* Trump tax plan outlined on Wednesday
* Alphabet, Amazon, Microsoft due to report after the bell
* Under Armour jumps on smaller-than-expected loss
* Futures up: Dow 32 pts, S&P 3 pts, Nasdaq 9.5 pts (Adds details, comments, updates prices)
By Yashaswini Swamynathan
April 27 (Reuters) - U.S. stocks were on track to open slightly higher on Thursday amid a flood of quarterly earnings reports, while investors assessed President Donald Trump's tax reform plan.
The one-page plan, unveiled on Wednesday, proposed deep tax cuts for many businesses, but offered no detail on how it would be paid for without increasing the deficit.
U.S. stocks snapped a two-day rally to end lower on Wednesday after the plan was unveiled. The prospects of hefty tax cuts have been a major driver of the post-election rally since November.
"Yesterday, you saw some selling but it didn't develop into an outright heavy pressure day," said Robert Pavlik, chief market strategist at Boston Private Wealth.
Dow e-minis were up 32 points, or 0.15 percent, at 8:30 a.m. ET (1230 GMT) with 19,617 contracts changing hands.
S&P 500 e-minis were up 3 points, or 0.13 percent, with 104,585 contracts traded.
Nasdaq 100 e-minis were up 9.5 points, or 0.17 percent, on volume of 20,047 contracts.
Of the 181 S&P 500 companies that have released results so far, nearly 77 percent have reported earnings above analysts' expectations. In a typical quarter, about 64 percent of companies have topped earnings estimates, according to Thomson Reuters I/B/E/S.
Among stocks, Under Armour jumped 7.3 percent after the sportswear maker posted a smaller-than-expected quarterly loss.
Bristol-Myers was up 3.4 percent after the drugmaker reported better-than-expected first-quarter earnings and a jump in revenue.
Defense contractor Raytheon rose 1.7 percent following a rise in quarterly revenue.
Microsoft, Amazon.com and Google parent Alphabet are scheduled to report results after the bell. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)