* Dollar at three-week high; gold slips
* Oil prices up as producers stick to supply cut deal
* Activision top stock on S&P after earnings, buyback
* Indexes up: Dow 0.27 pct, S&P 0.20 pct, Nasdaq 0.18 pct (Updates to open)
By Yashaswini Swamynathan
Feb 10 (Reuters) - U.S. stocks hit record highs shortly after the open on Friday, a day after President Donald Trump said he would release a major tax reform plan in the coming weeks.
Trump's promise of a "phenomenal" tax plan helped reignite a post-election rally, which had stalled in recent weeks on concerns over his protectionist stand and the lack of clarity on his policies.
The biggest theme for investors is that Trump's tax plan will move quickly and he has always maintained that it is going to be very aggressive, said Uriel Cohen, founder of Alpine Global in New York.
"No one wants to miss a large pop when that news does come out."
Jeb Hensarling, the Republican chairman of a key House of Representatives committee, laid out his plan to roll back Wall Street and consumer protection rules, which were put in place after the 2008 financial crisis, according to a staff memo seen by Reuters on Thursday.
Banks, including Morgan Stanley, Bank of America and JPMorgan, were slightly higher. The S&P 500 financial index rose 0.31 percent, giving the broader index its biggest boost.
Goldman Sachs rose 0.78 percent and was the top stock on the Dow.
The dollar index was up 0.3 percent to a three-week high of 101.01. Gold was down 0.3 percent.
Oil prices rose 1.5 percent after news that OPEC members' initial compliance with last year's production cut deal reached a record high.
At 9:38 a.m. ET (1438 GMT) the Dow Jones Industrial Average was up 55.34 points, or 0.27 percent, at 20,227.74.
The S&P 500 was up 4.65 points, or 0.20 percent, at 2,312.52 and the Nasdaq Composite was up 10.07 points, or 0.18 percent, at 5,725.25.
Eight of the 11 major S&P 500 sectors were higher, with energy's 1 percent rise leading the gainers.
Activision Blizzard surged 13.7 percent and gave the biggest boost to the S&P 500. The videogame maker reported better-than-expected quarterly revenue and a $1 billion share buyback program.
Sears Holding jumped 31 percent to $7.27 after the struggling retailer said it would cut debt and pension obligations by at least $1.5 billion this year.
Mead Johnson was up 4.7 percent after Reckitt Benckiser finalised a $16.6 billion deal to buy the infant formula maker.
Skechers USA was up 17.8 percent after its fourth-quarter revenue beat expectations.
Advancing issues outnumbered decliners on the NYSE by 1,770 to 837. On the Nasdaq, 1,396 issues rose and 859 fell.
The S&P 500 index showed 25 new 52-week highs and no new lows, while the Nasdaq recorded 75 new highs and nine new lows. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)