Swap Definition: A swap is a derivative contract in which two parties agree to exchange streams of cash flows on set dates for a fixed period, such as fixed interest payments for floating ones or payments in one currency for another. The payments are calculated on a reference amount called the notional, which usually never changes hands. A swap starts with a value close to zero, and each side gains or loses as rates or prices move away from the levels fixed at the start.
What Is a Swap?
Picture two borrowers who each have the loan the other one wants. One pays a rate that rises and falls with the market, and would prefer certainty. The other pays a fixed rate and expects rates to fall. Instead of refinancing, they can sign a swap: each agrees to cover the other’s payments, and only the difference moves between them.
That is the whole idea. A swap is a type of derivative, meaning its value comes from something else, whether an interest rate, an exchange rate, a stock index or a commodity price. Nobody buys the underlying asset. The two sides simply agree on a formula for who pays whom, how much and when.
Swaps went mainstream in August 1981, when the World Bank and IBM signed a currency swap arranged by Salomon Brothers. The World Bank wanted Swiss francs and Deutsche marks but faced limits on borrowing in those markets, while IBM had debt in both currencies and wanted dollars. The World Bank raised dollars and swapped the payments with IBM, and both ended up with cheaper funding in the currency they needed.
How Does a Swap Work?
Every swap has four building blocks. The notional amount sets the size of the payments. The legs are the two payment streams, one for each party. The payment dates and the maturity set how often money moves and when the contract ends.
Most swaps are agreed over the counter, directly between two parties or through a dealer bank, under a standard legal contract called the ISDA Master Agreement. When both legs are in the same currency, the parties net the payments, so only the difference is paid. Cross-currency swaps are the exception, because two different currencies cannot be netted.
Take a five-year cross-currency swap between a US company that needs €100 million for a German factory and a European company that needs dollars. At the start, with EUR/USD at 1.10, the US firm pays $110 million and receives €100 million. Each year it pays 3% interest in euros (€3 million) and receives 5% in dollars ($5.5 million), which matches the interest it owes on its own dollar debt.
After five years, they swap the principal back at the same 1.10 rate, whatever the market rate is by then. Suppose the euro has fallen to 0.95 dollars. Without the swap, the US firm’s euro assets would be worth $15 million less in dollar terms. With it, the exchange rate for the principal was locked on day one, and the European company carries the other side of that move.
Types of Swaps
Interest rate swaps exchange fixed interest for floating interest in one currency. They are the largest part of the swap market by notional value, and banks, companies and pension funds use them to reshape their exposure to rate changes.
Currency swaps exchange principal and interest in two currencies, as in the example above. Central banks also run currency swap lines with each other to supply dollars to foreign banks during funding stress.
Credit default swaps pay out if a borrower defaults, in exchange for a regular premium. They work like insurance on a bond, but the buyer does not need to own the bond.
Total return swaps pass the full return of an asset, price change plus income, from one party to another in exchange for a financing rate. Commodity swaps fix the price of oil, gas or metals, so an airline can pay a set price for jet fuel while it buys fuel at the market price.
Swap vs. Futures Contract
Both instruments lock in a price or rate for the future, but they are built differently.
| Swap | Futures Contract | |
|---|---|---|
| Where it trades | Mostly over the counter, some on regulated platforms | On an exchange |
| Terms | Custom notional, dates and maturity | Standard size and expiry dates |
| Payments | Series of payments over months or years | Daily margin settlement until expiry |
| Typical maturity | One to 30 years | Weeks to a few years |
| Counterparty | The other party or a clearing house | Always the exchange clearing house |
In practice, a long-dated swap works like a strip of futures contracts joined into one agreement. Traders often use futures for short-term views and swaps for exposure that must match a specific loan or bond.
Why Are Swaps Important for Traders?
Swap rates carry information. The fixed rate on a two-year or ten-year interest rate swap shows where large banks and funds expect short-term rates to average over that period, so swap markets move within seconds of a central bank decision or an inflation surprise. Currency traders watch swap spreads between two economies for the same reason they watch bond yield spreads.
The main risk is counterparty risk: a swap is only as good as the party on the other side. In September 2008, AIG faced collateral calls on credit default swaps it could not meet, and the US government stepped in with an $85 billion credit line. After that, the G20 agreed in 2009 that standard swaps should be cleared through central clearing houses, which collect margin from both sides every day.
Leverage inside the formula is a second danger. In April 1994, Procter & Gamble took a pretax charge of $102 million on two swaps sold by Bankers Trust whose payments were tied to a multiple of rate moves. When the Fed began raising rates that year, a small rise in rates produced a much larger rise in what P&G owed. A swap with a simple fixed-for-floating formula carries none of that multiplier.
Key Takeaways
- A swap is a contract to exchange two streams of cash flows over time, calculated on a notional amount that usually never changes hands.
- Swaps let borrowers and investors change the kind of exposure they hold, fixed to floating or one currency to another, without selling assets or refinancing debt.
- The main families are interest rate swaps, currency swaps, credit default swaps, total return swaps and commodity swaps.
- A swap starts near zero value, and every move in the underlying rate or price becomes a gain for one side and an equal loss for the other.
- Counterparty risk and leveraged payment formulas are the two classic sources of swap losses, which is why standard swaps now go through central clearing.
Do you have to own the underlying asset to enter a swap?
No. A swap is a contract on cash flows, so neither side needs to own the bond, loan or asset the payments are based on. That is why swaps are used both to hedge existing exposure and to take new positions.
What does notional amount mean in a swap?
The notional is the reference amount used to calculate the payments, not money that changes hands. In a $100 million interest rate swap, the parties exchange only the interest calculated on $100 million, which is often a small fraction of it.
Are swaps traded on exchanges?
Most swaps are still agreed over the counter between two parties, but since the post-2008 reforms many standard interest rate and credit swaps must be executed on regulated platforms and cleared through a central clearing house. Custom swaps remain bilateral.
Is a forex swap the same as a currency swap?
Not quite. A forex swap is a short-term deal that buys a currency now and sells it back at a set date, while a cross-currency swap runs for years and includes regular interest payments in both currencies.
