Brazil's currency rose 0.9 percent after weakening more than 2 percent last week.
After posting a deficit in March, Brazil's central government reported a primary budget surplus of 9.751 billion reais ($2.72 billion) for April thanks to higher tax revenues and a decline in subsidies.
Brazil, mired in a deep recession, lost its coveted investment-grade credit rating in 2015 after years of heavy spending and steep tax breaks under now-suspended President Dilma Rousseff's administration.
Interim President Michel Temer, who has replaced Rousseff as she faces an impeachment trial, has announced a series of measures aimed at reducing the budget deficit.
Most other Latin American stocks and currencies seesawed in thin trading due to market holidays in the United States and Britain. The Chilean peso was down 0.7 percent.
Latin American markets fell on Friday after US Federal Reserve Chair Janet Yellen hinted the central bank could increase interest rates soon, reducing the allure of high-yielding bonds.
Shares of state-owned lender Banco do Brasil SA rose more than 2 percent after falling to an almost three-month low on Friday.
Brazilian Finance Minister Henrique Meirelles said on Monday the government is not in a hurry to sell shares owned by the country's sovereign fund, including about 2 billion reais ($557 million) in the lender's stock.
Meirelles had said last week the government would consider dismantling the sovereign fund, triggering a sell-off in Banco do Brasil shares.