The US dollar is issued by the Federal Reserve System. The Mexican peso is issued by Banco de México, whose governing law states its purpose as supplying the national economy with domestic currency and whose priority objective is to secure the stability of that currency’s purchasing power. That objective is constitutional: Article 28 of the Mexican Constitution establishes a central bank autonomous in the exercise of its functions and its administration, states that its priority objective is the stability of the purchasing power of the national currency, and provides that no authority may order the bank to grant financing. The reform took effect on 1 April 1994. In ISO 4217 the peso is MXN, numeric 484, with two minor units, matching the dollar.

The US–Mexico remittance corridor is the largest in the world by transaction count, and Banco de México publishes it in detail. Remittance income totalled US$61,791 million in 2025, a fall of 4.6% on the year, spread across 155,740 thousand individual operations at an average of US$397 each. Almost all of it converts electronically: 99.1% of 2025 remittance income arrived by electronic transfer. Banxico’s quarterly country-of-origin table shows the United States supplying the overwhelming majority of that flow. On the market side, the BIS Triennial Central Bank Survey for April 2025 put USD/MXN at 1.5% of global OTC turnover — again, a pair whose everyday significance far exceeds its trading share.

Mexico has operated a free float since 22 December 1994. Banco de México states that the exchange rate "se determina libremente en el mercado sin la intervención de las autoridades" — determined freely in the market without the intervention of the authorities — and that any operations it does carry out in the currency market are done through pre-announced mechanisms and transparent rules. Remittances enter the picture as an accounting fact as well as a market one: Banxico’s balance of payments records them in secondary income, which showed a surplus of US$61,467 million in 2025 against a current account deficit of US$8,200 million. Manufacturing exports, policy-rate differentials and broad dollar conditions supply the other side of the demand.

Mexico has an official rate with a specific legal job, and it is worth not confusing it with a market rate. Banco de México determines the FIX from an average of wholesale foreign exchange market quotes; it is the rate for settling obligations denominated in dollars but payable in the Mexican Republic. Banxico releases it from 12:00 on bank business days and publishes it in the Diario Oficial de la Federación one bank business day after determination — so the published FIX for a given determination date appears after the fact by design. For sending money, the World Bank reports Mexico as the cheapest receiving market in the G20, at 4.53% in the third quarter of 2025 against a global average of 6.36%, and its corridor data lists each provider’s exchange rate margin separately from its fee — some of those margins are negative, some fees are zero, and neither on its own tells you the total.