Ostium Review

How Ostium scores in perpetual DEXs

This entry rates Ostium's perpetuals venue on Arbitrum in our perpetual DEX ranking. Ostium lists mostly traditional markets, including stocks, commodities, indices and forex, alongside crypto. Trades settle on-chain in USDC at prices from its own oracle, and the net exposure is hedged off-chain with institutional partners. The OLP vault comes up only where it affects trader risk. The basis is desk research of Ostium's documentation, terms, GitHub and on-chain contract settings, checked on November 1, 2026. No account was opened and no trade was placed. The category uses five equally weighted criteria, each marked 0 to 10, as set out in our ratings methodology.

The overall score is the plain average: (8 + 8 + 9 + 10 + 8) ÷ 5 = 43 ÷ 5 = 8.6. That puts Ostium first of nine in the category, level on score with dYdX, which is listed after it under the alphabetical tie rule, and 0.2 points ahead of GMX. A re-check against current sources on November 1, 2026 left all five marks unchanged.

Strongest criteria: audits and code

Audit disclosure (10)

This is the only 10 for audit disclosure in the category. The audits page links six reports and gives the scope and main findings of each. Zellic reviewed the original contracts in February 2024 and the upgraded trading contracts in November 2025. ThreeSigma ran a second review from February 19 to March 22, 2024. Pashov Audit Group delivered reviews in January 2025, April 2025 and January 2026. The latest covered 13 core contracts in the new vault settlement design ahead of the April 2026 upgrade. It found one high-severity share-price accounting issue, which the page says was resolved before release. The record is dated, attributed and current with the deployed design, which is what the top mark requires. An Immunefi bug bounty is linked from the same page.

Licence & code openness (9)

The 0xOstium/smart-contracts-public repository is MIT-licensed. It holds the contracts the audits page lists as deployed, including the vault, trading, trading callbacks, price router, timelock and verifier, and its last release, v1.5.0, was merged in May 2026. The upgradeable contracts sit behind a ProxyAdmin. An on-chain read on November 1, 2026 showed it owned by a timelock with a minimum delay of 64,800 seconds (18 hours). The mark stops at 9 because the Python SDK and data repositories carry no licence, and the oracle and off-chain hedging services are not public code.

Criteria at 8: fees, liquidation and risk

Fee transparency (8)

The fee page lists four charges. The opening fee is 3 to 10 basis points of notional by pair, so a $10,000 position pays $3 to $10 to open. A $0.10 oracle fee is charged on each price request and refunded on a successful full close, capped at 10 USDC per transaction. An early-close fee falls from 40 bps to zero over 15 seconds and applies only to profitable closes, capped at the profit. There is no closing fee and no separate liquidation fee. Two points keep the mark at 8. Per-pair opening fees load live from the protocol's subgraph rather than sitting in a fixed table, and the rollover markup is given as a 1% to 2% range rather than per pair.

Funding & liquidation clarity (8)

Ostium has no funding payment between longs and shorts. A rollover fee accrues per block and is updated daily: the underlying asset's carry plus a 1% to 2% annual premium for longs, and the negative of the carry plus the premium for shorts. The carry comes from SOFR for stocks and indices and from the futures curve for commodities, forex and crypto, smoothed with a published Gaussian weighting. In the docs' oil example, shorts pay about 42% a year while longs collect about 38%. Liquidation uses one formula: the threshold is 100% minus leverage ÷ maximum pair leverage × 25%. At 20x on a 200x pair, liquidation comes at a 97.5% loss of collateral, about a 4.9% price move. Liquidation is less trader-friendly than it sounds, though. All remaining collateral is retained, and rollover moves the liquidation price closer over time. Combined with a carry method that is harder to reproduce than a standard funding formula, that is why the mark is 8 rather than the 9 or 10 given to dYdX, GMX, Orderly Network and Hyperliquid.

Risk documentation (8)

The vault page sets out the loss order. A junior buffer, posted by parties linked to Ostium and by strategic partners, absorbs trader profit and loss first, and OLP, the senior tranche, is hit only once the buffer is gone. The protocol page says this covers trading and hedging losses, not a security event, and that OLP deposits are not insured. It also states that a daily settlement moves USDC between the on-chain vault and the off-chain hedging book, so the system depends on partners settling their side. Liquidations are executed by Gelato keeper bots within seconds of the threshold, with no margin calls. The documentation does not give the buffer's target size in figures, which caps this mark at 8. Our guide to crypto risk management covers how leverage sets the distance to liquidation.

What the score does not cover

• Execution quality. Spreads, quote quality from hedging partners and fills outside market hours were not measured.
• Counterparty strength. The financial standing of the off-chain hedging partners is not assessed.
• OLP as an investment. Vault returns and withdrawal timing are outside this rating.
• Access. The terms bar users in the United States, the United Kingdom, the European Union, the Philippines and sanctioned territories. Availability is not a criterion.

Ostium vs dYdX and GMX

dYdX also scores 8.6 and GMX 8.4. dYdX beats Ostium on fees (9), funding and liquidation (9) and licence (10, for its AGPL-licensed chain), but its audit disclosure scores 7 against Ostium's 10. GMX also leads on fees and funding (9 each) and is one point behind on audits (9), but its licence scores 8 and its risk documentation 7. Ostium's place at the top comes from having no weak criterion: its lowest mark is 8, while every other venue in the category has at least one mark of 7 or below.

Who this rating suits

The score describes the most evenly documented venue in the category, with a current audit record and public contracts. It is most useful to traders who want leveraged exposure to traditional markets and want to read the code, the audits and the liquidation rule before trading. It suits less well anyone who wants a conventional funding rate or depends on recovering collateral after liquidation. The score assesses documentation and is not a recommendation to trade with leverage.