The Brazilian real touched a five-month low on Wednesday on expectations the country's central bank will leave its policy rate unchanged, while other Latin American currencies sank on uncertainty about the outcome of next week's US elections.

The real slipped 0.9% to fall for the fourth straight day as Brazil's central bank was seen leaving its benchmark Selic rate at a record low of 2.0% later in the day.

Brazil's currency was among the worst performing emerging market units this year, falling 30%, as fears remained about the country's public finances.

"The extension of the budget deficit in an effort to fight the effects of the pandemic is limiting the central bank's scope to cut rates further," said Melanie Fischinger, FX and emerging markets analyst at Commerzbank.

Most emerging market currencies weakened against the dollar as traders hedged against the possibility of a Democratic sweep in the Nov. 3 US presidential election. Gauges measuring expected swings in foreign exchange markets rose on Wednesday, with one-week contracts that cover the vote reaching their highest levels in nearly seven months.

Surging coronavirus cases also kept risk sentiment at bay, while tumbling oil prices pushed currencies of crude-exporters including Mexico and Colombia lower.

The Mexican peso tumbled more than 1%, while Colombia's peso slipped 0.7%.

Chile's peso bucked an eight-day winning streak to fall 0.3%, with local investors focusing on the country's path to reframe its constitution.

Argentina auctioned a dollar-linked bond and other debt for a total of about $3.18 billion on Tuesday, the economy ministry said, as the government looks to ease pressure on the battered peso currency. The country's peso currency was flat.

The MSCI's index for Latin American stocks tumbled 3.7%, on track for its worst one-day percentage decline in over one month.

Sao Paulo stocks tumbled 2.6%, with heavyweight miner Vale falling 2%.

Santiago stocks dropped 1.6%, weighed by a 2% decline in shares of Banco Santander-Chile after it expected to show a fall in quarterly revenue.