Definition
Initial margin is the minimum eligible collateral or account value required to open a leveraged position under applicable rules and platform controls.
In market context
It represents only a fraction of the position’s notional exposure and is not the maximum amount that can be lost. The requirement can vary by product, account, volatility, concentration, and regulation, while fees or internal buffers may increase the resources needed at entry. After opening, maintenance requirements and changing equity determine whether the position can remain open under current rules.
Risk context
Posting initial margin exposes the account to the full economic movement of the leveraged position, not merely the collateral amount.
Source
Use the primary source for fuller regulatory or market context.