This could ruin one popular 'long Trump' trade

An employee inspects sheets of Mexican hundred pesos notes at the Banco de Mexico printing factory in Mexico City, Mexico.
Susana Gonzalez | Bloomberg | Getty Images
An employee inspects sheets of Mexican hundred pesos notes at the Banco de Mexico printing factory in Mexico City, Mexico.

Hedge funds have had a good run shorting the Mexican peso, but that country's central bank may be about to muddle what's been a favorite 'long Trump" play.

Donald Trump's anti-immigration and anti-NAFTA stances have made shorting the currencies of Mexico and Canada a no-brainer trade, particularly if you think he will win the White House.

This is what could change the outcome for investors gaming the peso.