When the tighter-spread broker had worse stop fills

[FXS London Scalper]

A pattern traders sometimes report: they switch to a broker with tighter spreads, costs on entries drop, but stop losses fill worse. Net result: no saving, or even higher cost.

Why it can happen:
- Tighter spreads may come from a liquidity pool that thins out during fast moves.
- Different execution models: some brokers offer tight spreads but fill stops at the next available price after a gap, while others have more liquidity depth.
- The spread advertised is the average, but stop losses trigger during spread widening.

How to measure the real cost:
- Total cost per trade = spread + commission + entry slippage + exit slippage.
- Calculate this for both brokers over at least 100 trades each.
- Pay special attention to stop loss fills during volatile periods.

The broker with the lowest total cost is the cheapest, not the one with the lowest spread.

Have you seen this happen? A broker that looked cheaper but wasn't?