To determine the equivalent position for F-TIIE futures, the Mexican peso/U.S. dollar exchange rate is required in order to convert the $1000 basis point value to a Mexican peso value. The price of a CME Group Mexican Peso FX futures contract can be used to do this. Prices for the Mexican Peso futures are quoted in terms of U.S. dollars per peso. Let’s establish a starting position with a futures price of U.S. $0.0500 per peso, which is equivalent to an FX rate of 20 pesos per dollar. The basis point value of the F-TIIE futures is 200 Mexican pesos. The number of F-TIIE futures required can be calculated as follows:

Our spread position is therefore short 24 1-Month SOFR futures, long 100 F-TIIE futures. The interest rate differential that has been locked in is 5.735%.

At this point, the FX exposure of this position is zero – the exposure is limited to movements in the two interest rates. As the number of F-TIIE futures has been calculated using the FX rate, should the FX rate change, this will affect the hedge ratio and F-TIIE futures may need to be bought or sold in order to maintain equivalent dollar exposure.

An FX exposure will arise should the interest rates, and therefore, the futures prices change.

Let’s imagine that interest rates change in both currencies. 1-Month SOFR decreases 0.50% and F-TIIE decreases 1.00%. The rate differential has narrowed, and therefore, the spread trade should yield a positive return. 1-Month SOFR futures prices have fallen 50 basis points – with each basis point valued at $41.67 and 24 lots held, this equates to a loss of U.S. $50K. F-TIIE futures prices have fallen 100 basis points – each basis point is valued at MXN 200 and with 100 lots held, the gain on this leg of the trade equates to MXN 2M. Assuming the FX rate is unchanged, this is equal to a gain of U.S. $100K. For the strategy as a whole, the net gain is U.S. $50K or MXN 1M ‒ depending on your base currency.

This position now has an FX exposure. Assuming the interest rate spread position is kept open, the FX risk can be hedged with CME Group Mexican Peso futures.

Whilst the net gain on the spread trade is U.S. $50K, the structure of the FX hedge depends on two different data points. Firstly, the hedge requirement will depend on the base currency of the trader.  If the base currency is U.S. dollars, then the gain made on the F-TIIE futures measured in pesos contains the FX risk. The loss on the 1-Month SOFR futures is measured in U.S. dollars, and therefore, has no FX risk for the trader. If, however, the trader’s base currency is Mexican peso, then the loss made on the 1-Month SOFR position contains the FX risk.

Secondly, the hedge requirement will depend on whether the exposure that creates the FX risk is a gain or a loss. For example, an increase in the USD/MXN FX rate (i.e. the number of Mexican pesos per U.S. dollar) will increase the MXN value of a U.S. dollar gain but will also increase the MXN value of a U.S. dollar loss. Each of these outcomes has a different desirability and each would require a different hedging strategy.

In our example, let’s first take a trader with the U.S. dollar as a base currency. The FX exposure relates to the MXN 2M gain on the F-TIIE futures. The prevailing FX rate, as observed in the MXN/USD FX futures price, is 0.0500 U.S. dollars per Mexican peso. If this value were to fall, the dollar value of the gain would be less. This outcome could be hedged by selling FX futures. Each MXN/USD FX futures contract has a size of MXN 500K. Therefore, hedging the position requires four FX futures.

Alternatively, let’s look at a trader with the Mexican peso as a base currency. The FX exposure relates to the U.S. $50K loss made on the 1-Month SOFR futures. If the prevailing FX rate of 0.0500 U.S. dollars per Mexican peso were to fall, this loss as measured in pesos would increase. This outcome could be hedged by selling FX futures. In this case, hedging the position would require two FX futures.

We can see what happens when the FX rate falls to 0.0480 (equivalent to MXN 20.833 per U.S. dollar).

For the U.S. dollar-based trader, the fall in the MXN/USD rate has reduced the value of F-TIIE futures gain by U.S. $4K. To compensate, the short position in MXN/USD futures has gained U.S. $4K.

For the Mexican peso-based trader, the fall in the MXN/USD rate has increased the peso value of the loss on the 1-Month SOFR futures by MXN 41,670. At the updated prevailing exchange rate, the U.S. $2,000 gain on the short FX futures position equates to a gain of MXN 41,667 ‒ effectively offsetting the additional loss on the SOFR position.

CME Group MXN/USD futures are an effective hedging tool for the FX risk that is present in cross-currency interest rate spread trades. The hedging requirement depends on the size and direction of the gains and losses on interest rate futures and the base currency of the trader. As this position is dynamic, the FX hedging requirement should be re-assessed frequently.