Typical “real world” derivatives contracts don’t just disappear when someone runs out of margin — typically they have a predefined expiry date or other specific underlying price-related clauses that allow early close-out. As a result, if your counterparty — whoever is on the other side of your trade — fails to keep their margin collateral balance positive, you face the risk of default. You might not get paid what you’re owed, as stipulated by the terms of the contract!