Auditing Firm Mazars Pauses Proof-of-Reserves Work for Crypto Clients

Mazars said it had concerns about how the reports were understood by the public.

AccessTimeIconDec 16, 2022 at 10:12 a.m. UTC
Updated May 9, 2023 at 4:04 a.m. UTC

Mazars, the auditing firm working with Binance and other crypto exchanges, has paused work on proof-of-reserves reports for crypto clients, Binance said in an emailed statement and Mazars confirmed to CoinDesk.

"Mazars has indicated that they will temporarily pause their work with all of their crypto clients globally, which include, KuCoin and Binance. Unfortunately, this means that we will not be able to work with Mazars for the moment," a Binance spokesperson said. The suspension was reported earlier by Bloomberg.

Mazars said in an emailed statement that it had paused only its crypto work relating to proof-of-reserves reports. "This is due to concerns regarding the way these reports are understood by the public," the company said.

Mazars added that proof-of reserve reports "do not constitute either an assurance or an audit opinion on subject matter. Instead they report limited findings based on the agreed procedures performed on the subject matter at a historical point in time."

The accounting firm performed a proof-of-reserves assessment of Binance earlier this month, finding its bitcoin reserves were overcollateralized.

The auditor also found that Kucoin's BTC, ETH, USDT and USDC reserves were all overcollateralized. Mazars' assessment of's reserves found them to be fully backed 1:1.

Mazars' reports on Binance and KuCoin were removed from its website, though they are available online at SilverSixpence, which assisted in their production.

Crypto exchanges came under pressure to provide proof of reserves in the wake of the of collapse of FTX, a once-dominant exchange that went bankrupt last month. Former CEO Sam Bankman-Fried is now in custody in the Bahamas on charges of wire fraud and conspiracy to commit money laundering, among others.

Binance coin (BNB) fell after the announcement. It has lost about 5% in the past 24 hours, CoinDesk data shows.'s CRO has lost 3.9% and KuCoin's native token KCS around 2.5%.

UPDATE (Dec. 16, 12:35 UTC): Adds price performance of Binance's BNB token,'s CRO and Kucoin's KCS.

UPDATE (Dec. 16, 16:58 UTC): Adds confirmation and comments from Mazars.

UPDATE (Jan. 9, 09:12 UTC): Changes headline and first paragraph to clarify that Mazars has specifically paused proof-of-reserve work for crypto clients; adds that Binance and KuCoin reports are available online.


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Jamie Crawley

Jamie Crawley is a CoinDesk news reporter based in London.