# Plugging a Bank Reconciliation: Why It Backfires

- Author: PreciseBankFlow (https://www.precisebankflow.com)
- Published: 2025-08-22
- Updated: 2025-08-22
- Category: Finding reconciliation errors
- Canonical: https://www.precisebankflow.com/blog/plugging-a-bank-reconciliation

> What plugging a bank reconciliation hides, how auditors spot plugs, why they compound month after month and how to unwind one already in the books.
Plugging a bank reconciliation means forcing the two balances to agree with an unexplained adjustment instead of finding the cause of the difference. The reconciliation looks finished, but the error is still in the books, and next month's differences pile onto it. Auditors look for plugs, and unwinding one means tracing each month's piece back to its source.

## What does plugging a bank reconciliation hide?

A plug is an entry or a reconciling line whose only purpose is to make the adjusted bank balance equal the adjusted book balance. It has no source document. Plugging a bank reconciliation hides the real reason for the difference, which can be anything from a missed fee to a stolen deposit.

Plugs take a few common forms:

- A journal entry to a suspense, miscellaneous or "reconciliation adjustment" account for the exact difference.
- A line on the reconciliation labelled "other" or "unreconciled" that is carried forward each month.
- An edit to a cleared amount so the totals agree.
- In some accounting software, an automatic adjustment entry accepted at the end of the reconcile screen.

### Plugs that software makes for you

Accounting software can create a plug without anyone choosing the word. When the reconcile screen shows a difference and offers to post an adjustment so the reconciliation can be finished, accepting it books an entry for the exact gap. The entry looks official because the system made it, and it often lands in an expense account where nobody will question it. Treat any such adjustment as a plug until someone has found what it represents. If your software allows it, restrict who can accept adjustments, so the preparer cannot quietly close a month that does not agree.

### What every form of plug has in common

Each one leaves the cause untouched. A missed bank charge stays missed. A deposit recorded twice stays doubled. The plug simply moves the error from the cash account into another account, where it is less likely to be looked at. The cause may be ordinary or serious, and the plug makes them look the same.

## How a reconciliation plug compounds month after month

A reconciliation plug compounds because each month's new difference is added to the old ones. The plug account becomes a mixture of unrelated errors, some positive and some negative. The longer it runs, the harder it is to say what any part of the balance represents.

The table below shows an example of a plug account over six months. The figures are invented. Each month the preparer booked the unexplained difference to a plug account rather than finding it.

| Month | New unexplained difference | Plug booked | Plug account balance |
| --- | ---: | ---: | ---: |
| January | 42.10 | 42.10 | 42.10 |
| February | (315.00) | (315.00) | (272.90) |
| March | 18.55 | 18.55 | (254.35) |
| April | 1,200.00 | 1,200.00 | 945.65 |
| May | (6.40) | (6.40) | 939.25 |
| June | 260.00 | 260.00 | 1,199.25 |

Read the last column alone and you would think the business has a single error of about 1,200. In fact it has six, ranging from 6.40 to 1,200.00, in both directions. The February entry ran the other way and more than cancelled January, so the balance turned negative and stayed that way until April. April's 1,200.00 might be a missing deposit, which is an error that matters a great deal and is easy to trace in April and hard to trace in December.

The compounding has a second effect. Once a plug exists, each later reconciliation starts from a figure that already contains it. A new difference in a later month can be an old error resurfacing, a new error, or the plug being partly reversed by a correction somebody made elsewhere. Without the history, nobody can tell which.

## How do auditors spot a plug in a bank reconciliation?

Auditors spot plugs by looking for reconciling items without support. Every line on a reconciliation should trace to a document: a check register entry, a deposit slip, a bank statement line, a journal entry with backup. A line that traces only to "to balance" is the plug.

Signs a reviewer looks for:

- An account with a name like suspense, reconciliation adjustment or miscellaneous that moves every month by odd amounts.
- Reconciling items with vague descriptions, such as "difference" or "other".
- Amounts that are carried forward unchanged for many months.
- A reconciliation completed with an adjustment entry generated by the software.
- Adjusted balances that agree to the cent while the outstanding items list is out of date.

Auditors also reperform the reconciliation from the statement. If the auditor's adjusted bank balance differs from the client's, and the difference matches a reconciling line, that line was a plug. For confirmation of the bank balance itself, an auditor may also go to the bank directly, and [verifying a bank statement with the bank](/blog/verify-a-bank-statement-with-the-bank) covers that step.

## Plug versus documented write-off of a reconciliation difference

A documented write-off is not a plug. Both book a difference you could not explain, but a write-off follows a real search, stays within a set threshold, is described honestly, and is approved by someone other than the preparer. A plug skips the search and hides the entry.

The differences in practice:

| | Plug | Documented write-off |
| --- | --- | --- |
| Search for the cause | None, or brief | Recorded steps, with what was checked |
| Size | Any amount | Within a policy threshold |
| Description | Vague | States that it is an unexplained difference and what was searched |
| Approval | Preparer alone | Reviewer initials |
| Recurrence | Often monthly | Rare; a repeat triggers a new search |

A write-off of a few cents after a proper search is normal practice. A write-off of 1,200.00 after a glance is a plug with a better label. [Writing off an unreconciled difference](/blog/write-off-unreconciled-difference) sets out when a write-off is acceptable and what the support should say.

## Unwinding a bank reconciliation plug already in the books

Unwinding a plug means breaking its balance back into the monthly pieces, finding the real cause of each piece, and correcting the causes instead of the total. It is slow work, but it is the only way to know what the plug was hiding. Start with the largest pieces and the most recent months.

Steps:

1. **List every entry to the plug account** since it was opened, with dates and amounts. In the example, that is the six lines in the table.
2. **Pull the reconciliation and statement for each month** with a plug entry.
3. **Re-reconcile each month from the statement**, using the original ledger before the plug. Note every unmatched item.
4. **Match each unmatched item to the plug entry for that month.** The April 1,200.00 may turn out to be a customer deposit never recorded, or a transfer booked to the wrong bank account.
5. **Book a correcting entry for each cause** in the current open period, crediting or debiting the plug account and the real account, with a description of what was found.
6. **Write off what remains** only if it is small and the search is documented, with reviewer approval.
7. **Close the plug account** once its balance is zero, and remove the reconcile-screen permission that allowed automatic adjustments if that was the route.

Many of the leftover items will be old outstanding checks and deposits that should have cleared long ago. Those need their own treatment, and [cleaning up old reconciling items](/blog/clean-up-old-reconciling-items) covers aging, researching and clearing them.

### When the monthly records are missing

Unwinding is harder when old statements or reconciliation files cannot be found. Request the missing statements from the bank first; most banks can provide copies of past statements, though older ones may take time or carry a fee. Without the ledger detail behind a plug entry, you can still compare the bank's activity for the month with the ledger's cash activity, line by line, and list what differs. The pieces you cannot rebuild go into a documented write-off with the reviewer's approval, and the note should say which months could not be reconstructed and why.

If a single cause is large enough to matter to reports already issued, raise it with the person who owns the financial statements before booking the correction.

## When the plugged figure points to something worse than an error

Sometimes a plug hides theft or a false statement rather than a mistake. A preparer who is also taking money has every reason to plug the difference, and a plug account that grows steadily in one direction is a classic sign. Treat an unexplained, one-way plug as a fraud question until the causes are found.

Warning signs that go beyond ordinary error:

- The plug grows by similar amounts each month, always in the same direction.
- The person who books the plug also handles deposits or signs checks.
- Supporting statements are copies rather than originals downloaded from the bank.
- Unmatched items include deposits that the customer says were paid but the bank never received.

If the bank statement itself might have been altered, compare it with a copy obtained directly from the bank before relying on it. Keep the original plug entries and reconciliation files exactly as they are; a later investigation will need them.

[PreciseBankFlow](/) reads each statement line by line and marks a statement out of balance when it does not foot, never adjusting it to fit. Differences stay visible as exceptions with their evidence, which is the opposite of a plug.