Definition
Fill ratio (also called fill rate) measures the proportion of trading orders that are executed at the trader's requested price or better, without being rejected, requoted, or partially filled. In a genuine No Dealing Desk environment, orders are passed directly to liquidity providers, and the fill ratio reflects how effectively this routing process works.
A high fill ratio indicates that the broker's liquidity aggregation and order routing infrastructure is functioning efficiently. Conversely, a low fill ratio may suggest last-look practices, insufficient liquidity depth, or intentional intervention in the execution process.
Formula
Fill Ratio = (Filled Orders / Total Submitted Orders) x 100%Where 'Filled Orders' includes orders executed at the requested price or with positive slippage, and 'Total Submitted Orders' includes all market and limit orders submitted during the measurement period.
For statistically significant results, we recommend a minimum sample size of 500 orders collected over at least 2 weeks of continuous trading across major sessions (London, New York, and Asian overlap).
Why It Matters
Fill ratio is the single most important execution quality metric because it directly impacts trading profitability. Every rejected or requoted order represents a missed trading opportunity -- and in fast-moving markets, the replacement execution is almost always at a worse price.
For algorithmic traders and scalpers, even a 2-3% drop in fill ratio can eliminate edge entirely. For longer-term traders, persistent requotes during news events or session opens indicate that the broker may be intervening in order flow rather than providing genuine market access.
- Directly correlates with execution reliability
- Indicator of genuine vs. simulated NDD execution
- Impacts strategy viability, especially for high-frequency approaches
- Should be measured across different market conditions
Benchmark Ranges
Based on our testing across 20+ NDD/STP/ECN brokers, the following ranges represent industry benchmarks for fill ratio:
| Rating | Range | Assessment |
|---|---|---|
| 98-100% | 98% -- 100% | excellent |
| 95-97% | 95% -- 97.9% | good |
| 90-94% | 90% -- 94.9% | fair |
| Below 90% | < 90% | poor |
Note that fill ratios naturally decrease during high-impact news events and periods of extreme volatility. Our benchmarks are based on composite measurements that include all market conditions.
Visualization
Distribution of fill ratios across our tested broker sample during standard market conditions (London/NY overlap, major pairs):
Influencing Factors
Several factors affect the fill ratio a trader will experience:
Liquidity Depth
Deeper liquidity pools from multiple LPs result in higher fill rates, especially for larger order sizes.
Order Size
Larger orders (> 10 lots on majors) naturally experience lower fill ratios due to available liquidity at a single price level.
Market Volatility
During high-impact news events, prices move faster than routing latency, causing more requotes.
Execution Model
Genuine A-Book brokers route to LPs directly, while B-Book brokers may apply last-look, reducing fill rates.