Positive Slippage Retention
The Formal Definition
An asymmetric dealing-desk execution practice where a broker passes negative market slippage straight through to the customer when the price moves against them, but quietly pockets the positive price improvement when the market moves favorably.
Retained Asymmetric Skim = max(0, Execution Price_{Favorable} - Limit Price_{Client})
Cole Barrett's Reality Check
The Unvarnished Bottom Line"Heads they win, tails you lose. If you place a limit order and the market moves against you by two cents, a shady dealing desk will fill you at the worse price and claim 'market volatility.' But if the market moves two cents in your favor, they fill you at your original price and pocket the extra two cents themselves. That's positive slippage retention, and it's pure theft."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: Executing 1,000 shares on a market order during a fast-moving, high-liquidity morning session
| Execution Metric | Symmetrical Price Improvement Broker | Asymmetric Dealing-Desk App |
|---|---|---|
| Fee / Rate | $0.005/share ($5.00 total) | $0 advertised commission |
| Spread / Buffer | Order routed to an exchange; price moved $0.03 in the trader's favor before execution | The same 3-cent favorable price move occurred on an internalized order book |
| Execution / Status | Broker filled the order at the improved price, passing the full 3-cent price improvement to the client | Dealing desk filled the customer at their original quoted price and kept the $0.03 price improvement internally |
| Total Cost / Result | Transparent, symmetrical best execution | Lost rightful market savings to asymmetric dealing desk rules |
How Brokers Weaponize This Term
Check your broker's Best Execution policy documents. If the text does not explicitly commit to 'Symmetrical Slippage' across both positive and negative market movements, they are legally reserving the right to pocket your positive price improvements.
Broker Evaluation Matrix
Cole Approves
Interactive Brokers: Audited quarterly for Best Execution compliance, passing through hundreds of millions in verified price improvements directly to clients annually.
Read Audit →Cole Flags / Avoids
Offshore CFD Dealing Desks: Uses software plugins to systematically capture positive price improvements while passing through all negative slippage to users.
View Trap Details →Frequently Asked Questions
Is positive slippage retention legal in regulated markets?
Under US SEC and UK FCA best-execution rules, retaining positive price improvement on equity orders is strictly prohibited. However, it still occurs in lightly regulated offshore forex and CFD brokers.
How can I verify if I am receiving price improvement?
Check your trade execution confirmations. Compliant brokers include a dedicated line item showing the exact dollar amount of price improvement relative to the prevailing NBBO.