OKX

Its reserve proof is one of the better pieces of cryptography in this category and one of the weaker pieces of assurance, for the same reason: it is monthly and genuinely verifiable, and nobody independent has signed it. You can check the maths. You cannot check that the inputs were complete, which is exactly what an attesting firm is for.

Set against that is a 2025 guilty plea in a US federal court carrying over $504m in penalties for operating unlicensed for years. That is not a technical filing violation — it is an admission of having run the business outside the rules for an extended period, and it belongs in any assessment of what the company’s disclosures are worth.

We score custody 6 out of 10, mid-table. The proof is real and the plea is real, and neither cancels the other. What raises OKX above the venues at the bottom of this rating is that no customer funds have gone missing and the reserve reporting happens monthly rather than when convenient.

KYC and access score 5 out of 10, the weakest criterion here — the published limits and tier structure leave more unanswered than they should for a venue of this size.

A $10,000 bitcoin buy cost 0.10% on 14 July 2026, joint-cheapest in our rating, and the more interesting figure is what happened at ten times the size: 0.1005%. That is one of the flattest cost curves we measured, and it is a depth result rather than a pricing one.

We found 80.9 BTC within 0.1% of best ask — deeper than Bybit’s 62.2, behind Binance’s 142.0 and Kraken’s 189.8. Combined with the lowest fee tier, that makes OKX one of the genuinely cheap places to move size, and we score liquidity 9 out of 10.

API response latency measured 330 ms: mid-table, better than Binance’s 460 ms and KuCoin’s 465 ms, behind Coinbase and Kraken.

On execution alone OKX is among the best venues in this rating. Everything separating it from the top is in the section above, which is the trade it asks you to make.