Updated 2026-07-25
Maintenance margin is the minimum equity a leveraged position must maintain to stay open. It is normally expressed as a percentage of position notional, and it is the threshold that defines the liquidation price. Initial margin is what you must post to open the trade; maintenance margin is the smaller amount you must keep to stay in it.
The important wrinkle on perpetual venues is tiering. Maintenance-margin rates step up with position size, so a larger position faces a stricter requirement and, all else equal, a closer liquidation price than a small one at the same nominal leverage. Exchanges publish these tiers in a risk-limit table. When a position grows across a tier boundary, the requirement changes underneath it, which is why traders who size up sometimes find their liquidation level closer than they expected.