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Building Swap Rates from Eurodollar Futures-Implied Forward Rates

Article Quant Q&A · Author: drawar

Summary

The document explains how Eurodollar futures can provide a strip of implied forward rates and how those rates can be used to construct a fixed-for-floating interest rate swap rate. For payment dates, the forward floating rates are weighted by discount factors and accrual fractions; the par fixed rate is the ratio of the discounted floating-leg value to the discounted fixed-leg annuity. It illustrates the calculation for a quarterly swap using two forward periods and discount factors.

The answer clarifies that the cited table represents a one-year swap beginning around the June futures expiration, with quarterly payments against three-month LIBOR. The same valuation framework can accommodate a deferred start by changing the schedule dates, and other accrual frequencies can be handled with the corresponding periods. However, Eurodollar futures directly reference three-month LIBOR. Treating semiannual LIBOR as compounded quarterly LIBOR is only an approximation; modern multi-curve practice recognizes distinct curves and risks for different tenors.

Key ideas

  • The par swap rate equates the present value of fixed and floating payments.
  • Discount factors and accrual fractions weight each forward rate in the swap calculation.
  • Eurodollar futures imply forward rates for three-month LIBOR periods.
  • Deferred swaps can be valued by applying the formula to their own effective and payment dates.
  • Quarterly rates should not be assumed to represent semiannual LIBOR without accounting for tenor-specific curves.

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Full text
# Calculate interest rate swap curve from Eurodollar futures price


# Calculate interest rate swap curve from Eurodollar futures price












So I was reading Robert McDonald's "Derivatives Markets" and it says Eurodollar futures price can be used to obtain a strip of forward interest rates. We can then use this to obtain the implied forward LIBOR term structure and build the interest rate swap curve. The book also provides a concrete example to illustrate its point but somehow I cannot seem to understand it.

There was no assumption about the terms of the swap, so I was kinda confused. Is it correct to say that the swap rates calculated in the table are based on an interest rate swap that starts in June with quarterly payments? Moreover, can this method be extended to determine the swap rate on a deferred interest rate swap, i.e., one that instead starts on Sep/Dec with payments being made semi-annually/annually? Thank you!

## Answer by Gordon (score 3)

https://quant.stackexchange.com/a/29690

Consider a fixed-for-floating swap with reset dates $T_0, \ldots, T_{n-1}$ and payment dates $T_1, \ldots, T_n$, where $0<T_0 < \cdots < T_n$. We assume that the swap exchanges the floating rate payments $L(T_{i-1}; T_{i-1}, T_i)\Delta T_i$ and the fixed rate payments $K\Delta T_i$, for $i=1, \ldots, n$, where $\Delta T_i = T_i -T_{i-1}$.

The value of the swap at time $t$, where $0 \leq t \leq T_0$, is given by \begin{align*} \sum_{i=1}^n L(t; T_{i-1}, T_i)\times \Delta T_i\times P(t, T_i) - K \sum_{i=1}^n P(t, T_i)\times \Delta T_i,\tag{1} \end{align*} where $P(t, u)$ is the price (i.e., zero price) of a zero-coupon bond with maturity $u$ and unit notional. The forward swap rate $s$ is the rate $K$ such that the swap value given by $(1)$ is zero, that is, \begin{align*} s = \frac{\sum_{i=1}^n P(t, T_i) \times L(t; T_{i-1}, T_i) \Delta T_i }{\sum_{i=1}^n P(t, T_i) \times \Delta T_i}. \end{align*} For a quarterly resetting frequency, that is, $\Delta T_i=\frac{1}{4}$, then $\frac{1}{4}L(T_{i-1}, T_i)$ is the quarterly interest rate. Moreover, the quarterly swap rate is given by \begin{align*} \frac{s}{4} = \frac{\sum_{i=1}^n P(t, T_i) \times \frac{1}{4}L(t; T_{i-1}, T_i)}{\sum_{i=1}^n P(t, T_i)}.\tag{2} \end{align*}

For the given example, we have that $n=2$, $P(t, T_1) = 0.998566$, $P(t, T_2) = 0.99655$, $\frac{1}{4}L(t; T_0, T_1) = 0.0014358$, and $\frac{1}{4}L(t;T_1, T_2) = 0.0020222$. Based on Formula $(2)$, the quarterly swap rate is given by \begin{align*} \frac{s}{4} = \frac{0.998566 \times 0.0014358 + 0.99655 \times 0.0020222}{0.998566+0.99655} = 0.17287\,\%. \end{align*} The computation for swap rate with semi-annual or annual accrual frequency can be proceeded analogously. Moreover, you can set $T_0$ to any date you like, for example, September or December, as you mentioned.

## Answer by Alex C (score 3)

https://quant.stackexchange.com/a/29697

To answer the first question directly, the swap in question is a 1 Year swap of a fixed rate vs 3 month Libor. The swap starts in Mid-June (the date of the ED futures expiration) and goes until the next June. There are 4 quarterly payments.

To understand things better, look carefully at Table 8.4 and see how the three columns on the right are computed from information in the Futures Prices column. Note how the ED price for June is used to calculate an implied rate which is then written down in the Sep row of the table. And so forth. (It could be fun to reproduce these calculations in a spreadsheet).

This process can be used to value a swap of any tenor, or a deferred swap. Strictly speaking it should only be used to value swaps with quarterly payments of 3-month Libor. That is what the ED futures are tied to. (You could approximate semi-annual by compounding quarterly interest rates, but that's not recommended because a modern (post 2008) approach says 3-month Libor and 6-month Libor should be taken from different curves and you should not approximate one from the other, they are inherently different in liquidity and risk).

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.