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.
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.
