How exactly do futures margin calls work, and what happens if I can't meet one?

Great question — futures margin mechanics are fundamental to FRM Part I and show up frequently on the exam. Let me walk through the full cycle. **How Futures Margins Work** When you open a futures position, the clearinghouse requires you to post an **initial margin** — a deposit that acts as a performance bond. There's also a **maintenance margin**, which is a lower threshold (typically 70–80% of the initial margin). Each trading day, your position is **marked to market**. Gains are credited and losses are debited from your margin account in real time. **Margin Call Trigger** A margin call occurs when your margin account balance falls **below the maintenance margin level**. When triggered, you must restore your account to the **initial margin level** (not just the maintenance level) — this is a common exam trap. **Worked Example:** Suppose you go long 5 crude oil futures at $78.50/barrel. Each contract is 1,000 barrels. | Parameter | Amount | |---|---| | Initial margin per contract | $6,200 | | Maintenance margin per contract | $4,800 | | Total initial margin (5 contracts) | $31,000 | | Total maintenance margin | $24,000 | **Day 1:** Oil settles at $77.20. Loss = (78.50 − 77.20) × 1,000 × 5 = **$6,500**. Account balance: $31,000 − $6,500 = **$24,500**. Still above maintenance ($24,000) — no margin call. **Day 2:** Oil settles at $76.40. Loss = (77.20 − 76.40) × 1,000 × 5 = **$4,000**. Account balance: $24,500 − $4,000 = **$20,500**. Now below maintenance ($24,000) — **margin call triggered**. You must deposit $31,000 − $20,500 = **$10,500** to restore to the initial margin level. **If You Fail to Meet the Call** If you don't post the variation margin by the deadline (usually the next business morning), the broker will **liquidate some or all of your position** at market prices to bring the account back into compliance. You're still liable for any remaining deficit. **Key Exam Tips:** 1. The margin call restores to **initial**, not maintenance. 2. Excess margin above the initial level can usually be withdrawn. 3. For **short positions**, gains occur when prices fall — the logic is symmetric. Our FRM Part I course covers the full spectrum of futures mechanics, including basis risk, calendar spreads, and cross-hedging strategies. Check it out for structured exam prep.