Definition
Margin
The collateral reserved to hold a position, set by leverage and size.
Margin usage caps concurrent exposure: hit 100% usage and new orders reject; deep floating losses can trigger margin calls or auto-liquidation before a rule breach even lands.
Weekend/crypto sessions sometimes apply raised margin requirements — another reason weekend rules exist.
Related terms
General industry definitions — individual firms define terms differently in their own ToS; the decoded rulebook for each firm is the source of truth. Educational, not financial advice.