Fill Rate
Fill rate is the percentage of a trader's orders that are executed at the requested price and volume, without partial fills, rejections, or significant slippage.
Quick Definition Box
Fill rate measures execution quality: how many of your orders get filled exactly as you sent them, and how much of the requested volume actually gets traded. A high fill rate means your broker's liquidity providers can absorb your order size at the quoted price; a low fill rate signals thin liquidity, requotes, or partial fills.
Detailed Explanation
Fill rate is a core execution metric in forex and CFD trading. It answers a simple question: when you click "buy" or "sell," does the broker actually get your order filled at the price you saw, for the full size you requested? In practice, fill rate is expressed as a percentage—for example, 97% means that out of 100 orders, 97 were filled at the requested price and volume, while 3 experienced slippage, partial fills, or rejection.
The fill rate you experience depends heavily on the broker's execution model. Under a market-maker model, the broker is your counterparty. They can always fill your order because they take the opposite side—but they may quote a wider spread or requote you if the market moves against them. Under an ECN (Electronic Communication Network) or STP (Straight Through Processing) model, your order is routed to external liquidity providers. Here, fill rate depends on the depth of the aggregated order book. If your order size exceeds the available liquidity at the best price, you get a partial fill, and the remainder is filled at the next available price (slippage).
A common misconception is that fill rate is solely about speed. Speed matters, but fill rate is about completeness and price fidelity. A fast execution that fills only 50% of your order at the requested price is a poor fill rate. Similarly, an order that fills instantly but at a price 2 pips worse than quoted has a lower fill rate in quality terms, even if the time-to-fill was milliseconds.
Another factor is the type of order. Market orders are almost always filled, but the fill price may slip. Limit orders are only filled if the market reaches your price—so a limit order that never triggers isn't a "failed fill" but a sign that your price was never available. Fill rate statistics typically exclude limit orders that simply expire unfilled, focusing instead on market orders and stop orders where execution is expected.
Finally, fill rate is not a static number. It varies with market volatility, news events, and trading hours. During major economic releases, liquidity thins and spreads widen, causing fill rates to drop even at top-tier brokers. A broker that advertises a 99% fill rate during normal trading may see that fall to 85% during a Non-Farm Payrolls spike.
Real-World Example
Imagine you trade EUR/USD with a 0.10 lot (10,000 units) order. Your broker quotes 1.1050/1.1052. You place a market buy order at 1.1052.
- Scenario A (High fill rate): Your order is filled instantly at 1.1052 for the full 10,000 units. Your fill rate for this trade is 100%.
- Scenario B (Partial fill): The broker fills 6,000 units at 1.1052, but the remaining 4,000 units are filled at 1.1054 because the liquidity at 1.1052 was exhausted. Your fill rate is 60% at the requested price, and you experienced 2 pips of slippage on the remainder.
- Scenario C (Rejection): The broker's system rejects your order entirely due to a "price not available" message, and you must re-enter at 1.1056. Your fill rate is 0% for that attempt.
Over a month, if you place 200 market orders and 190 are filled at the exact quoted price with full volume, your fill rate is 95%. The other 10 orders had slippage or partial fills.
Why It Matters for Traders
Fill rate directly impacts your profitability. Slippage and partial fills add hidden costs. For a scalper who trades 50 times a day, even 1 pip of average slippage per trade can erase a significant portion of their edge. For a swing trader using larger position sizes, a partial fill can leave you with an unintended smaller position, altering your risk-reward ratio.
Fill rate also affects your strategy's reliability. If you rely on precise entry and exit prices—for example, a breakout strategy that buys at a specific level—a low fill rate means your orders often execute at worse prices, turning a profitable system into a losing one. Conversely, a high fill rate gives you confidence that the prices you see are the prices you get, allowing you to backtest and forward-test with greater accuracy.
Moreover, fill rate is a key indicator of broker integrity. A broker that consistently shows high fill rates is likely routing orders to deep liquidity pools or managing risk well. A broker with low fill rates may be operating with thin liquidity, or worse, using requotes to avoid unfavorable trades. Monitoring your own fill rate over time can help you detect execution problems early.
Common Misconceptions
Misconception 1: "A 100% fill rate means no slippage ever."
False. A 100% fill rate can still include slippage if the broker defines "filled" as "executed at any price." Always ask how the broker calculates fill rate—at the requested price, or merely executed at all.
Misconception 2: "Market makers always have worse fill rates than ECN/STP brokers."
Not necessarily. A market-maker can guarantee a fill because they take the opposite side, but they may widen spreads to compensate. An ECN broker may have excellent fill rates during liquid hours but poor ones during thin markets. The model matters less than the broker's liquidity providers and technology.
Misconception 3: "Fill rate is the same as execution speed."
No. Speed is how fast your order is processed; fill rate is how completely and accurately it is filled. A fast fill at a bad price is a low-quality fill. A slow fill at the exact price is a high-quality fill. Both metrics matter, but they measure different things.
Related Terms
How XM Compares
XM operates under both STP and market-maker execution models depending on account type, and they publish execution statistics on their website, including average slippage and fill rates. XM's No Dealing Desk (NDD) accounts route orders directly to liquidity providers, which typically yields high fill rates during normal market conditions. However, like all brokers, XM's fill rates can degrade during high-impact news events or when trading exotic pairs with thin liquidity. Traders should review XM's official execution statistics and account specifications on their website to understand current performance, as these figures are updated periodically and vary by account type and instrument.
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⚠️ This glossary entry is educational. Forex/CFD trading carries high risk. This is not investment advice.
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