
     }
-    if (opts.tags || opts.comment) {
+    if (opts.tags || opts.comment !== undefined) {
       dispatch(trModel.bulkEditTransactions(ids, opts))
     }
     onApply()
diff --git a/src/5-entities/transaction/thunks.test.ts b/src/5-entities/transaction/thunks.test.ts
new file mode 100644
index 000000000..684a69495
--- /dev/null
+++ b/src/5-entities/transaction/thunks.test.ts
@@ -0,0 +1,72 @@
+import type { TTransaction } from '6-shared/types'
+import { configureStore } from '@reduxjs/toolkit'
+import { describe, expect, test } from 'vitest'
+import dataReducer from 'store/data'
+import { makeTransaction } from './makeTransaction'
+import { bulkEditTransactions } from './thunks'
+
+const makeTr = (comment: string | null): TTransaction =>
+  makeTransaction({
+    id: 'tr1',
+    user: 0,
+    date: '2022-10-20',
+    incomeInstrument: 2,
+    incomeAccount: 'acc1',
+    outcomeInstrument: 2,
+    outcomeAccount: 'acc1',
+    outcome: 100,
+    tag: ['tag1'],
+    comment,
+  })
+
+const createTestStore = (tr: TTransaction) =>
+  configureStore<{ data: ReturnType<typeof dataReducer> }, any>({
+    reducer: { data: dataReducer },
+    preloadedState: {
+      data: {
+        current: {
+          serverTimestamp: 0,
+          instrument: {},
+          country: {},
+          company: {},
+          user: {},
+          merchant: {},
+          account: {},
+          tag: {},
+          budget: {},
+          reminder: {},
+          reminderMarker: {},
+          transaction: { [tr.id]: tr },
+        },
+      },
+    },
+  })
+
+const getComment = (store: ReturnType<typeof createTestStore>) =>
+  store.getState().data.current.transaction.tr1.comment
+
+describe('bulkEditTransactions', () => {
+  test('sets a comment', () => {
+    const store = createTestStore(makeTr(null))
+    store.dispatch(bulkEditTransactions(['tr1'], { comment: 'New comment' }))
+    expect(getComment(store)).toBe('New comment')
+  })
+
+  test('clears a comment when an empty string is passed', () => {
+    const store = createTestStore(makeTr('Old comment'))
+    store.dispatch(bulkEditTransactions(['tr1'], { comment: '' }))
+    expect(getComment(store)).toBe(null)
+  })
+
+  test('keeps the comment when it is not passed', () => {
+    const store = createTestStore(makeTr('Old comment'))
+    store.dispatch(bulkEditTransactions(['tr1'], { tags: ['tag2'] }))
+    expect(getComment(store)).toBe('Old comment')
+  })
+
+  test('supports the $& placeholder for the previous comment', () => {
+    const store = createTestStore(makeTr('Old comment'))
+    store.dispatch(bulkEditTransactions(['tr1'], { comment: '$& and more' }))
+    expect(getComment(store)).toBe('Old comment and more')
+  })
+})
diff --git a/src/5-entities/transaction/thunks.ts b/src/5-entities/transaction/thunks.ts
index a7d34ef1a..e8fb9ea7e 100644
--- a/src/5-entities/transaction/thunks.ts
+++ b/src/5-entities/transaction/thunks.ts
@@ -144,8 +144,9 @@ const modifyTags = (prevTags: string[] | null, newTags?: string[]) => {
   return result
 }
 const modifyComment = (prevComment: string | null, newComment?: string) => {
-  if (!newComment) return prevComment
-  return newComment.replaceAll('$&', prevComment || '')
+  // Only an omitted comment means "keep the old one". An empty string clears it.
+  if (newComment === undefined) return prevComment
+  return newComment.replaceAll('$&', prevComment || '') || null
 }
 
 function split(raw: TTransaction) {