Most stock markets in the region fell, tracking declines in Wall Street triggered by the losses in oil. But most currencies remained in positive territory, with investors still chasing higher yields amid prospects of rock-bottom interest rates abroad and a gradual but sturdy global economic recovery.
Oil prices slid nearly 2 percent after a surprise build in US inventories reinforced concerns about global oversupply.
Brazil's real posted fresh one-year highs close to 3.10 per US dollar but reduced gains in early afternoon trade. The currency rose for the seventh straight trading day, while Colombia's peso posted its sixth daily gain.
Also weighing on some regional stock indexes was a batch of bearish corporate reports.
Shares in builder Cyrela SA were the biggest losers in Brazil's benchmark Bovespa stock index after the company reported a 62 percent drop in second-quarter income.
But stocks in Gerdau SA rose 3 percent following its results. The steelmaker posted higher earnings in the second quarter compared to the first, as well as lower debt ratios.