The Brazilian real led losses among Latin American currencies on Monday after an opinion poll showed the market's preferred candidate in October's presidential elections lagging far behind his rivals. The Real was down 0.76% and 15.98% in the eight months of the year.
Geraldo Alckmin, a center-right establishment politician backed by a broad centrist coalition, has only 4.9% of voting intentions, according to the survey by CNT/MDA.
Investors say bringing back Brazil's investment-grade status hinges on pursuing structural reforms to stem the growth of public debt, a scenario that is looking increasingly unlikely.
Ricardo Gomes da Silva, head of currency trading at Correparti brokerage in São Paulo, said Brazilian markets will probably sell off whenever polls show Alckmin losing favor relative to other candidates.
The nation's benchmark Bovespa stock index, however, fell only slightly as rising iron ore prices helped lift shares of miners and steelmakers, such as Vale SA and Cia Siderúrgica Nacional SA.
Also helping boost shares in CSN, as the steelmaker is known, was an announcement on Friday that it will pay 890 million reais in extraordinary dividends.
Other emerging market currencies also traded lower as investors took a cautious stance ahead of meetings between the United States and China later this week. Trade tensions between the world's top two economies have dented demand for risky assets in recent months.