Order Types, Spread, Slippage, and Commissions

The Hidden Costs That Decide If Your Edge Survives

A profitable-looking strategy on paper can lose money in live trading purely because of execution costs. Understanding order types and what they actually cost you in real market conditions is not optional background knowledge — it's part of the edge calculation itself.

The Core Order Types

• Market order: Execute immediately at the best available price. Guarantees you get filled; does not guarantee the price you get filled at. In fast-moving markets, the fill price can differ meaningfully from the price you saw when you clicked.
• Limit order: Execute only at a specified price or better. Guarantees the price (or better); does not guarantee you get filled at all — if the market never trades at your limit, you simply don't get in (or out).
• Stop order (stop-market): Becomes a market order once a specified trigger price is reached. Commonly used for stop-losses. Same fill-price risk as a market order once triggered — in a fast move, your actual exit can be worse than your stop price.
• Stop-limit order: Becomes a limit order once the trigger price is reached. Protects against a bad fill price but introduces the risk of no fill at all if price moves through your limit too quickly — a real danger for a stop-loss, since the whole point of a stop is to guarantee an exit.

For most new futures traders, stop-losses should be stop-market orders, not stop-limit — you're trading certainty of exit for a small amount of price precision, and that trade-off almost always favors certainty when you're trying to cap a loss.

Bid-Ask Spread

Every tradable moment has a bid (the highest price a buyer will currently pay) and an ask (the lowest price a seller will currently accept). The difference between them is the spread. On a highly liquid contract like ES during NY AM hours, the spread is typically a single tick (0.25 / $12.50). On a less liquid product, or during low-volume overnight hours, the spread can widen to multiple ticks — meaning you're effectively paying more just to enter and exit, before the market has moved at all.

Slippage

Slippage is the difference between the price you expected to get and the price you actually got filled at. It happens most often with market orders during fast moves or low-liquidity periods — you click to buy at what shows as 18,502.00, but by the time your order reaches the exchange, the best available price is 18,502.50. That half-point difference, multiplied across your position size, is a real cost that never shows up on a backtest unless you explicitly model it in.

Slippage tends to be worse:

• During news releases and other high-volatility spikes
• In thin, overnight sessions
• When trading larger size relative to the available liquidity at the current price

Commissions

Most futures brokers charge a per-contract, per-side commission — meaning you pay once to enter and once to exit, per contract traded. A round-trip cost of a few dollars per contract sounds trivial on a single trade. It is not trivial across a full trading career:

Worked example: Say your broker charges $2.50 per side, per contract (a representative figure — VERIFY BEFORE LAUNCH with your actual broker's schedule). If you trade 3 MNQ contracts, round trip, that's 3 contracts x $2.50 x 2 sides = $15.00 in commissions on that single trade. If you make that same trade twice a day, five days a week, that's $150/week — about $7,800/year — in commissions alone, before accounting for a single dollar of spread or slippage.

Why This Changes How You Should Think About "Edge"

A strategy that wins 55% of the time with a 1:1 risk-reward ratio might look profitable in a spreadsheet. Once you subtract realistic spread, slippage, and commission costs per trade, that same strategy can easily become a net loser — not because the market read was wrong, but because the edge was never large enough to survive its own transaction costs.

This is why every risk and strategy lesson later in this course asks you to think in terms of net edge after costs, not gross win rate. A setup needs to clear a real bar, not just be "more right than wrong."

A Practical Rule

Before trusting any strategy — yours or anyone else's — ask: does the edge per trade meaningfully exceed the round-trip cost of spread plus commission on the contract you're trading? If the answer is "barely" or "no," the strategy is not ready for live capital, regardless of how good its win rate looks in isolation.