Crypto exchanges disclose cold-storage ratios after Binance hack

Crypto exchanges are disclosing how they divide assets between offline cold storage and internet-connected hot wallets after an attack on Binance’s hot-wallet infrastructure last week.

Gate launched its “Proof of Security” framework Thursday and reported that 88.26% of its total assets were in cold storage, with 11.74% in hot wallets. The exchange said its cold-storage holdings could cover 104.58% of customer assets if its hot wallets were completely drained.

“By publicly disclosing the distribution of assets between platform cold storage and hot wallets, PoSEC provides visibility into asset storage structures and their ability to cover potential losses under extreme scenarios,” Gate said. The figures are being reviewed by an independent third-party audit firm.

Coinbase reported in a Wednesday blog post that more than 99% of customer assets were held in offline cold storage. The exchange said it regularly transfers excess assets from hot wallets to cold storage. The post referred to customer concerns after the Binance incident.

Upbit, South Korea’s largest cryptocurrency exchange, reported Tuesday that 99.17% of its assets were in cold wallets and 0.83% were in hot wallets as of September 2026. The figures had already been disclosed to South Korea’s Financial Supervisory Service.

“Our aim is to keep our hot wallet holdings at an absolute minimum, with a target of maintaining them below 1% of customer digital assets,” a spokesperson for Upbit’s parent company, Dunamu, said. The company reported that Upbit had the highest cold-storage ratio among South Korea’s five major won-based cryptocurrency exchanges and exceeded the regulatory minimum of 80%.

Financial Supervisory Service figures from the end of September showed cold-storage ratios of 94.76% at Bithumb, 85% at Coinone, 82.79% at Digital X, formerly Korbit, and 80.54% at GOPAX. OKX’s security overview, last updated Sept. 18, 2026, reported that more than 95% of customer crypto assets were in cold wallets and less than 5% were in hot wallets.

The ratios are not directly comparable in every case because exchanges use different reporting dates and methods to calculate the share of assets in cold storage. Offline wallets can still be exposed through compromised signing systems, weak access controls or employees approving fraudulent transactions.

Threat actors stole approximately $6.36 billion from Binance’s hot-wallet infrastructure last week, most of it within about 20 minutes, according to TRM Labs. Binance CEO Richard Teng reported that the “vast majority” of user assets were held in cold wallets, but Binance has not published a precise split.

In an August 2025 circular, Hong Kong’s Securities and Futures Commission warned that weaknesses in wallet management could compromise both hot- and cold-wallet systems.

Reviewed and fact-checked by Alex Panasenko on November 6.