Mexico’s Foreign Reserves Fall to US$255.95 Billion

MEXICO · ECONOMY

Mexico’s central bank ended September with US$2.53 billion less in reserves, and none of the drop came from defending the peso.

Mexico, a top US trading partner, saw its foreign reserves fall US$2.53 billion in September to US$255.95 billion, central bank data show. Mexico’s foreign reserves still beat the US$253.7 billion forecast, though they slipped from August’s record month-end level of US$258.48 billion.

Banco de México (Banxico), the autonomous central bank, neither bought nor sold dollars in the currency market in September. So the drop was not a defence of the peso, the currency US exporters, investors and remittance senders watch.

What the Central Bank’s Figures Show

Banxico’s statistics system puts the reserve at US$255,945.6 million at the end of September, against US$258,478.7 million at the end of August. The data were online on the central bank’s statistics site on Wednesday, 7 October.

The fall of 0.98% is the largest monthly drop since March, when reserves shed US$3.20 billion. August’s level was the highest month-end figure in a Banxico series that starts in 1996.

Mexico’s foreign reserves remain US$8.66 billion, or 3.5%, above September 2025 and US$4.07 billion above the end of 2025. The September figure is still the fifth-highest month-end level on record.

Why the Reserves Fell

Banxico tracks the money behind the change through a related measure, net international assets, which fell US$656.7 million in September. Its flow table splits that change into four sources.

Federal government operations added US$1,943.3 million, while Petróleos Mexicanos (Pemex), the state oil company, subtracted US$74.5 million. Market operations, meaning Banxico’s own dollar purchases or sales, were zero.

The biggest drag was a catch-all “other” item of minus US$2,525.6 million. Banxico says it covers net interest, changes in the dollar value of non-dollar holdings, trading results and commercial banks’ dollar deposits.

The reserve itself fell US$1.88 billion more than net international assets did. Banxico’s notes attribute such gaps to short-term and IMF liabilities, including dollar deposits held there by the government and Pemex.

Under the Bank of Mexico Law, short-term foreign-currency liabilities are subtracted when the reserve is calculated. Dollars the government parks at Banxico therefore raise net international assets without raising the reserve.

Six Weekly Declines Since the August Peak

Weekly figures show the slide began after reserves hit a record US$258,608.8 million on Friday, 21 August. El CEO, a Mexican business outlet, reported that level as a new all-time high at the time.

Reserves then fell for six straight weeks, reaching US$256,039.8 million on Friday, 2 October. The latest weekly drop was US$503 million.

The 2 October level is US$94.2 million above the month-end figure, because Banxico’s weekly data use Friday balances. September ended on a Wednesday.

What It Means for You

For holders of Mexican government and Pemex dollar bonds, reserves are a gauge of the country’s ability to meet foreign-currency obligations. El CEO describes them in similar terms.

The September dip is under 1%, and reserves are still higher than a year ago. Nothing in the data points to the central bank spending reserves to prop up the currency.

For US companies, travellers and families sending money to Mexico, the exchange rate matters more than the reserve level. Banxico’s FIX reference rate was 17.9780 pesos per US dollar on Wednesday, 7 October.

Banxico’s data record no dollar sales or purchases in the market since January 2017. The peso’s moves therefore reflect supply and demand, not central bank selling.

What Is Not Known

Banxico’s tables do not split the US$2,525.6 million “other” item into valuation, interest and bank deposits. It is therefore unclear how much of the fall came from currency or bond price moves.

The data also do not say why federal government flows turned positive in September, after minus US$545.1 million in August. The exact hour Banxico first posted the month-end figures could not be confirmed.

What Comes Next

Banxico publishes reserve data every week, so the next reading will show whether the six-week slide continues. The October month-end figure is expected in early November.

One monthly decline does not mean Mexico is drawing down its reserves to support the peso. The central bank’s market operations stood at zero in September.

Frequently Asked Questions

How much foreign currency does Mexico’s central bank hold?

Mexico’s central bank held US$255.95 billion in international reserves at the end of September. That was down US$2.53 billion from August’s record month-end level.

Did Mexico sell dollars to support the peso in September?

No. Banxico recorded zero market operations in September, and its data show no such operations since January 2017.

What explains the fall in Mexico’s reserves?

Banxico’s flow data show a negative “other” item of US$2.53 billion, which includes valuation changes, interest and bank deposits. Government operations added US$1.94 billion, while Pemex subtracted US$74.5 million.

Why do Mexico’s reserves matter to Americans?

Mexico is a top US trading partner, and its reserves back the peso and foreign-currency debt payments. The peso’s value affects US exporters, investors, travellers and remittance senders.

When is the next update?

Banxico publishes reserve figures every week. The October month-end number is expected in early November.

Sources: Banco de México, SIE table CF169 (reserve balances and flows); Banco de México, SIE table CF139 (monthly international assets); Banco de México, SIE table CF106 (weekly reserves); Banco de México, SIE table CF102 (FIX exchange rate); El CEO (all accessed 8 October 2026).