Why the official peso-dollar rates differ most on the days the peso moves

Three official sources give a peso-dollar rate for each working day: Banco de México, the central bank of Mexico.Source: Deutsche Bundesbank, Metadata on the Exchange rate statisticsOpens in a new tab's The peso-dollar rate Banco de México publishes from 12:00 every banking day. It appears in the Diario Oficial de la Federación a banking day later and settles obligations in dollars payable in Mexico.Source: Banco de México, Tipos de cambio diariosOpens in a new tab, 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 rate at noon in New York for cable transfers payable in a foreign currency, which the Federal Reserve Bank of New York certifies for customs purposes.Source: Board of Governors of the Federal Reserve System, Foreign Exchange Rates - H.10Opens in a new tab, and a The exchange rate between two currencies, expressed through a third currency.Source: IATE, the terminology database of the European Union, cross rateOpens in a new tab from 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. The ECB's is set hours before the other two, and on the days the peso moves most, it differs from them most.

When each rate is set

The ECB determines its reference rates daily around 14:10 CETSource: European Central Bank, Framework for the euro foreign exchange reference ratesOpens in a new tabGo to the list of sources; its press release of December 7, 2015 describes a point-in-time snapshot at 14:15 CETSource: European Central Bank, ECB introduces changes to euro foreign exchange reference ratesOpens in a new tabGo to the list of sources. Either time is before 8:00 in Mexico City. The peso-dollar cross rate is the euro's peso rate divided by its dollar rate.
Since April 22, 1996, Banco de México has set the FIX from quotes taken in three periods, de las 9:00 a las 9:59 horas, de las 10:00 a las 10:59 horas, y de las 11:00 a las 12:00 horasSource: Banco de México, Determinación del tipo de cambio para solventar obligaciones denominadas en moneda extranjera pagaderas en la República MexicanaOpens in a new tabGo to the list of sources (from 9:00 to 9:59, from 10:00 to 10:59, and from 11:00 to 12:00); until April 22, 1997 the third ran from 11:00 to 11:15. 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 keeps the three periods and refers its times to the huso horario de la Ciudad de MéxicoSource: Banco de México, Circular 3/2012Opens in a new tabGo to the list of sources (Mexico City time). FXtab's article on the FIX describes how it is computed and what it is for.
The Federal Reserve'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 rates are noon buying rates in New YorkSource: Board of Governors of the Federal Reserve System, Foreign Exchange Rates - H.10Opens in a new tabGo to the list of sources: 10:00 or 11:00 in Mexico City, during the FIX's second or third period.

What the history shows

On each date two of the rates share, FXtab measures the gap between them. The gap grows with the FIX's change from the FIX before (in the table, Fed stands for the Federal Reserve's rate and ECB for the ECB's cross rate):Figures computed by FXtab from:Banco 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 tabBoard of Governors of the Federal Reserve System, G.5/H.10 - Foreign Exchange RatesOpens in a new tabWorld Bank, Remittance Prices WorldwideOpens in a new tabGo to the list of sources

Median gap between the official peso-dollar rates on the same date, by the FIX's change from the FIX before
Rates	From	FIX changed under 0.25%	FIX changed over 1%
FIX and Fed	April 22, 1996	0.045% (2,878 days)	0.100% (741 days)
FIX and ECB	January 2, 2008	0.161% (1,654 days)	0.511% (629 days)
Fed and ECB	January 2, 2008	0.181% (1,580 days)	0.550% (612 days)

On the 629 days the FIX changed more than 1%, the ECB's cross rate lay on the side of the FIX before, below the FIX on a day it rose and above it on a day it fell, on 82.7% of them. The Federal Reserve's rate, taken during the FIX's periods, did so on 48.6% of its 741 such days, close to half.Figures computed by FXtab from:Banco 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 tabBoard of Governors of the Federal Reserve System, G.5/H.10 - Foreign Exchange RatesOpens in a new tabWorld Bank, Remittance Prices WorldwideOpens in a new tabGo to the list of sources

By year, the median gap was widest in 2020 (0.351%), 2009 (0.321%) and 2018 (0.306%) between the FIX and the ECB's cross rate, and in 2009 (0.093%), 2020 (0.087%) and 2018 (0.082%) between the FIX and the Federal Reserve's rate. The largest gap between the FIX and the ECB's cross rate was 5.17%, on October 23, 2008; between the FIX and the Federal Reserve's rate, 1.41%, on October 24, 2008.Figures computed by FXtab from:Banco 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 tabBoard of Governors of the Federal Reserve System, G.5/H.10 - Foreign Exchange RatesOpens in a new tabWorld Bank, Remittance Prices WorldwideOpens in a new tabGo to the list of sources

What it means for your money

The median gaps between the official rates stay below 1%. What the services that send money charge varies more. In the first quarter of 2025, 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 surveyed 46 services from 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 for sending 200 US dollars from the United States to Mexico. Their 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 ran from -1.63% to 17.50%, with a median of 4.72%. Their 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, ran from -1.71% to 3.36%, with a median of 1.35%; 14 services had 1% or less.Figures computed by FXtab from:Banco 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 tabBoard of Governors of the Federal Reserve System, G.5/H.10 - Foreign Exchange RatesOpens in a new tabWorld Bank, Remittance Prices WorldwideOpens in a new tabGo to the list of sources A negative FX margin means the service applied a rate better than the interbank exchange rate. For the peso and the dollar, FXtab shows the FIX, and its Check a quote computes the total cost of a quote you have against it.

Sources

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