Daniel ran a $50,000 CFD account and averaged 58 winning trades a month. His win rate sat at 61%. By every technical measure, he was a competent trader. Yet month after month his P&L finished negative. The culprit was not his entries or exits — it was the silent $1,340 in overnight swap charges bleeding out while he slept.

Overnight interest, called a swap rate or rollover cost, is charged when a leveraged position is held past the daily cut-off — typically 5pm New York time. Brokers apply a formula derived from the interest rate differential between the two currencies or instruments involved. On a 20-lot AUD/USD long held for 15 nights, that is not a rounding error. It is a structural cost that must be factored into every position sizing decision before the trade is placed.

CONCEPTSwap costs are a fixed drag on leveraged positions — model them before entry, not after the loss.
WARNINGHolding 10+ positions overnight at high leverage can generate swap charges that exceed a week of trading gains.
KEY IDEABreak-even pip calculations are incomplete without overnight cost — recalculate every position target to include it.

The maths are straightforward. If a broker charges a swap rate of 0.0045% per night on a $10,000 notional position, that is $0.45 per night. Across 20 positions averaging $8,000 notional each, the nightly cost is $72. Over 22 trading nights in a month, total swap charges reach $1,584. Against a $50,000 account, that is 3.17% of capital consumed before a single losing trade is counted.

Swap Drag vs Gross P&L — $50,000 Account$6k$4k$2k$0-$2kGross P&LSwap DragJanMarMayJulSepNovMonthly compounding swap cost erodes otherwise positive returns

The fix is to build swap into position sizing using a cost-adjusted fixed fractional model. Risk no more than 1% of account per trade — on a $50,000 account that is $500 — then subtract the projected swap cost from that risk budget before calculating lot size. If a three-night hold will cost $18 in swap, the trade's maximum acceptable pip loss must shrink accordingly. This keeps total risk, including carry costs, within the original 1% envelope. Traders researching this further can reference the mechanics of swap rate calculations on Investopedia, the broader concept of carry cost in leveraged investing on Wikipedia, and position sizing frameworks explained through the fixed fraction method on Investopedia.

Daniel's account did not fail because his analysis was wrong. It failed because he never modelled the cost of time. Every night a position stays open, the market charges rent — and disciplined traders pay that rent before it pays itself.

This content is for educational purposes only and does not constitute financial product advice. Past performance is not indicative of future results. Profit Logic Ltd (ACN 688 669 936) accepts no responsibility for errors or omissions in this content or anywhere on this website. Always seek advice from a licensed financial adviser before making investment decisions.