Forex trading tax in Mexico: how ISR applies to your profit

What gets taxed

Mexico taxes its residents on worldwide income: a person who is tax-resident in Mexico pays income tax (ISR) on all income, whatever the location of the source of wealth.^[1] Profit from forex or CFD trading is therefore taxable in Mexico whether the broker is Mexican or offshore, and whether or not the money is brought back into the country. What is taxed is the realised result of closed positions, not the movement of funds between your bank and the broker: an open position with floating profit is not yet income, and withdrawing capital you deposited yourself is not income either.

How the profit is classified

Forex and CFDs are financial derivative operations. The Federal Tax Code defines an operación financiera derivada to include contracts referred to the exchange rate of a currency, or to an index, price or rate, that are settled by paying the difference between the value agreed at the outset and the value on set dates.^[2] That is exactly how a retail forex or CFD position works. For an individual, the gain on these operations is “other income” taxed under Article 146 of the Income Tax Law: the gain is worked out at the close, the maturity, of each operation and accumulated in the annual return.^[1]

The rate

The gain is added to your other income for the year and taxed on the ordinary progressive scale for individuals, the annual tarifa of Article 152, which runs from 1.92% on the lowest band up to a top marginal rate of 35%.^[1] Because the profit is stacked on your salary and any other income, the rate that bites is the one for your total for the year, not a flat trading rate. The 35% band begins at annual taxable income of roughly 3.9 million pesos; the exact thresholds are set in Article 152, are updated for inflation, and SAT publishes the current tarifa.^[1]

No one withholds it for you

When a Mexican casa de bolsa or bank takes part in a derivative operation, it withholds 25% of the month's gain as a provisional payment of the tax.^[1] A broker abroad is neither, so it withholds nothing: no Mexican tax is taken out at source, and calculating and paying the ISR is your own responsibility. The gain is settled in the annual return; there is no separate form for foreign income, it goes into the ordinary Declaración Anual.^[1]

Pesos, and keeping records

The tax is worked out in pesos. Amounts in a foreign currency are converted at the exchange rate at which the currency was bought or, failing that, at the rate the Banco de México publishes in the Official Gazette for the day before the income accrues.^[2] The peso figure is what enters the return, so the exchange rate itself moves the taxable amount. Keep the broker's statements, including for losing years: a record of deposits, trades and withdrawals is what backs up the calculation if SAT asks.

How and when to declare

Individuals who earn income in a calendar year file the annual return, the Declaración Anual, in April of the following year.^[1] Foreign trading profit goes there together with the rest of your income, and is filed and paid through SAT's online channels. So profit made in 2026 is declared and paid in April 2027.

Losses and tax paid abroad

A loss on these operations is not simply lost, but its use is narrow: under Article 146 a loss can only be set against gains or interest of the same kind, and where a month's loss exceeds the gain the excess carries to the following months of the same year.^[1] If income tax was withheld in another country on the same income, a resident can generally credit it against the Mexican ISR, capped at the Mexican tax on that income.^[1] Forex and CFD brokers do not normally withhold tax on trading gains, so for most traders this last point does not arise.

How SAT finds out

An account abroad is not invisible to SAT. Mexico takes part in the OECD automatic exchange of financial-account information, the Common Reporting Standard (CRS);^[3] the obligation on financial institutions to identify and report account holders resident elsewhere is written into Article 32-B Bis of the Federal Tax Code.^[2] Foreign institutions report to their own authority, which passes the data to SAT once a year: the account holder, the account number and balance, and interest, dividends and the proceeds from selling financial assets.^[4] Mexico has exchanged since 2017, when SAT received data from 38 jurisdictions in its first round, and the network covers the financial centres where brokers and banks sit.^[4] CRS is how SAT checks, not what makes the profit taxable: the duty to declare comes from the residence rule, whether or not SAT already holds the data.