U.S. stocks closed at all-time highs on Monday, as investors awaited a vote on tax reform.

The Dow Jones Industrial Average soared 140.46 points, or 0.57 percent, to 24,792.20. The S&P 500 rose 14.35 points, or 0.54 percent, to 2,690.16. The Nasdaq Composite Index was up 58.18 points, or 0.84 percent, to 6,994.76.

House and Senate Republicans are planning to pass a package this week, with major elements including lower corporate and top individual tax rates.

U.S. President Donald Trump told reporters Friday morning: "I think that we are going to be in a position to pass something as early as next week, which will be monumental."

Media reported Congress is expected to vote as early as Tuesday on a plan that would slash the federal corporate tax rate to 21 percent from 35 percent.

"The focus of this tax plan is obviously to improve business conditions. That is no secret, and should not be looked at as a negative," said Stephen Guilfoyle, president of Sarge986 LLC, on Monday.

U.S. equities have posted solid gains and notched record highs several times since the Election Day, partially boosted by expectations of lower corporate taxes.

U.S. stocks witnessed solid gains for the last week, as investors digested the Federal Reserve's decision to hike interest rates while anticipating details of a Republican tax bill.