The Russell 2000, which tracks small-cap stocks, hit a record high on Wednesday and is up 1.7 percent this week. Small caps tend to benefit more from the tax cut as most get their revenues domestically
The major indexes were coming off a bifurcated session in which sharp gains in bank shares were offset by a rollover in tech stocks.
Tech was "being used as a source of funds for investors wishing to increase positions in sectors more likely to benefit from a potential tax reform," said Michael Shaoul, chairman and CEO of Marketfield Asset Management.
Thursday also marked the last trading day of November. The Dow notched its first eight-month winning streak since 1995. The S&P 500, meanwhile, posted its longest monthly winning streak since 2007 at eight. The Nasdaq composite also closed higher for the month.
Wall Street also looked to Vienna as OPEC members and other oil-producing countries agreed to extend production cuts until the end of 2018. Crude prices rose slightly to settle at $57.40 per barrel on Thursday.
In corporate news, Kroger jumped more than 6 percent after the company forecast strong same-store sales for the four quarter and posted better-than-expected earnings.
Meanwhile, Costco shares climbed 3.9 percent after the company reported a 7.9 percent rises in same-store sales for November.
HCA Healthcare jumped 6.1 percent after analysts at JPMorgan singled the stock out as a tax-cut play.
Correction: A previous version of this story misstated the S&P 500 had its best day since March 1.