Commingling of Client Funds
Mixing customer assets with a firm's own money, or with other customers' assets, so that ownership can no longer be cleanly separated.
Regulated brokers must keep customer property segregated from house property, with reconciliations proving that segregated assets at least equal what customers are owed. Digital-asset exchanges commonly pool deposits into omnibus wallets for operational efficiency, which is not inherently improper if internal records are accurate and reconciled, but it removes the on-chain evidence that would let a user verify their own claim. Harm occurs when pooled customer assets are used to fund house trading, to meet other customers' withdrawals, or to post collateral elsewhere. The 2022 failure of FTX is the reference case, where customer assets were not segregated from an affiliated trading firm's obligations.
In practice
Because an omnibus wallet holds one balance for many customers, an on-chain observer cannot tell whether it is fully backed, over-collateralized, or short.
The common misunderstanding
That coins deposited on an exchange remain legally yours, when pooled assets combined with terms granting the platform use rights can leave you an unsecured creditor rather than an owner.