Futures Contracts Explained: Margin, Settlement & How They Work

A futures contract is one of the most widely traded instruments in global financial markets. From stock index futures used by portfolio managers to crude oil contracts used by energy companies, futures provide a standardized way to lock in prices and manage risk. While futures serve a similar economic purpose as forward contracts, their exchange-traded structure — with clearinghouse guarantees, margin requirements, and daily settlement — solves the counterparty risk and liquidity limitations of OTC forwards. This guide explains how futures contracts work, who uses them, and how they compare to forwards.

What Is a Futures Contract?

A futures contract is a standardized agreement, traded on a regulated exchange, to buy or sell a specific asset at a predetermined price on a specified future date. The exchange’s clearinghouse stands between every buyer and seller, substantially reducing the counterparty credit risk that exists in private OTC contracts.

Key terms to understand:

• Underlying asset — the commodity, stock index, currency, interest rate, or other asset being traded
• Contract size (multiplier) — the fixed quantity per contract (e.g., $50 per index point for E-mini S&P 500)
• Delivery month — the specified month in which the contract expires and settlement occurs
• Long position — the buyer, who profits when the futures price rises
• Short position — the seller, who profits when the futures price falls

Futures markets evolved in the 19th century at the Chicago Board of Trade (CBOT), where grain merchants needed a reliable way to lock in prices without the credit risk of bilateral agreements. The introduction of standardized contracts and a clearinghouse transformed forward-style trading from a risky private arrangement into the transparent, liquid marketplace that exists today.

Who Uses Futures Contracts?

Three main types of participants drive futures markets:

• Hedgers — use futures to reduce price risk. An airline might buy crude oil futures to lock in fuel costs, while a wheat farmer sells futures to guarantee a sale price before harvest.
• Speculators — take positions to profit from anticipated price movements. They provide liquidity to the market but accept significant risk in exchange for potential returns.
• Arbitrageurs — exploit price discrepancies between the futures market and the underlying asset (or between related contracts), keeping markets efficiently priced.

How Futures Markets Work

Three interconnected mechanisms make futures markets function: the clearinghouse, the margin system, and daily settlement. Together, they create a credit-safe environment that distinguishes futures from OTC derivatives.

The Clearinghouse

When a futures trade is executed, the exchange’s clearinghouse steps between the buyer and seller through a process called novation — it becomes the counterparty to both sides. The buyer’s contract is with the clearinghouse, not the original seller, and vice versa. This substantially reduces bilateral credit risk because each participant only needs to trust the clearinghouse, which is backed by member capital and guarantee funds.

The Margin System

Futures margin is a performance bond — a good-faith deposit ensuring each party can meet its obligations. It is not a down payment on the underlying asset.

• Initial margin — the deposit required to open a position (typically 3-12% of notional value)
• Maintenance margin — the minimum balance that must be maintained while the position is open (usually 70-80% of initial margin)
• Margin call — if the account balance falls below the maintenance margin due to adverse price moves, the trader must deposit additional funds to restore the account to the initial margin level
• Variation margin — the daily cash flow from marking to market (gains credited, losses debited)

Daily Settlement (Marking to Market)

At the end of each trading day, the exchange calculates a settlement price and adjusts every open position accordingly. Gains are credited and losses are debited from margin accounts in real time. This daily settlement process:

• Prevents large unrealized losses from accumulating (unlike forward contracts, which settle only at maturity)
• Greatly reduces credit exposure — under normal conditions, the maximum unsettled amount is limited to one day’s price movement (though overnight gaps or counterparty default at the clearing level remain residual risks)
• Creates real cash flows every day, even though the underlying asset hasn’t been delivered

As the contract approaches expiration, the futures price and the spot price converge — at expiry, they are effectively equal. This convergence is enforced by arbitrage: any gap between the two would create a riskless profit opportunity. For a deeper treatment of why futures prices differ from spot prices and how convergence works, see our guide on Futures Pricing & Valuation.

Futures Contract Specifications

Every futures contract has a set of fixed specifications defined by the exchange that never change during the contract’s life:

In addition to fixed contract specs, traders monitor market data to gauge liquidity and sentiment:

• Volume — the number of contracts traded in a given period. High volume means deep liquidity and tighter bid-ask spreads.
• Open interest — the total number of outstanding contracts that have not been closed or settled. Rising open interest alongside rising prices suggests strong bullish conviction; rising open interest with falling prices suggests strong bearish conviction.

Some contracts settle through physical delivery (e.g., crude oil, wheat — the actual commodity changes hands), while others use cash settlement (e.g., S&P 500 E-mini — the difference between the futures price and the final settlement price is paid in cash). The settlement method is fixed in the contract specifications and determined at the time the contract is listed.

Futures Contract Example

To calculate the daily profit or loss on a futures position, use the following formula:

Futures vs Forward Contracts

Futures and forwards serve the same fundamental purpose — locking in a price for future delivery — but differ significantly in how they manage credit risk, liquidity, and settlement.

In interest rate markets, OTC Forward Rate Agreements (FRAs) serve a similar hedging purpose to exchange-traded interest rate futures like SOFR and Treasury futures. The choice between OTC and exchange-traded instruments depends on the need for customization versus the benefits of standardization and central clearing.

How to Analyze Futures Contracts

When evaluating a futures contract for hedging or investment purposes, consider these key factors:

1. Contract specifications — understand the multiplier, tick size, delivery method, and expiration cycle. Misunderstanding these basics leads to position-sizing errors.
2. Liquidity (volume) — higher daily volume means tighter bid-ask spreads and lower execution costs. Front-month contracts are typically the most liquid.
3. Open interest — rising open interest indicates new money flowing into the contract, while declining open interest suggests positions are being unwound.
4. Margin requirements — determine the capital commitment and implied leverage. Higher-volatility underlyings require proportionally more margin.
5. Expiration and rollover — most hedgers and speculators close or roll their positions before expiration to avoid delivery. Rolling involves closing the expiring contract and opening the next delivery month, which may involve a cost (the roll yield).

Common Mistakes

Futures contracts are powerful instruments, but several common errors can lead to unexpected losses:

1. Underestimating leverage — A small margin deposit controls a large notional value. In our E-mini example, $12,650 controls $260,000 — roughly 20.6x leverage. A 5% adverse move in the S&P 500 would wipe out the entire margin deposit. Leverage amplifies losses just as much as gains.

2. Ignoring margin call risk — Daily settlement means adverse price moves trigger immediate cash demands. If you cannot meet a margin call, your broker will liquidate your position at the current market price — locking in losses regardless of your longer-term view.

3. Confusing futures price with spot price — During a contract’s life, the futures price typically differs from the spot price due to the cost of carry (financing costs minus any income from the underlying). The two converge only at expiration. See our Futures Pricing & Valuation guide for a detailed treatment of this relationship.

4. Holding contracts to expiry unintentionally — Physically delivered contracts (crude oil, wheat, gold) require the holder to take or make delivery of the actual commodity. Traders who forget to close or roll their positions before the delivery window can face unexpected logistical and financial obligations.

5. Ignoring basis risk when hedging — The futures contract and the asset being hedged may not move in perfect lockstep. This difference — basis risk — means the hedge may not fully offset price changes in the underlying exposure. Basis risk is especially relevant when the futures contract is on a different but related asset. For more on how basis and convergence affect hedging, see our guide on Futures Pricing & Valuation.

Limitations of Futures Contracts

1. Limited customization — Unlike forwards, futures cannot be tailored to specific quantities, dates, or delivery locations. A hedger needing 7,500 barrels of oil must choose between 7 or 8 contracts of 1,000 barrels each.

2. Margin ties up capital — While margin requirements are a fraction of notional value, they still represent capital that cannot be deployed elsewhere. For large institutional positions, the opportunity cost of tied-up margin can be meaningful.

3. Daily settlement creates cash flow volatility — Even when a hedge is ultimately effective, the daily mark-to-market process generates real cash inflows and outflows throughout the hedge period. This can create liquidity stress during periods of adverse price movement, even if the final hedging outcome is successful.

4. Rollover costs — Hedgers maintaining long-term positions must periodically “roll” from expiring contracts to the next delivery month. This rollover involves transaction costs and may involve paying a premium or receiving a discount depending on the term structure of futures prices (contango vs. backwardation).

5. Limited availability — Not every asset, commodity, or exposure has a liquid futures market. For niche or specialized hedging needs, OTC forwards or swaps may be the only viable option.