* Republicans unveil new healthcare bill
* Banks due to kick off earnings season Friday
* Indexes up: Dow 0.1 pct, S&P 0.2 pct, Nasdaq 0.2 pct (Updates to close)
By Kimberly Chin
NEW YORK, July 13 (Reuters) - Wall Street posted slight gains on Thursday and the Dow hit another record high close, with financials rising ahead of profit reports due Friday from several big U.S. banks.
The financial index was the best performer among the 11 major S&P sectors, ending up 0.61 percent.
Quarterly earnings kick off on Friday with three of the biggest U.S. banks including JPMorgan Chase, Wells Fargo and Citigroup reporting results.
"People are a trying to buy in ahead of tomorrow," said Brad McMillan, chief investment officer for Commonwealth Financial in Waltham, Massachusetts.
Analysts estimate second-quarter earnings for S&P 500 companies rose 7.8 percent from a year ago, with financials projected to have had the third-best profit growth among sectors, according to Thomson Reuters I/B/E/S.
Over the last seven trading days, investors have more than doubled the amount of cash invested in a key financial sector fund, betting that second-quarter bank earnings will be strong.
The Dow Jones Industrial Average rose 20.95 points, or 0.1 percent, to 21,553.09, the S&P 500 gained 4.61 points, or 0.19 percent, to 2,447.86 and the Nasdaq Composite added 13.27 points, or 0.21 percent, to 6,274.44.
Federal Reserve Chair Janet Yellen told a Senate panel on Thursday that it would be "quite challenging" for U.S. growth to reach a 3-percent target set by President Donald Trump.
The S&P 500 healthcare index was up 0.09 percent, barely moving on news of U.S. Senate Majority Leader Mitch McConnell's unveiling of a revised healthcare bill.
"Even if this bill is passed, there will be multiple iterations of healthcare legislation to come," said Jamie Cox, managing partner at Harris Financial Group in Richmond, Virginia.
"This is not a watershed moment like the Affordable Care Act, where it altered the healthcare industry," he said.
Hospital and insurer groups have been vocal against proposed Medicaid cuts which could result in lower revenues for hospitals like Community Health Systems Inc and Medicaid insurance specialists like Molina Healthcare and Centene Corp .
Investors are eager to move past the healthcare bill and onto comprehensive tax reform, though Congress's ability to address it soon are in doubt, Cox said. Target Corp rose 4.8 percent after an upbeat second-quarter forecast. The news boosted other retailers, with Wal-Mart up 1.5 percent and Costco edging up 1.2 percent.
Delta Air Lines Inc on Thursday reported a 21 percent drop in second-quarter profit because of sharply higher operating costs, despite higher passenger unit revenue, sending its shares down about 1.8 percent.
About 5.8 billion shares changed hands on U.S. exchanges, below the 6.8 billion daily average for the past 20 trading days, according to Thomson Reuters data.
Advancing issues outnumbered declining ones on the NYSE by a 1.11-to-1 ratio; on Nasdaq, a 1.01-to-1 ratio favored advancers.
Additional reporting by Caroline Valetkevitch in New York and by Ankur Banerjee and Tanya Agrawal in Bengaluru; Editing by Arun Koyyur and Nick Zieminski