What happens if an MTF margin requirement is not maintained?

If the collateral value backing an MTF position falls below the required maintenance margin, typically because the stock price has dropped, you’ll receive a margin call from the broker, usually through an app notification, SMS, or email, asking you to add funds or additional collateral within a specified window, often the same day or very shortly after. If you don’t respond in time by topping up the margin, the broker has the right to square off (sell) enough of the position to bring the account back within required margin levels, and this forced sale happens at whatever price the market offers at that time, not necessarily a price you’d have chosen. This is one of the clearest risks of MTF: a margin shortfall doesn’t just sit there, it triggers action, sometimes on a compressed timeline that doesn’t give you much room to react if you’re not actively monitoring the position. You keep a buffer of available funds specifically for topping up MTF margin if needed, rather than running the position at the bare minimum required margin.