The Weekly Cost of Overtrading in Plain Numbers

[Fairman]

The Weekly Cost of Overtrading in Plain Numbers

Scenario: two traders have the same strategy and the same account of 10,000 dollars. Trader A takes 5 trades a week. Trader B takes 20, adding marginal setups. Each trade risks 100 dollars, with a stop of 25 pips on EUR/USD at 0.40 lots, and the spread costs 1.2 pips per trade.

Work it out. Spread cost per trade: 1.2 pips at 0.40 lots is 4 dollars per pip times 1.2, which is 4.80 dollars. Trader A pays 24 dollars a week. Trader B pays 96 dollars.

Now the edge. Suppose the original 5 setups have an expectancy of plus 0.25R, or 25 dollars per trade before costs. A earns 125 dollars before costs, 101 after. Suppose the extra 15 marginal trades have an expectancy of minus 0.1R, or minus 10 dollars per trade before costs. They contribute minus 150 dollars before costs, and minus 222 after costs of 72.

Trader B's week: 125 minus 150, which is minus 25 before costs, and minus 121 after costs of 96.

The same strategy, the same account, and the difference is 222 dollars a week, simply from adding trades with no edge.

Over a year, that is more than 11,000 dollars, more than the whole account.

Takeaway: every marginal trade must clear its costs and add edge. If it does not, skipping it is the profitable decision.

Practical step: separate your A-setups from your marginal trades in the journal, and compare their expectancy.

[FXS Prop Desk]

Each trade risks 100 dollars, with a stop of 25 pips on EUR/USD at 0.40 lots, and the spread costs 1.2 pips per trade.

The useful lesson here is that B's extra 15 trades are not free even if they break even before costs. At 1.2 pips per trade and 0.40 lots, each one costs about 4.80 dollars in spread, so roughly 72 dollars a week just to take marginal setups. Over a year that is a meaningful drawdown created entirely by activity.

[Fairman]

B's extra 15 trades are not free even if they break even before costs.

Exactly, and on a prop account that cost bites harder than people expect. 72 dollars a week is about 3,700 a year, which on a 10,000 account is 37 percent gone to the spread on trades with no edge at all. If the firm has a 10 percent max loss, breakeven overtrading alone would use that up in under 14 weeks, before a single real losing streak.

Commission makes it worse. Add a typical 7 dollars per round lot and each 0.40 lot trade carries another 2.80, so the true cost of a marginal setup is about 7.60, or 114 dollars a week for those 15 trades.

The filter I use is simple: if I can't name the setup from my playbook in one word before clicking, the trade doesn't happen. That cut my weekly count from around 25 to 9, and net profit went up even though gross pips went down.