https://techcrunch.com/2022/11/11/can-proof-of-reserves-prevent-future-crypto-exchange-collapses/

A number of crypto exchanges are rushing to publish proof-of-reserves in a seeming attempt to reassure investors their funds are safe as fellow exchange FTX melts down.

Proof-of-reserves (PoR) are independent audits by third parties that aim to provide transparency and evidence that a custodian holds the assets it claims to own on behalf of its clients. Auditors then aggregate balances into something called a Merkle tree, which entails all client balances.