Ostium to Reopen Trading July 23 After $23.8M Vault Exploit

Ostium, a perpetuals trading protocol on Arbitrum, said it will reopen trading on Thursday, one week after an exploit drained its liquidity provider vault.

The reopening follows what the company described as a July 15 attack that took almost 23.8 million USDC from its liquidity provider (LP) vault. Ostium said the attacker compromised off-chain infrastructure feeding prices into the protocol, then submitted manipulated price reports to open and instantly close large positions and extract an artificial profit.

The company said trader collateral sits in a separate, isolated contract and was not affected, with positions remaining open.

Ostium said it paused trading and froze all trading contracts within 60 minutes of the first exploit transaction. It said it is working with Mandiant, zeroShadow, Collisionless, and SEAL 911 alongside law enforcement, and coordinating with exchanges, bridges, and stablecoin issuers.

Positions Carry Over

At reopen, open positions and pending orders will carry over, and positions will be marked to the live market price at that moment rather than to price movements during the pause, the company said. A position will be liquidated only if it is below its liquidation level at the reopening price. Take-profit, stop-loss, or limit orders whose levels have been reached at the live prices at 10:00 a.m. ET on July 23 will execute then. Ostium said traders have 24 hours before reopen to manage their positions.

The protocol will enable actions in stages, starting with protective and reduce-only actions such as closing positions, topping up collateral, and liquidations, followed by opening new positions once pending orders clear.

New OLP deposits remain paused, which Ostium said is designed so that existing liquidity providers who stay continue to earn a share of protocol revenue on a smaller capital base. Withdrawals will process at the next settlement. The company said it will provide further recovery details, including the structure and allocation of a capital commitment, in a follow-on post.

Ostium held about $37.8 million in total value locked as of Tuesday, all on Arbitrum.

The company also warned that illegitimate accounts are attempting to impersonate it and its team. Ostium said it is not circulating recovery forms and will never ask for private keys, seed phrases, or funds, and told users to trust only its official channels.