Currency Conversion Fee (FX Markup)
The Formal Definition
The markup percentage added by a broker above the interbank foreign exchange rate when buying or selling assets denominated in a foreign currency.
FX Cost = Converted Capital ($) × FX Markup (%)
Cole Barrett's Reality Check
The Unvarnished Bottom Line"FX markup is how European and UK brokers quietly rob you on US stocks. They scream '0% commission' on Tesla and Apple, but charge a 0.50% to 1.50% currency conversion fee on every buy AND every sell. That's a 1.0% to 3.0% roundtrip toll on your principal."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: £10,000 converted to USD to buy US tech stocks and sold 1 year later
| Execution Metric | Interactive Brokers (0.002% Spot FX) | Legacy UK Broker (1.00% FX Markup) |
|---|---|---|
| Fee / Rate | $2.00 flat spot trade | $0 commission |
| Spread / Buffer | Roundtrip FX: $4.00 | Roundtrip FX: £200.00 |
| Execution / Status | Net FX Drag: 0.004% | Net FX Drag: 2.00% |
| Total Cost / Result | Institutional spot rate | Lost £200 directly to FX spread |
How Brokers Weaponize This Term
Retail brokers force auto-conversion on every trade without offering multi-currency cash sub-accounts, ensuring you pay FX conversion fees repeatedly on every transaction.
Broker Evaluation Matrix
Cole Approves
Interactive Brokers: Multi-currency holding accounts with interbank spot conversion.
Read Audit →Cole Flags / Avoids
High-Markup Retail Brokers: 0.5% to 1.5% auto-conversion on every single trade.
View Trap Details →Frequently Asked Questions
How can I avoid currency conversion fees?
Use brokers that support multi-currency accounts (e.g. IBKR), allowing you to convert currency once and hold USD for future trades.
What is a fair FX markup on retail trades?
Trading 212 charges 0.15%, XTB charges 0.50%, and Interactive Brokers charges interbank spot + $2 flat.