Coinbase Cold Storage: 99% Claim After $6.3B Binance Hack
Coinbase cold storage now holds over 99% of customer assets, the exchange said on November 4, a week after Binance lost about $6.3 billion. Per The Block, Coinbase also said the Binance breach did not affect it.
What Coinbase said about its cold storage
The Block reports that a Coinbase blog post lists distributed private keys, withdrawal limits and anomaly detection as its guards against unauthorized transfers. It says customer assets are held 1:1, stay customer property, and are not lent or used without authorization. Crypto.news adds that Coinbase describes key sharding, rate limits on cold-to-hot transfers and an emergency stop.
This is a company claim. Nobody outside Coinbase has verified the percentage. Coinbase’s own FY2025 10-K says it generally seeks to hold no more than 2% of custodied assets in hot wallets, and it warns it cannot promise its wallets will never be compromised.
Where Binance stands versus Coinbase cold storage
Per The Block, Binance was exploited on October 29 and says hackers used a fake job interview and an internal AI tool. On Wednesday it said it had replenished about 98% of the affected assets. It is buying the rest through market and over-the-counter channels, which is slower. It also widened Proof of Reserves to 44 tokens from 10.
Earlier coverage: the fake-job interview and the withdrawals that reopened.
Miner math: what exchange fear means for your margin
Here is the live maths on November 4. Bitcoin is $80,468 and the network is 1020 EH/s, so hashprice is about $35.71 per petahash per day. That is what one PH/s of hashing earns before power.
| Machine | 5c/kWh | 8c/kWh | 12c/kWh | Break-even |
|---|---|---|---|---|
| Antminer S19 (95 TH/s, 3250 W) | -$0.51 | -$2.85 | -$5.97 | 4.3c |
| Antminer S19k Pro (115 TH/s, 2645 W) | $0.93 | -$0.97 | -$3.51 | 6.5c |
| Antminer S19 XP (141 TH/s, 3010 W) | $1.42 | -$0.74 | -$3.63 | 7.0c |
| Antminer S21 Pro (234 TH/s, 3510 W) | $4.14 | $1.62 | -$1.75 | 9.9c |
Numbers are profit per day after electricity, at the three power prices shown. Break-even is the most you can pay per kilowatt-hour before the machine loses money. Specs are the manufacturer ratings; network data comes from mempool.space. Try your own power price in our free bitcoin mining profit calculator. See what these machines really sold for in our used ASIC miner price index. Want to run the same numbers on a machine you can buy today? See our used ASIC miners, or buy several at once through bulk lots.
If exchange-safety fears push bitcoin down 5%: the break-even power price on an S19k Pro falls from 6.5 to 6.1 cents per kilowatt-hour. At 8 cents, daily profit goes from -$0.97 to -$1.18.
The blunt answer for miners
Cold storage does not change difficulty or the block reward. A statement from Coinbase moves no hashprice by itself. Hashrate sits near 1020 EH/s per mempool.space, and your margin still depends on bitcoin’s price and your power rate. We read this as marketing at a moment when users are nervous. It is worth taking seriously only if the numbers get audited.
If the table above shows your S19 losing money at your power price, see our we buy used miners page or the mining economics guides.
-Nick
ING Mining
This is general information, not financial advice. Crypto is volatile, and exchanges can fail. Please do your own research.
How this story was made: drafted with the help of AI tools from public sources, then edited by Nick Squires. See our editorial policy. Spot an error? Email ns@ingmining.com.