Swaps Are Not Just a Cost
Everyone hates swap. Most people don't understand what it actually is. Some people make money from it.
What swap actually represents
Swap is not a broker fee. It's not a penalty for holding overnight. It's the interest rate differential between the two currencies in your pair. Every currency is controlled by a central bank that sets an interest rate. When you hold a forex position, you're long one currency and short another. You earn interest on the one you're long, and you pay interest on the one you're short.
The swap is the net result of those two rates. That's it. The broker just passes it through.
Example: USD/JPY
The US Federal Reserve sets a positive interest rate. The Bank of Japan has historically maintained near-zero or negative rates. When you go long USD/JPY, you're earning US interest and paying Japanese interest. The net result is positive: you get paid for holding the position.
Go short USD/JPY and the maths reverses. You pay US rates and earn Japanese rates. Net result: negative swap, you pay. Same instrument, same broker, different direction, completely different swap outcome.
The reason most traders think swap is always a cost is because they mostly trade major pairs in directions where the differential works against them, or because rates have been close to zero across the board for years. But that's a specific market environment, not a law of nature.
When swap becomes the strategy
In 2017 I ran an active strategy trading EUR/NOK and USD/SEK in opposite directions. The gross P&L was deep in the red for months. On paper it looked like a disaster. But the net P&L? Thousands of dollars in profit.
The interest rate differentials on those pairs were so large that the daily swap payments more than covered the unrealised position loss over time. The positions were losing money on price movement but making more money on swap than they were losing on the trade. All I had to do was wait for the prices to converge, offset the position loss, and exit with the accumulated swap profit on top.
This is not some exotic edge case. It's a well-known approach called carry trading. Institutional desks have run carry strategies for decades. The principle is simple: find pairs with large interest rate differentials, position in the direction that pays you swap, and let time do the work. The trade doesn't need to move in your favour. It just needs to not move too far against you.
Not every market environment supports carry trades. When rates converge globally, the differentials shrink and the strategy stops working. But when central banks diverge on policy, the opportunities are real and they pay daily.
"Swap Free" accounts
There is no such thing as free.
Brokers offer "Islamic accounts" or "swap-free accounts" to accommodate traders whose faith prohibits receiving or paying interest. The swap line on your statement shows zero. Problem solved, right?
No. The broker still pays the interest on their side. That cost doesn't disappear because your account label changed. It gets redistributed into your other fees. Wider spreads, higher commissions, "administration fees," or some other creative line item that covers the same cost without calling it interest.
The broker is not absorbing the interest cost out of charity. They're using the additional margin they make on your inflated spreads and commissions to pay the interest for you, behind the scenes, so the word "interest" never appears on your statement. The economics are identical. The accounting label is different.
If your broker offers a swap-free account with the exact same spreads and commissions as a standard account, one of two things is happening: they're eating the cost (unlikely, brokers are not charities) or they're hedging your positions differently in a way that doesn't involve overnight financing (possible on some instruments, not all). Either way, somebody is paying. If you can't see who, it's probably you.
For the mechanics of when and how swap is applied, see Rollover & Swap.