7.71% in a single session. That was the gain of the Ibovespa, the main index of B3, Brazil's stock exchange in São Paulo, which closed at 206,920.66 points on Monday (5) and crossed 200,000 points for the first time in its history, according to Poder360. For anyone with money in stock funds or a private pension plan, it was like earning in a few hours what a savings account pays in about a year.

It was the first trading session after the first round of the presidential election, which ended with Senator Flávio Bolsonaro (PL) ahead of President Lula (PT), by 47.03% to 45.16% of valid votes, against what most polls had shown. The runoff is set for October 25. The dollar also fell 4.12%, to R$ 5.001, with a daily low of R$ 4.953, which tends to ease the price of imported goods and travel abroad.

During the day the euphoria ran even higher: the index hit 209,600 points around 10:40 a.m., BBC News Brasil reported. Banks led the gains, rising more than 10%: Banco do Brasil climbed 11%, Itaú 10.37%, Bradesco 13.57%, BTG Pactual 22.52% and B3 itself 22.63%, according to G1.

Understand: why the stock market soared

Investors began betting on a government more inclined to fiscal adjustment, meaning cuts in public spending to balance the country's accounts. Future interest rates tumbled as a result: the rate projected for January 2031 fell from about 14% to 12.85% per year, said Bruno Perri of Forum Investimentos to G1. When fixed income (bonds that pay interest to investors) yields less, stocks become more attractive, and the market rises.

Flávio's aides promise to cut spending equivalent to 1.5% of GDP (the total value of everything the country produces), around R$ 190 billion, the BBC reported. So far, however, the campaign has not presented a detailed breakdown of how to reach that figure.

Analysts urge caution about the euphoria. "The central point is that short-term optimism needs to turn into concrete delivery", said Gustavo Sung, chief economist at Suno Research, to G1. Sergio Vale of MB Associados told the BBC that everything will depend on who is chosen to run the Finance Ministry, and warned of the risk that a potential Flávio government spends its energy trying to free Jair Bolsonaro, his father, from prison, one of his campaign promises.