What Are Interest Rate Swaps and How Do They Work?

January 2008

Interest-rate swaps have become an integral part of the fixed-income market. These derivative contracts, which typically exchange – or swap – fixed-rate interest payments for floating-rate interest payments, are an essential tool for investors who use them to hedge, speculate, and manage risk.

This article aims to explain why swaps have become so important to the bond market. It begins with a basic definition of interest-rate swaps, outlines their characteristics and compares them with more familiar instruments, such as loans. Later, we examine the swap curve, some of the uses of swaps, and the risks associated with them.

What is a Swap?

An interest rate swap is an agreement between two parties to exchange one stream of interest payments for another, over a set period of time. Swaps are derivative contracts and trade over-the-counter.

The most commonly traded and most liquid interest rate swaps are known as “vanilla” swaps, which exchange fixed-rate payments for floating-rate payments based on LIBOR, the interest rate high-credit quality banks (AA-rated or above) charge one another for short-term financing. LIBOR, “The London Inter-Bank Offered Rate,” is the benchmark for floating short-term interest rates and is set daily.) Although there are other types of interest rate swaps, such as those that trade one floating rate for another, plain vanilla swaps comprise the vast majority of the market.

By convention, each participant in a vanilla swap transaction is known by its relation to the fixed rate stream of payments. The party that elects to receive a fixed rate and pay floating is the “receiver,” and the party that receives floating in exchange for fixed is the “payer.” Both the receiver and the payer are known as “counterparties” in the swap transaction.

Investment and commercial banks with strong credit ratings are swap market-makers, offering both fixed and floating-rate cash flows to their clients. The counterparties in a typical swap transaction are a corporation, a bank or an investor on one side (the bank client) and an investment or commercial bank on the other side. After a bank executes a swap, it usually offsets the swap through an interdealer broker and retains a fee for setting up the original swap. If a swap transaction is large, the interdealer broker may arrange to sell it to a number of counterparties, and the risk of the swap becomes more widely dispersed. This is how banks that provide swaps routinely shed the risk, or interest-rate exposure, associated with them.

Initially, interest rate swaps helped corporations manage their floating-rate debt liabilities by allowing them to pay fixed rates, and receive floating-rate payments. In this way, corporations could lock into paying the prevailing fixed rate and receive payments that matched their floating-rate debt. (Some corporations did the opposite – paid floating and received fixed – to match their assets or liabilities.) However, because swaps reflect the market’s expectations for interest rates in the future, swaps also became an attractive tool for other fixed-income market participants, including speculators, investors and banks.

As a result, the swap market has grown immensely in the past 20 years or so; the notional dollar value of outstanding interest rate swaps globally was $230 trillion at the end of 2006, according to the Bank for International Settlements. Swap volume is termed “notional” because principal amounts, although included in total swap volume, are never actually exchanged. Only interest payments change hands in a swap, as described below.

Characteristics of Interest Rate Swaps

The “swap rate” is the fixed interest rate that the receiver demands in exchange for the uncertainty of having to pay the short-term LIBOR (floating) rate over time. At any given time, the market’s forecast of what LIBOR will be in the future is reflected in the forward LIBOR curve.

At the time of the swap agreement, the total value of the swap’s fixed rate flows will be equal to the value of expected floating rate payments implied by the forward LIBOR curve. As forward expectations for LIBOR change, so will the fixed rate that investors demand to enter into new swaps. Swaps are typically quoted in this fixed rate, or alternatively in the “swap spread,” which is the difference between the swap rate and the U.S. Treasury bond yield (or equivalent local government bond yield for non-U.S. swaps) for the same maturity. Swap spreads are discussed in more detail in the next section.

In many ways, interest rate swaps resemble other familiar forms of financial transactions, and it is helpful to think of swaps in these terms:

Exchanging Loans. Early interest rate swaps were literally an exchange of loans, and this model still provides an intuitive way to think about swaps. Consider two parties that have taken out loans of equal value, but one has borrowed at the prevailing fixed rate and the other at a floating rate tied to LIBOR. The two agree to exchange their loans, or swap interest rates. Since the principal is the same, there is no need to exchange it, leaving only the quarterly cash flows to be exchanged. The party that switches to paying a floating rate might demand a premium or cede a discount on the original fixed borrower’s rate, depending on how interest rate expectations have changed since the original loans were taken out. The original fixed rate, plus the premium or minus the discount, would be the equivalent of a swap rate.

The Financed Treasury Note. Receiving fixed rate payments in a swap is similar to borrowing cash at LIBOR and using the proceeds to buy a U.S. Treasury note. The buyer of the Treasury will receive fixed payments, or the “coupon” on the note, and be liable for floating LIBOR payments on the loan. The concept of a “financed Treasury” illustrates an important characteristic that swaps share with Treasuries: both have a discrete duration, or interest rate sensitivity, that depends on the maturity of the bond or contract.

The Swap Curve

The plot of swap rates across all available maturities is known as the swap curve, as shown in the chart below. Because swap rates incorporate a snapshot of the forward expectations for LIBOR and also reflect the market’s perception of credit quality of these AA-rated banks, the swap curve is an extremely important interest rate benchmark.

Because the swap curve reflects both LIBOR expectations and bank credit, then, it is a powerful indicator of conditions in the fixed income markets. In certain cases, the swap curve has supplanted the Treasury curve as the primary benchmark for pricing and trading corporate bonds, loans and mortgages.

Uses for Swaps