Futures for the Dow Jones Industrial Average and the S&P 500 rose less than 0.3 percent in the moments following Pelosi’s statement, which had been widely expected.
‘’Our democracy is what is at stake," Pelosi said. “The president leaves us no choice but to act.”
She said she was authorizing the drafting of articles of impeachment “sadly but with confidence and humility.”
“The president's actions have seriously violated the Constitution,” Pelosi said.
At the heart of the impeachment probe is a July call with the president of Ukraine, in which Trump pressed the leader to investigate Democrats as Trump was withholding aid to the country.
Pelosi delivered the historic announcement as Democrats push toward a vote, possibly by Christmas.
President Trump has repeatedly taken credit for driving up markets since his November 2016 election, and the Dow has climbed almost 10,000 points in that time frame.
The Associated Press contributed to this report.