What is cross margin?

A margin mode where the whole account balance backs all open positions, so profits on one cover losses on another.

With cross margin, free balance automatically supports every position. A losing position can draw on the whole account, which pushes its liquidation price further away.

The downside: a single bad position can drain the account and trigger liquidation of several positions at once. Hyperliquid uses cross margin by default; the alternative is isolated margin.

On HyperScan

That is why HyperScan calculates the effective leverage of the whole account, not only of a single position.