Crypto Exchanges Publish Cold Storage Ratios After Binance Wallet Attack

Cold storage figures are becoming a public measure of exchange security after an attack on Binance’s hot wallet infrastructure. Several exchanges have responded by publishing the share of assets they say they keep offline, giving customers a clearer view of how funds are distributed. The disclosures answer a practical question: how much customer crypto is exposed to systems designed for frequent transactions? They don’t show whether those systems, or the people who control them, can withstand an attack.

Exchanges disclose their asset splits

Gate on Thursday launched a “Proof of Security” (PoSEC) framework. It reported that 88.26% of its total assets are in cold storage and 11.74% in hot wallets. Gate says its cold holdings could cover 104.58% of customer assets if its hot wallets were drained entirely. That figure is presented as a coverage claim under a specific scenario; customers still need to understand what assets and liabilities the calculation includes.

“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. It added that a third-party audit firm is still reviewing the data. That review matters because a published ratio is only as useful as the definitions and records behind it. Until the review is complete, the framework offers a snapshot from the exchange rather than a finished, independently checked account.

Coinbase said in a Wednesday post that it keeps more than 99% of customer assets in offline cold storage and regularly moves excess assets into cold storage. The company framed the disclosure as a response to customers asking how it would guard against an incident like Binance’s. The emphasis on moving excess assets suggests that wallet balances can change as operational needs shift. A ratio, then, is a view of asset placement, not a promise that every asset stays in one category at all times.

Upbit, South Korea’s largest cryptocurrency exchange, reported that 99.17% of its assets were in cold wallets and 0.83% in hot wallets as of September 2026. The figures have been disclosed to the Financial Supervisory Service. Unlike a general claim about security, this split gives a dated reference point. It still leaves open how frequently the balance changes and what procedures govern transfers between wallet types.

“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 parent Dunamu told Cointelegraph. The spokesperson said Upbit’s cold wallet share was the highest among South Korea’s five major KRW-based exchanges and above the 80% regulatory minimum, responding to South Korea’s call for exchanges to increase their cold storage ratios. A target below 1% gives the policy a concrete threshold, but it doesn’t describe the controls that govern the remaining hot wallet balance. This is more significant than it looks: customers can compare stated practices, while the security of the underlying process remains harder to inspect.

Reported figures need context

Other major South Korean exchanges reported lower cold wallet shares at the end of September, according to Financial Supervisory Service figures cited in earlier reporting: Bithumb at 94.76%, Coinone at 85%, Digital X, formerly Korbit, at 82.79%, and GOPAX at 80.54%. Those figures show that reported practices vary across the market, even among exchanges operating under the same broad national framework. They don’t, by themselves, establish that an exchange with a higher cold storage share is safer. The mix can reflect operational choices as well as security policy.

OKX’s security overview, last updated Sept. 18, 2026, says more than 95% of client crypto assets are held in cold wallets, with less than 5% in hot wallets. That disclosure gives customers a broad sense of how the company separates assets used for ongoing activity from those kept offline. It doesn’t tell readers whether the figures are calculated in the same way as those published by Gate, Coinbase or Upbit.

These percentages don’t necessarily measure the same thing: exchanges use different reporting periods and may calculate their cold storage shares against different asset bases. The figures are useful disclosures, but they don’t support a simple ranking of security. A meaningful comparison would need consistent definitions, dates and information about how each exchange verifies the underlying balances. Without those details, a decimal point can create an impression of precision that the disclosures may not support.

Cold storage is only one security measure

TRM Labs estimated that attackers stole approximately $6.36 billion from Binance’s hot wallet infrastructure last week, with most of the funds taken in about 20 minutes. Binance CEO Richard Teng said the “vast majority” of user assets are held in cold wallets, but Binance has not published a precise split. The incident puts the central limitation of these disclosures in sharp focus: a large offline reserve may limit the portion exposed to a hot wallet attack, but it can’t explain how the compromised systems were reached or how quickly an exchange can respond.

Even assets kept offline can be at risk if signing systems are compromised, access controls fail or employees approve fraudulent transactions. Cold storage describes how a wallet is connected to networks; it doesn’t make the surrounding process invulnerable. Hong Kong’s Securities and Futures Commission warned in an August 2025 circular that weaknesses of this kind could expose both hot and cold wallet infrastructure. The warning points to a broader lesson: wallet security depends on the systems and decisions that control access, as well as where keys are stored.

What customers can learn from the disclosures

For customers, the disclosures provide a useful starting point for assessing how exchanges manage assets. If you're working in this space, the figures can help frame questions about wallet access, transfer approvals and independent review. The answers are harder to reduce to a percentage. (And this is the part most people overlook.)

The more meaningful test is whether published storage ratios sit alongside clear reporting and controls that protect the systems and people with access to those wallets. Customers should read a ratio as one piece of evidence, with attention to its date, scope and review status. Useful transparency. Limited assurance.

Related: Fed, OCC check US banks after Binance hack as experts flag security risks

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