Passive Order Fill Ratio (Hit Rate)
The Formal Definition
A core execution quality auditing metric that measures the percentage of an investor's passive limit orders that execute completely within a specified timeframe without requiring cancellation or aggressive price adjustments across different brokers and routing venues.
Passive Fill Ratio (%) = [ Total Executed Passive Limit Volume / Total Dispatched Passive Limit Volume ] × 100
Cole Barrett's Reality Check
The Unvarnished Bottom Line"Your broker advertises '$0 commissions,' but what is your passive fill ratio? If you submit twenty limit orders at the bid and only three of them ever fill, your broker's order router is garbage. They are likely routing your flow to internalizers who cherry-pick the easy fills and leave the rest of your orders to rot while the market moves away."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: An active swing trader submitting 50 passive limit orders across a month of active equity trading
| Execution Metric | Smart-Routed Direct DMA Client (IBKR) | PFOF-Routed Retail Client |
|---|---|---|
| Fee / Rate | $0.0035/share DMA rate | $0 advertised commission |
| Spread / Buffer | Smart Order Router directed limit orders to venues with high fill probability and active price-time matching | Broker routed all limit orders to a single wholesale internalizer under a payment for order flow arrangement |
| Execution / Status | 42 out of 50 limit orders executed cleanly without modification (84% Passive Fill Ratio) | Wholesaler only filled orders when the market reversed hard; only 16 out of 50 orders filled (32% Passive Fill Ratio) |
| Total Cost / Result | High execution efficiency via optimized smart limit routing | Suffered severe opportunity drag from low passive fill rates |
How Brokers Weaponize This Term
Track your personal 'Passive Fill Ratio' in your trading journal. If your limit order fill rate on liquid stocks is below 60%, your broker is routing your flow to internalizers who are cherry-picking executions, costing you more in missed moves than you save in commissions.
Broker Evaluation Matrix
Cole Approves
Interactive Brokers: Provides institutional SmartRouting algorithms designed to maximize passive limit order fill probabilities across lit exchanges and dark pools.
Read Audit →Cole Flags / Avoids
Zero-Commission PFOF Apps: Routes limit orders to wholesale internalizers that frequently leave passive retail limit orders unfilled during trending markets.
View Trap Details →Frequently Asked Questions
What is considered a healthy passive fill ratio for swing traders?
For orders placed inside or at the National Best Bid/Offer on liquid US equities, a healthy passive fill ratio should sit between 75% and 85%.
Why do wholesale internalizers cause lower passive fill rates?
Because internalizers have no obligation to fill limit orders that do not match incoming retail marketable orders, often holding flow while lit exchange prices move away.