Why dollar debts in Mexico are paid at the FIX

In Mexico, a debt written in US dollars is paid in pesos, and the law leaves the rate to Banco de México, the central bank of Mexico.Source: Deutsche Bundesbank, Metadata on the Exchange rate statisticsOpens in a new tab. The rate it publishes for that purpose is the FIX.

Which rate, and what it is for

Article 8 of the Mexico's Monetary Law, which makes the peso the unit of the country's monetary system.Source: Cámara de Diputados del H. Congreso de la Unión, LEY MONETARIA DE LOS ESTADOS UNIDOS MEXICANOSOpens in a new tab says that foreign currency is not Money that a creditor is bound by law to accept in payment of a debt.Source: IATE, the terminology database of the European Union, legal tenderOpens in a new tab in Mexico, save where a law provides otherwise, and that obligations to pay foreign currency, contracted inside or outside the country to be paid in it, se solventarán entregando el equivalente en moneda nacional, al tipo de cambio que rija en el lugar y fecha en que se haga el pagoSource: Cámara de Diputados del H. Congreso de la Unión, LEY MONETARIA DE LOS ESTADOS UNIDOS MEXICANOSOpens in a new tabGo to the list of sources (are settled by delivering the equivalent in national currency, at the exchange rate in force at the place and date of payment). That rate se determinará conforme a las disposiciones que para esos efectos expida el Banco de MéxicoSource: Cámara de Diputados del H. Congreso de la Unión, LEY MONETARIA DE LOS ESTADOS UNIDOS MEXICANOSOpens in a new tabGo to the list of sources (is determined under the provisions Banco de México issues for the purpose).

Banco de México's provisions, Banco de México's provisions on the operations of credit institutions, that is, banks.Source: Banco de México, Circular 3/2012Opens in a new tab, name the day: dollar obligations are paid al tipo de cambio que el Banco de México publique en el Diario Oficial de la Federación el Día Hábil Bancario inmediato anterior a aquel en que se haga el pagoSource: Banco de México, Circular 3/2012Opens in a new tabGo to the list of sources (at the rate Banco de México publishes in the The official gazette of the Mexican government, which publishes federal laws, decrees, regulations, circulars and other acts.Source: Cámara de Diputados del H. Congreso de la Unión, LEY DEL DIARIO OFICIAL DE LA FEDERACIÓN Y GACETAS GUBERNAMENTALESOpens in a new tab on the A day on which Mexico’s banks are not required to close their doors or suspend operations, under the rules of the Comisión Nacional Bancaria y de Valores.Source: Banco de México, Circular 3/2012Opens in a new tab before the payment). A payment made today therefore uses a FIX Banco de México set on an earlier day.

Each banking day, Banco de México takes quotes for dollars to be settled two banking days later from the dealing platforms, in three periods: de las 9:00:00 a las 9:59:00 horas; de las 10:00:00 a las 10:59:00 horas, y de las 11:00:00 a las 12:00:00 horasSource: Banco de México, Circular 3/2012Opens in a new tabGo to the list of sources. In each period it picks a moment at random and averages the highest buying quote and the lowest selling quote; the FIX is el promedio aritmético de los tres tipos de cambio de equilibrioSource: Banco de México, Circular 3/2012Opens in a new tabGo to the list of sources (the arithmetic mean of the three equilibrium rates), to four decimals.

What the history shows

Banco de México's daily peso-dollar series begins on April 19, 1954. The day before, its annual report says, the government had announced el establecimiento de un nuevo tipo de cambio para el peso, que a partir de esa fecha sería de $12.50 por dólar norteamericano, devaluando su moneda en un 30.8%Source: Banco de México, Informe anual 1954Opens in a new tabGo to the list of sources (a new exchange rate for the peso, from that date $12.50 per US dollar, devaluing its currency by 30.8%). The series shows the rate unchanged on 5,837 days, to August 31, 1976;Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources the report of that year says the peso abandonó el 31 de agosto el tipo de cambio fijo de 12.50 pesos por dólar, y flotóSource: Banco de México, Informe anual 1976Opens in a new tabGo to the list of sources (abandoned the fixed rate of 12.50 pesos per dollar on August 31, and An exchange rate allowed to move with supply and demand in the foreign exchange market.Source: IATE, the terminology database of the European Union, floating exchange rateOpens in a new tab).

The series moves by more than 10% in a day 23 times, all between 1976 and 1995: 3 times in 1976 and 1977, the first 64% on September 1, 1976; 7 times in 1982, the largest 113% on December 20, 1982; 7 times from 1985 to 1987; and 6 times from December 20, 1994 to March 10, 1995. The 1994 report records the decision to pasar a un régimen de flotación con efectos a partir del 22 de diciembreSource: Banco de México, Informe anual 1994Opens in a new tabGo to the list of sources (to move to a floating regime with effect from December 22); that day the series rose 22.3%.Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources

The series is in today's pesos. Of the change on January 1, 1993, the 1992 report says: La nueva unidad monetaria equivale a mil pesos anteriores y conserva el nombre de “peso”Source: Banco de México, Informe anual 1992Opens in a new tabGo to the list of sources (The new monetary unit equals a thousand former pesos and keeps the name “peso”). The 12.50 of 1954 appears as 0.0125.Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources

What it means for your money

Three official sources give a peso-dollar rate every working day, each at its own hour:

the FIX, from November 12, 1991 in FXtab's series;Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources
the The Federal Reserve, the central bank of the United States.Source: Deutsche Bundesbank, 1973: The end of Bretton Woods When exchange rates learned to floatOpens in a new tab's The Federal Reserve Board's weekly release of daily exchange rates of major currencies against the US dollar.Source: Board of Governors of the Federal Reserve System, Foreign Exchange Rates - H.10Opens in a new tab rate, noon buying rates in New York for cable transfers payable in the listed currenciesSource: Board of Governors of the Federal Reserve System, Foreign Exchange Rates - H.10Opens in a new tabGo to the list of sources, certified by the Federal Reserve Bank of New York for customs purposesSource: Board of Governors of the Federal Reserve System, Foreign Exchange Rates - H.10Opens in a new tabGo to the list of sources, from November 8, 1993;Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources
the The European Central Bank, which began work on 1 June 1998; its Governing Council decides the monetary policy of the euro area.Source: Deutsche Bundesbank, TimelineOpens in a new tab's The euro's rates the ECB publishes every working day for information only, based on a concertation between central banks around 14:10 CET.Source: European Central Bank, Euro foreign exchange reference ratesOpens in a new tab, from which a peso-dollar cross rate follows by dividing the euro's peso rate by its dollar rate. The ECB sets them around 14:10 CETSource: European Central Bank, Framework for the euro foreign exchange reference ratesOpens in a new tabGo to the list of sources and says they are not intended to be used in any market transactionsSource: European Central Bank, Framework for the euro foreign exchange reference ratesOpens in a new tabGo to the list of sources; its peso rate is a reference rate from January 2, 2008.Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources

On the same day the three agree closely. The Federal Reserve's rate is within 0.5% of the FIX on 98.8% of the 7,981 days both have, with a median gap of 0.055%; the largest, 2.88%, was on October 26, 1995. The ECB's cross rate is within 0.5% on 80.8% of 4,680 days, with a median gap of 0.228%; its largest, 5.17%, was on October 23, 2008.Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources

The rate a sender pays is another matter. The The World Bank, which provides low-interest loans, credits and grants to developing countries.Source: IATE, the terminology database of the European Union, World BankOpens in a new tab's survey of sending 200 US dollars from the United States to Mexico found a median FX margin, the difference between the exchange rate a provider applies and the The exchange rate in the interbank market, where banks trade currencies with each other.Source: Deutsche Bundesbank, GlossaryOpens in a new tab, of 1.35% in the first quarter of 2025, down from 1.9% in the second quarter of 2016, and a median What a sender pays in all to send money: the fees plus the margin of the provider's exchange rate over the interbank exchange rate.Source: United Nations, SDG indicator metadata, Indicator 10.c.1: Remittance costs as a proportion of the amount remittedOpens in a new tab of 4.72%, against 4.67% then (15 A business that sends money for its customers for a price, directly or through agents, such as a bank or a money transfer operator.Source: United Nations, SDG indicator metadata, Indicator 10.c.1: Remittance costs as a proportion of the amount remittedOpens in a new tab in 2025). Sending money from the United States to Mexico is the largest flow between two of FXtab's currencies in the World Bank's Bilateral Remittance Estimates for 2021: 52.6 billion US dollars.Figures computed by FXtab from:Banco de México, Serie histórica diaria del tipo de cambio peso-dólarOpens in a new tabBanco de México, Tipo de cambio para solventar obligaciones denominadas en dólares de los EE.UU.A., pagaderas en la República Mexicana (FIX)Opens in a new tabEuropean Central Bank, Euro foreign exchange reference ratesOpens in a new taband 3 moreGo to the list of sources FXtab's Check a quote computes the total cost of a quote you have in the same way, against the day's official rate.

Sources

Figures as of September 25, 2026, computed by FXtab from these sources; translations from Spanish are FXtab's.