Proof-of-reserves: useful, but not a guarantee

What proof-of-reserves is trying to do

After FTX collapsed, customers asked an obvious question: 'how do we know an exchange actually has the coins it claims to be holding for us?' The answer the industry came up with is called proof-of-reserves. The basic idea is that the exchange points to on-chain wallets containing customer assets and publishes a cryptographic summary of customer balances. Anyone can check that the wallets exist and contain the claimed amount, and individual customers can usually verify that their own balance was included.

When this is done well, it's genuinely useful. You can see, on-chain, that the exchange controls real wallets containing real coins. You can confirm your own balance is part of the total. That's more than customers had in 2022.

Here's where you have to read carefully. Proof-of-reserves usually only proves assets — that the exchange has X. It does not necessarily prove liabilities — what the exchange owes. An exchange could hold a billion dollars of crypto and still be insolvent if it owes two billion. A proper proof should pair reserves with liabilities so you can compare. Without that pairing, you have half a balance sheet.

Other things to watch for. Snapshot timing — a reserve report is a photograph of a single moment. An exchange can briefly borrow assets to look strong on the day of the snapshot. Ongoing or continuous attestations are stronger than annual ones. Custody address — the report should show wallets the exchange actually controls, with signatures proving control. And the auditor — a real third-party accounting firm doing the attestation is meaningfully different from the exchange publishing its own numbers.

The honest summary: proof-of-reserves is a step forward. It is not, on its own, a guarantee. Treat it as one input. Combine it with operational signals — withdrawal speed, support quality, public disclosures — and your own sizing rules. The goal isn't certainty, it's not being a creditor when something breaks.

Recap: proof-of-reserves shows assets, usually not liabilities. Read it as one signal of many, not as proof of solvency.