Futures 101: Contracts, Margin & Leverage

A futures contract is a standardized agreement to buy or sell a fixed quantity of something — an equity index, a barrel of oil, an ounce of gold — at a set price, on a set future date, on a regulated exchange. You are not buying the index or the oil today. You are agreeing on a price now and settling the difference later. That single idea is what makes futures both powerful and dangerous for a retail trader, and it is why they need to be understood before they are traded.

Contracts are standardized — and bigger than they look

The exchange defines everything about the contract so that buyers and sellers never have to negotiate terms — only price. Take the two contracts most retail traders meet first:

• ES — the E-mini S&P 500 future. One contract represents 50 times the index level. If the S&P trades near 5,000, one ES contract controls roughly 250,000 USD of exposure. That is a large position for most retail accounts.
• MES — the Micro E-mini S&P 500, one tenth the size of ES, so about 25,000 USD of exposure near the same level. The "micro" contracts (MES, MNQ, MGC, MCL) exist precisely so smaller accounts can size sensibly.

The key word is notional — the full economic value the contract controls. You do not put up the notional. You put up a deposit called margin, and that gap between your deposit and the notional is leverage.

Margin in futures is not margin in stocks

This trips up traders coming from equities, so it is worth being precise. In the stock world, "margin" means a loan: Regulation T has required 50% initial margin since 1974, and brokers charge interest on the borrowed half. Futures margin is a different animal — it is a good-faith performance bond, not a loan, and no interest is charged.

• Initial margin — what you must have in the account to open one contract. It is set by the clearinghouse using a scenario-based risk model (CME's system is called SPAN, now moving to a value-at-risk successor) that asks "how much could this position lose in one rough day?" and requires roughly that much.
• Maintenance margin — a slightly lower level you must stay above to keep the position open. Drop below it and you get a margin call: deposit more or the position is liquidated.

Because the margin can be a small fraction of the notional, the leverage is high. If one contract controls 250,000 USD of exposure on a 12,000 USD initial margin, you are levered about 20 to 1. Some retail brokers advertise far lower "day-trade margins" intraday, pushing leverage even higher.

Leverage is symmetric. A move that doubles your margin in a morning is the same size move, in the other direction, that wipes it out. The contract does not know which way you are rooting.

Why the leverage risk is real

This is the part that costs beginners money, so it gets its own section rather than a footnote. With 20-to-1 leverage, a 5% move in the underlying is a 100% move in your margin. Markets routinely move 1–2% in a session; an unexpected headline can move them more. A position that felt comfortable at the open can issue a margin call by lunch.

Two structural features make it sharper than equities:

• Mark-to-market every day. Futures gains and losses are swept in and out of your account daily. You cannot quietly hold a losing position and hope; the loss is debited and your margin must hold.
• Forced liquidation. Drop below maintenance and the broker can close you out at the market, at whatever price exists right then. You do not choose the exit.

None of this means avoid futures. It means size for the notional and the stop, never for the margin. The margin tells you what you are allowed to open; it tells you nothing about what you should risk. The right anchor is the same as in any market: decide the money you are willing to lose on the trade, measure the distance to your stop, and let those two numbers set the number of contracts.

Use a fixed fraction of your account (commonly 1%) as the risk per trade, then size from your stop distance — the leverage takes care of itself when the position is sized off risk rather than off how many contracts the margin "lets" you buy:

In FSP, the daily-loss-limit indicator is your circuit breaker against exactly the leverage spiral this lesson warns about — a string of fast, levered losses. Set it in units you respect and stop when it trips.

Put it to work in FSP: log each futures trade with its entry, stop, and contract count so the journal can hold you to a fixed risk per trade, and watch the daily-loss-limit indicator rather than your margin balance to decide when the session is over.