Margin & leverage

Perps are traded on margin: you post collateral and control a larger position with leverage. Two thresholds govern every position — initial margin (what you need to open or increase a position) and maintenance margin (the minimum you must keep to avoid liquidation).

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Collateral

Collateral is held as USDG, the protocol’s settlement stablecoin, in your Arcus account. Your account equity is your collateral balance plus the unrealized profit and loss of your open positions. See Onboarding & deposits for how funds arrive as USDG.

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Initial vs. maintenance margin

Each market sets its own initial and maintenance margin requirements based on its risk profile, expressed as a fraction of position notional.

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Cross and isolated margin

Arcus supports both cross margin (positions share the account’s collateral, so the whole balance backs every position) and isolated margin (collateral is allocated to a single position, capping its risk to that allocation). Every position is cross margin by default; isolated margin is live and can be enabled per market. See Cross & isolated margin for how each mode measures risk, how to switch modes, and how to move collateral onto and off an isolated position.

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Leverage

Leverage is the inverse of the initial margin requirement. Arcus supports up to 50x leverage; the maximum is set per market and published with each market’s parameters. Higher-volatility or less-liquid markets carry lower maximum leverage.

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Off-hours margin

For perps whose underlying has set trading hours (equities, commodity and index ETFs), Arcus raises the initial margin requirement while the underlying market is closed. This makes it more capital-intensive to open or grow positions during thin overnight and weekend liquidity, reducing the risk of disorderly moves and liquidation cascades. Maintenance margin is not raised off-hours — existing, adequately-margined positions are not pushed toward liquidation simply because the market closed. Crypto perps have no off-hours regime; their margin requirements are constant.

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Crossing the session boundary

The uplift is not a one-off charge applied at the close — it is a function of the market’s current session state, so it switches on at the RTH → off-hours boundary and switches back off when the session reopens: Nothing is snapshotted or carried over: the requirement reverts to exactly the in-session value at the reopen, and the effective maximum leverage recovers with it. Read the current state from GET /v1/markets — isOutsideRth tells you which of the two fractions is live, and regularTradingHours gives the session window (it is null for 24/7 crypto markets, which never transition). Across every RWA market today, offHoursInitialMarginFraction is 1.5× the in-session initialMarginFraction — a flat 50% increase in the initial-margin requirement while the underlying is closed. Effective maximum leverage drops in step: a market you can open at 10x in-session tops out near 6.7x off-hours, and a 5x market near 3.3x. This is the current configuration rather than a fixed protocol rule — the fractions are per-market, so read both fields from GET /v1/markets instead of hard-coding the ratio. Two consequences worth designing for:

• Your buying power changes without you trading. Because the requirement feeds the margin figures the API reports, freeCollateral falls at the RTH → off-hours boundary and recovers at the reopen, with no fill, transfer, or price move involved. Account equity itself is unaffected — only the collateral held against open positions changes. Don’t treat a drop across the boundary as an error or a missed fill.
• A position opened at max in-session leverage can sit below the off-hours initial-margin threshold. That is expected and is not a liquidation trigger: liquidation is governed by maintenance margin, which does not move. The position stays open and can still be reduced or closed; what you cannot do until the session reopens is open or increase while below the higher requirement.

A per-account leverage override does not opt out of the uplift. The override is floored at the market requirement, so off-hours it can only ever raise your requirement, never hold it at the in-session level. See Trading when the underlying is closed for the related funding and price-band behavior.