Many new traders focus on the spread and forget the other recurring cost, or sometimes credit: the swap, also called rollover or overnight financing. If you hold a position past the daily cutoff, usually 5 p.m. New York time, your account may be debited or credited. For short-term traders this may be small. For swing traders and carry strategies it can matter a lot.
Why swaps exist
Spot forex settles in two business days. To avoid delivering currency, brokers roll open positions forward each day. Rolling means effectively borrowing one currency to buy the other, and interest rates differ between currencies. The swap reflects that difference, adjusted by the broker's markup.
When you buy a pair, you are long the base currency and short the quote currency. You earn something like the interest rate of the currency you hold and pay the rate of the one you owe. If the long currency has the higher rate, the net can be positive. This is the logic behind the carry trade.
Why you may pay in both directions
Brokers take a margin on the rate differential. Even when the interbank differential favours your position, the credit you see can be smaller than theory suggests. Conversely, the debit on the opposite side can be larger than the differential. In some instruments both long and short swaps are negative. Check the broker's published swap table for each symbol; it is generally listed in the contract specifications and changes over time.
How swap is quoted
Brokers quote swap in different ways: in points (pips or fractions), in account currency per lot, or as an annual percentage. Convert to a common basis before comparing. Here is an illustrative calculation:
| Item | Illustrative value |
|---|---|
| Position | 1 standard lot (100,000 units) |
| Quoted swap, long | -4.50 account currency per night |
| Nights held | 10 |
| Total financing | -45.00 |
The figures are invented. In real use, read your own broker's table and, if possible, confirm with one overnight on a small position.
Triple swap Wednesday
Because settlement is two business days forward, a position rolled on Wednesday settles after the weekend, so brokers usually charge or credit three days of swap that night. For most major pairs that is Wednesday; for a few instruments the day differs. If you hold across that night, the cost or credit is about three times the usual amount. It is a common surprise for new traders reviewing a statement.
When swap matters
- Day traders who close before the cutoff pay no swap at all.
- Swing traders holding for days or weeks should include financing in the trade's expected return. A negative swap drags on a small edge.
- Carry strategies depend on it, but the interest earned is usually small relative to the exchange-rate swings. A carry trader can earn swap daily and still lose heavily when the pair drops; see safe-haven currencies for why carry positions can unwind abruptly.
- Exotic pairs often have large rate gaps and wide swaps, in either direction.
Swaps and changing rates
Because swaps follow policy rates, they shift when central banks move. A hawkish decision can change the sign of a pair's financing within days. When you plan a long hold, check the central bank calendar and the rate path discussed in interest rate expectations and currencies.
Swap-free (Islamic) accounts
Some brokers offer swap-free accounts for clients whose beliefs prohibit interest. These typically replace swap with other fees, such as an administration charge after a set number of days. They are not necessarily cheaper; compare the all-in cost before choosing.
How to account for it
- Look it up before you trade. Find the long and short swap for the symbol, and the day of the triple charge.
- Include it in your plan. Estimate the holding period and add the expected financing to your cost per trade; see the true cost of trading.
- Record it in your journal. Swaps often appear as separate statement lines. Matching them to trades gives a truer picture of performance; see a journal that improves results.
- Think about taxes. Interest and swap amounts may be treated differently from price gains in some jurisdictions. For a general starting point in Canada, see tax basics for Canadian forex traders, then confirm with a qualified professional.
Don't ignore the margin side
Negative swap reduces account equity, and a long hold with a thin buffer can drift toward a margin call. The mechanics are covered in margin calls and stop-outs.
Takeaway
Swap is easy to ignore on a one-day trade and expensive to ignore on a month-long one. Know the number, know the Wednesday rule, and treat financing as part of the trade's cost or return rather than a surprise on your statement.
Educational content only, not trading advice. Leveraged trading carries risk of loss.