The Dow Jones Industrial Average increased 495.64 points, or 2.39 percent, to 21,200.55. The S&P 500 rose 28.23 points, or 1.15 percent, to 2,475.56. The Nasdaq Composite Index was down 33.56 points, or 0.45 percent, to 7,384.30.
Eight of the 11 primary S&P 500 sectors closed higher, with industrials up 5.29 percent, outpacing the rest. Communication services dropped 1.59 percent, representing the worst-performing group.
The U.S. Senate is expected to approve a 2-trillion-U.S.-dollar stimulus package later Wednesday to blunt the economic impact of COVID-19, after days of strenuous negotiations between Republicans and Democrats.
The White House and Senate leaders reached a deal early Wednesday morning on the massive stimulus package, which is aimed at cushioning the economy from the growing impact of the coronavirus outbreak.
The number of COVID-19 cases in the United States topped 60,000 as of 3:30 p.m. U.S. Eastern Time on Wednesday (1930 GMT), according to the Center for Systems Science and Engineering at Johns Hopkins University.
Wednesday's market movement followed a historic rally in the previous session, with the 30-stock index soaring more than 2,100 points, or over 11 percent, notching its biggest one-day percentage gain since 1933.