Commission currency conversion and the cost that drifts

[Amanhasnoname]

Commissions are often quoted in dollars, but charged in the account currency. For accounts in other currencies, the conversion rate used by the broker may differ from the market rate, and the amount charged each trade fluctuates.

On a euro account paying seven dollars per lot, the euro cost changes as EUR/USD moves. Over the year, the drift can be several percent, small but real for a high-volume scalper.

Some brokers add a conversion spread on top of the commission. Others convert at an internal rate that updates only daily, which can create small gains or losses depending on direction.

The cleanest way to find out is comparing the actual charged commission in the statement with the quoted dollar value and the market rate at that time. Differences point to the broker's method.

A related cost applies to profits and losses on pairs not involving the account currency. Each close converts the result at the current rate, and the conversion pair's spread applies.

How does the commission charged compare to the advertised figure after conversion?