These two get used interchangeably and they are not the same exercise. The confusion is expensive, because a seller can hand a buyer a year of clean bank reconciliations and the buyer can still be looking at overstated revenue.
The short version
| Bank reconciliation | Proof of cash | |
|---|---|---|
| Question it answers | Does the ledger balance agree with the bank balance? | Does the money that actually moved match what the company reported? |
| Who performs it | The company’s own bookkeeper | The buyer’s or lender’s diligence provider, independently |
| Period | One month, one account | The full diligence period, every account, month by month |
| Reconciles to | The general ledger cash account | The income statement and the tax return |
| Purpose of a difference | Something to clear | Something to investigate |
| Typical output | A cleared reconciliation | A schedule plus an exception list |
Why clean reconciliations prove less than people think
A bank reconciliation is a closed loop. It asks whether the cash account in the ledger agrees with the statement, and it is satisfied when the two tie. It does not ask whether the revenue line is real.
Consider a business that records a large customer deposit as revenue in March. The cash arrived, the ledger records it, the bank shows it, the reconciliation ties. Whether that money was revenue, a deposit against future work, a loan from the owner, or a transfer from another account the owner controls is a question the reconciliation never asks. Only the second exercise does.
That is why transfers, owner activity, merchant settlement and cut-off are where diligence findings live, and why none of them show up in a month-end close.
The three-way tie
The defining feature of a proof of cash is that it reconciles in three directions rather than one: bank to income statement, bank to tax return, and month to month across the full period. The tax return matters because it is the one statement the seller filed under penalty of perjury. Where the management profit and loss flatters the return, that gap is the finding, and the buyer is usually being asked to pay a multiple of the flattering number.
When each one is the right tool
If you are closing the books each month and want to know your cash balance is right, a bank reconciliation is exactly the correct procedure and a proof of cash would be overkill.
If you are buying a business, lending against one, or selling one and want the numbers to survive a buyer’s scrutiny, a reconciliation is not sufficient and never was. From October 1, 2026, that is no longer only a matter of judgment for a class of transactions: SBA acquisitions at $3 million or more require a quality of earnings report containing a cash proof.
One practical implication for tooling: general accounting reconciliation software is built for the first job. It is not built to reconcile to a tax return, to hold an exception queue for a reviewer, or to produce something a credit committee can audit. More on that in how to evaluate proof of cash software.
Get in touch to scope a proof of cash, or see what one costs.