"Everyone was caught by surprise," an analyst told Bloomberg. "The market will reprice everything."
The result upended about $6 billion in corporate equity sales that had been lined up for after the election. Brazilian stocks had surged after Bolsonaro's first-round win, when he pledged to trim deficit spending.
Both candidates, however, closed out the campaign's final hours promising expensive new subsidies, highlighting the political difficulty of reining in public debt, which has increased under Lula by 10 percentage points to more than 82% of GDP.
Bolsonaro has challenged the election result, adding further pressure on Brazil's real.
