The mid-market swap rate is the midpoint between the bid and ask quotes a dealer shows for the fixed leg of an interest rate swap. It represents the theoretical fair value for exchanging floating-rate interest payments for fixed-rate payments over a given term, stripped of the dealer’s profit margin. Banks, corporate treasurers, and auditors treat it as the unbiased benchmark for valuing swaps, pricing new corporate debt, and measuring interest rate exposure across the trillions of dollars in contracts outstanding.
What an Interest Rate Swap Is
An interest rate swap is an agreement in which two parties exchange streams of interest payments over a set period. One side pays a fixed rate. The other pays a floating rate that resets periodically against a short-term benchmark, which in the United States is now the Secured Overnight Financing Rate (SOFR), a measure of overnight borrowing costs backed by Treasury securities.1Federal Reserve Bank of New York. Secured Overnight Financing Rate Data
Payments are calculated on a notional principal, but that principal never changes hands. Only the net difference between the two payment streams moves between the counterparties on each payment date.
The fixed rate agreed at the start of the contract is the swap rate. It is calibrated so that the present value of the expected floating payments equals the present value of the fixed payments. Neither party has an advantage on day one, and the swap has zero market value at inception.
Standard quoted tenors run 1, 2, 3, 5, 7, 10, 15, 20, and 30 years, with the five- and ten-year points carrying the heaviest trading volume.2Commodity Futures Trading Commission. Appendix A to Tradition SEF Rulebook – USD Interest Rate Swap Specifications Overall, tenors can range anywhere from 30 days to 50 years.3Commodity Futures Trading Commission. Swap Specifications
Bid, Ask, and the Midpoint
Dealers quote two rates for every tenor. The bid is the fixed rate the dealer will pay while receiving floating. The ask is the fixed rate the dealer will charge while paying floating. The ask is always higher than the bid, and the gap between them is the bid-ask spread, which is how the dealer gets paid for making the market.
The mid-market swap rate splits that spread in half. If a dealer quotes a five-year swap at 3.45% bid and 3.49% ask, the mid-market rate is 3.47%. At that rate, neither side has a built-in edge.
This matters because the mid removes the dealer’s markup from the number. When a bank marks its swap portfolio to market at the close of business, it uses the mid. When a corporate treasurer compares hedging costs across competing dealers, the mid provides the apples-to-apples comparison. When an auditor values a derivative on the balance sheet, the mid is the starting point, and adjustments for credit risk and funding costs get layered on afterward.
How the Rate Is Constructed
A single mid-market rate at one tenor doesn’t exist in isolation. It sits on a yield curve that connects mid-market rates across all maturities, from overnight out to 30 years or beyond. Building that curve is the central technical exercise, and the standard method is bootstrapping.
Bootstrapping the Curve
Bootstrapping works outward from the shortest maturities. You cannot solve for the ten-year rate until every maturity below it is locked down. At the short end, overnight and money-market rates convert directly into discount factors, the multipliers that tell you what $1 received on a future date is worth today.
For longer maturities, you use quoted par swap rates. A par swap has a useful property: the present value of its fixed-rate coupons plus the return of notional at maturity must equal the notional itself. If you already know the discount factors for years one through four, you can plug them in and solve for the year-five discount factor using the five-year swap rate. Repeat at each successive quoted maturity, and you extract a full set of zero-coupon discount factors from observable market prices. Forward rates, the market’s implied expectations for future short-term rates, fall out of the same curve.
The market only quotes liquid rates at standard maturities. For a swap maturing in four years and seven months, dealers interpolate. Linear interpolation draws a straight line between adjacent known points. Cubic spline methods produce smoother curves. The choice affects pricing of non-standard tenors, which is why dealers invest heavily in curve-fitting methodology.
OIS Discounting
Before 2008, dealers typically discounted swap cash flows using the same LIBOR-based curve that projected the floating payments. The crisis exposed the flaw: LIBOR embedded substantial bank credit risk and was not a reliable risk-free rate.
The industry moved to the Overnight Indexed Swap (OIS) curve for discounting. OIS rates are anchored to near-risk-free overnight lending rates and are widely regarded as the closest available proxy for a true risk-free rate. The approach, sometimes called collateralized discounting, reflects the reality that most interdealer swaps are now centrally cleared and backed by collateral, which effectively removes counterparty credit risk from the discount rate.4Federal Reserve Bank of New York. Thoughts on the Methodologies in the ISDA Consultation
The SOFR Floating Leg
SOFR works differently from LIBOR. LIBOR was a forward-looking term rate, so you knew the floating payment at the start of each period. SOFR is a backward-looking overnight rate, published each business day by the Federal Reserve Bank of New York at approximately 8:00 a.m. ET, based on actual overnight repo transactions collateralized by Treasuries.1Federal Reserve Bank of New York. Secured Overnight Financing Rate Data
Because SOFR is an overnight rate, the floating payment for a full accrual period of three or six months is calculated by compounding daily SOFR readings across the period. The standard convention is compounding in arrears, so the exact floating payment is not known until the accrual period is nearly complete.5Federal Reserve Bank of New York. SOFR In Arrears Conventions for Use in Bilateral Business Loans This is an operational shift from the LIBOR era, when treasurers could pin down exact payment amounts weeks in advance.
The mid-market fixed rate is then the rate that sets the present value of the projected compounded SOFR payments equal to the present value of the fixed payments, with both sides discounted along the OIS curve. For USD SOFR swaps, both legs commonly use an Actual/360 day count, though some structures apply 30/360 to the fixed leg.3Commodity Futures Trading Commission. Swap Specifications
What the Mid-Market Rate Is Used For
Pricing Corporate Debt
When a company issues a bond, the yield is often quoted as a spread over the mid-market swap rate at the matching tenor. A new five-year corporate bond might price at “swap plus 85 basis points,” meaning the yield equals the five-year mid plus 0.85%. The convention gives investors a standardized way to compare credit risk across issuers, because the swap curve strips out interest rate movement and isolates the issuer’s credit premium.
Hedging Floating-Rate Exposure
A treasurer with floating-rate debt faces uncertainty about future interest costs. Entering a swap to pay fixed and receive floating converts that variable expense into a known fixed cost. The mid-market rate is the reference point for negotiating the hedge. The actual execution rate will be slightly worse because of the dealer’s spread, but the mid establishes what fair looks like.
Mark-to-Market and Early Termination
A swap worth zero at inception gains or loses value as market rates move. If you entered a five-year swap paying 3.00% fixed two years ago and the three-year mid-market rate is now 3.50%, your swap has positive value because you’re locked in below the current market rate. The mark-to-market value is calculated by discounting the difference between your contract rate and the current mid over the remaining life of the swap.
Early termination payments work the same way. If a company wants to exit a swap before maturity, the settlement is based on the current mid-market rate for the remaining tenor. ISDA’s standardized documentation governs how these close-out amounts are determined.6ISDA. ISDA Close-out Amount Protocol
Pricing Swaptions and Other Rate Options
Swaptions, which give the holder the right to enter a swap at a future date, derive their value from the mid-market swap curve. Intrinsic value depends on where the forward mid-market rate sits relative to the strike, and the volatility of those forward rates drives the time value. Caps, floors, and other interest rate options reference the same curve as their pricing foundation.
Fair Value Accounting
Fair value accounting requires every derivative on the balance sheet to be carried at market value, and the mid-market curve is the baseline. Institutions layer on Credit Valuation Adjustments (CVA) to reflect the risk that a counterparty defaults before maturity,7Bank for International Settlements. MAR50 – Credit Valuation Adjustment Framework and Debt Valuation Adjustments (DVA) to capture their own default risk. The adjustments start from the mid value and move the number toward a figure that reflects the credit quality of both sides.
The Swap Spread and Why It Can Go Negative
The swap spread is the difference between the mid-market swap rate and the yield on a government bond of matching maturity.8Bank for International Settlements. Negative Interest Rate Swap Spreads Signal Pressure in Government Bond Markets A positive swap spread means the swap rate sits above the Treasury yield, which was historically the norm and reflected the slightly higher credit risk of a bank counterparty compared to the U.S. government.
Corporate bonds are frequently priced as a spread over the swap rate rather than over Treasuries, because the swap curve reflects the credit profile of financial institutions, which is a closer comparison for corporate issuers than sovereign risk.
At certain maturities, particularly the 30-year point, swap spreads have been persistently negative since 2008, meaning the swap rate sits below the Treasury yield. The main driver was heavy demand from pension funds and insurers to receive fixed in long-dated swaps to hedge long-duration liabilities, combined with dealer balance sheet constraints that prevented arbitrage from closing the gap.9Bank for International Settlements. An Explanation of Negative Swap Spreads – Demand for Duration From Underfunded Pension Plans If you expected swap rates to always exceed government yields, this is the exception to know about.
Where Published Mid-Market Rates Come From
ICE Swap Rate
The principal published benchmark for mid-market swap rates globally is ICE Swap Rate, formerly ISDAFIX. Administered by ICE Benchmark Administration, it represents the mid-price for the fixed leg of interest rate swaps across multiple currencies and tenors from 1 to 30 years. It has been designated a critical benchmark under UK regulation and a significant benchmark under EU regulation.10ICE Benchmark Administration. ICE Swap Rate
The benchmark is calculated using a waterfall. The first level draws on executable prices and volumes from regulated electronic trading venues. If venue data is insufficient, the second level uses dealer-to-client prices displayed electronically. A third level applies movement interpolation. Multiple randomized snapshots during a short window before each calculation guard against manipulation and short-term dislocations.10ICE Benchmark Administration. ICE Swap Rate
ICE Swap Rate serves as the exercise value for cash-settled swaptions and as the reference rate for close-out payments on early-terminated swaps. It is also used in some floating-rate bond structures and for portfolio valuation.
Professional Data Platforms
Bloomberg Terminal and Refinitiv Eikon are the dominant real-time data platforms for swap rates. They aggregate anonymous bid and ask quotes from interdealer markets and publish the mid continuously through the trading day. An official daily closing rate is established for end-of-day valuations and net asset value calculations. Some providers, such as Chatham Financial, publish selected swap rate data on their websites, though full-curve data with intraday granularity generally requires a professional terminal subscription.