By Bruno Federowski
SAO PAULO, June 13 (Reuters) - The Mexican peso fell to its lowest level in nearly four months on Monday, as traders sold risky emerging market assets amid a slump in oil prices and fears that Britain may vote next week to leave the European Union.
Traders also held back risky bets ahead of a U.S. Federal Reserve meeting this week, though most believe the central bank will stand pat.
The Mexican peso fell for the third consecutive day, losing 1.09 percent to 18.8350 to the dollar.
The peso has underperformed its Latin American peers for months, losing over 9 percent so far this year.
The Mexican central bank reacted in an impromptu meeting in February by hiking rates and directly selling dollars to banks.
This assuaged investors for a while, but the currency soon resumed its decline as worries mounted over the global economy and weakness in oil.
Central bank governor Agustin Carstens said last month the peso is not seeing a new speculative attack despite the recent slump, suggesting he was reluctant to make another surprise move and prompting investors to pare back bets on further policy tightening.
But yields on Mexican interest rate swaps have spiked back in the last three sessions of peso losses as investors bet Mexico's central bank could hike interest rates in its next scheduled monetary policy meeting on June 30.
Many investors use the highly liquid Mexican peso, the only Latin American currency which trades 24 hours a day, as a way to hedge their exposure to the wider region.
Nomura Securities analyst Benito Berber highlighted the risk of policies curtailing Mexico-U.S. financial flows if Donald Trump becomes president, as well as shrinking government revenues from state-controlled oil company Pemex.
"We believe that the central bank would not have sufficient tools to stabilize the currency if these shocks were to hit the economy, particularly if they occurred simultaneously," Berber wrote in a client note.
In Colombia, whose currency is also affected by oil price movements, the peso fell 0.83 percent. The real lost 1.6 percent against the dollar with Brexit and Fed jitters also hurting the currency.
However, Brazil's benchmark Bovespa stock index rose 0.48 percent thanks to a rally in shares of Ultrapar Participações SA, which gained 4.91 percent.
The country's second-biggest fuel distributor, Ultrapar's Ipiranga unit, agreed on Sunday to purchase smaller peer Alesat Combustíveis SA for 2.17 billion reais ($627 million). (Reporting by Bruno Federowski; Additional reporting by Michael O'Boyle; Editing by W Simon and Diane Craft)