OKX reported 139,865 BTC in customer account assets in its 47th consecutive proof-of-reserves report, a 4.07% rise from the Aug. 11 snapshot. The exchange lists $27.4 billion in primary assets overall, based on a Sept. 8 snapshot date.
The comparison comes from the exchange’s monthly snapshot series. In August the same ledger showed 134,399 BTC in user account assets. The September figure adds 5,466 BTC, the largest single increase of the three assets the exchange tracks in the report.
Every asset in the report moved up
Customer ether balances rose 3.49% between the two snapshots, from about 1.726 million ETH to 1.786 million ETH. USDT holdings climbed 4.62% to 8.49 billion tokens. All three assets highlighted gained, a pattern worth noting because it runs against the flow elsewhere in the sector.
Recent exchange-level data has mostly shown one cohort moving one way and the other cohort moving the other way. Network data for this week recorded about 24,000 BTC leaving exchanges in a single day, the largest net withdrawal since March, which branching analytics firms tend to read as holders moving coins to cold storage rather than selling pressure. Whale stablecoin deposits to Binance jumped 40% in the same window, a blend that has historically preceded periods of elevated volatility. Against that backdrop, a single venue reporting simultaneous growth in user bitcoin, ether and stablecoin balances suggests some of those coins were moving toward a venue rather than out of the system entirely.
The Bitcoin reserve ratio moved from 111% in August to 109% in September. The drop is arithmetic, not a warning sign. New customer deposits grew faster than the exchange’s own wallet assets over the period, so the two sides of the ratio moved at different speeds.
Against the 139,865 BTC held by users, OKX listed 153,151 BTC in controlled wallet assets. That total splits into 146,359 BTC under the exchange’s own custody and 6,792 BTC with third-party custodians. Anything above 100% means the venue holds more than enough to cover customer claims, at least as measured at the snapshot date. The ratio has stayed above 100% for the entire reporting series.
How the audit holds up
OKX publishes zk-STARK proofs alongside the wallet addresses it lists. Users can download the proof database and confirm their own balance is included in the dataset without trusting a third party to check for them. zk-STARKs are a class of cryptographic proof that lets a verifier confirm a computation was done correctly without seeing the underlying data. In this case the computation is the sum of all customer balances and the underlying data is the exchange’s internal ledger. The system is the same one the exchange has run since the reports began, and the 47th edition keeps the chain unbroken month to month.
Proof-of-reserves of this kind is voluntary rather than mandatory in most jurisdictions. After the collapse of FTX and several other exchanges in late 2022, many large venues committed to monthly or quarterly attestations, though formats and rigor vary widely between firms. Some venues rely on external audit firms, some use Merkle-tree proofs with manual snapshot pages, and some do both. The common criticism is that most variants prove the exchange side of the ledger in detail while saying nothing about liabilities that sit outside the snapshot, such as loans made against collateral or obligations owed to counterparties that are not on the platform at that moment.
The gap got partially narrower this year. Regulators in several markets started asking exchanges for more granular reporting than a plain snapshot, including breakouts of what each asset class is actually used for behind the scenes. The CFTC moved ahead with proposed regulations for leveraged crypto trading on registered venues, and the SEC approved rule changes that opened the door to triple-leveraged bitcoin ETFs. More venues are expected to follow the format OKX is using here as rules firm up on what an attestation should actually cover.
Why every number in the report needs care
User balance growth on a single exchange is not the same as market-wide demand. The gains could be split across many small traders, a handful of larger ones, or one big desk that parked assets for internal purposes and does not intend to trade them soon. Proof-of-reserves by design proves the exchange side of the ledger, not who the users are or why they moved coins. Reading it as a demand signal has burned traders before when a single large account rebalanced.
The report also lands as bitcoin holds in the low $83,000 range after a week where liquidations and ETF buying pulled the price in opposite directions. Spot bitcoin ETFs in the US took in about $119 million net on Tuesday while ether funds bled roughly $202 million that same day, mostly from one large ETF. Weekly cross-asset flows for all crypto ETFs came in near $2.39 billion, enough to push 2026 net flows back above zero despite a 4.3% weekly drop in the bitcoin price. Balances rising while the price drifts sideways implies accumulation rather than chase behavior.
The next monthly snapshot will show whether the deposit pace kept up. If user balances fall back toward August levels while the price holds flat, the September jump looks like a timing artifact. If they keep climbing, that points to a steady shift in where holders keep their coins. Either way, the reserve ratio has room to fall and still stay above 100%, so a narrow miss next month would not signal a solvency problem.