Margin call
A warning from the broker when account equity falls below a certain percentage of the required margin; positions can then be forcibly closed (stop-out).
The margin call level varies from broker to broker (common: 100% warning, 50% stop-out). At stop-out the broker closes positions starting with the biggest loser.
A trader who uses proper position sizing doesn't see margin calls; they almost always come from excessive leverage and trading without stops.
Related terms
Where it appears in the guides
Guides whose text uses this term; most frequent first.