* Financials post back-to-back weekly losses
* Adobe, Tiffany up after earnings
* Dow down 0.1 pct, S&P 500 down 0.13 pct, Nasdaq flat (Updates to market close, changes comment, byline)
By Rodrigo Campos
NEW YORK, March 17 (Reuters) - U.S. stocks dipped on Friday as bank shares fell alongside Treasury yields while Adobe helped buoy the S&P tech sector and the Nasdaq Composite.
Amgen was the largest drag on both the S&P 500 and Nasdaq, down 6.4 percent at $168.61, after the extent of a cholesterol drug's benefits in a highly anticipated study disappointed investors, even if it cut the risk of heart attacks and strokes by over 20 percent in patients with heart disease.
The S&P tech index was supported by Adobe's surge to a record high of $130.30 after the Photoshop software maker reported strong earnings. The stock ended up 3.8 percent at $127.01.
Indexes were little changed for a second day even if the Nasdaq Composite touched a record intraday high. Analysts say investors are expecting a catalyst to thrust stocks higher after bets on President Trump's promises of tax cuts and a fiscal stimulus drove Wall Street to all-time highs on a weeks-long rally.
"Investors are moving from sector to sector dependent on where the U.S. dollar is, comments from the White House on the health care act, and earnings," said Quincy Krosby, market strategist at Prudential Financial in Newark, New Jersey.
"The 10-year (benchmark U.S. Treasury note yield) dipped below 2.5 percent and financials pull back while utilities get bid. This churn is a way for the market to consolidate."
Analysts increasingly worry that the Trump administration is spending too much of its political capital in an effort to pass a Republican-proposed healthcare bill, which may leave it wanting for support when it tries to reform the tax code.
Bets on the passing of a tax reform are one of the pillars of the equities rally since the November presidential election.
"This is a market waiting for its next catalyst and I think it wants to hear it from the White House," Krosby said. "That's very important for a market that embraced the pro growth agenda of the Trump administration.
The Dow Jones Industrial Average fell 19.93 points, or 0.1 percent, to end at 20,914.62, the S&P 500 lost 3.13 points, or 0.13 percent, to 2,378.25 and the Nasdaq Composite added 0.24 point, or 0 percent, to 5,901.00.
For the week the S&P rose 0.2 percent, the Dow gained less than 0.1 percent and the Nasdaq added 0.7 percent.
The S&P 500's financial sector posted its first back-to-back weekly decline since September.
Tiffany touched a 19-month high of $94 after higher-than-expected quarterly results. Shares of the high-end jeweler closed up 2.7 percent at $92.42.
About 9.68 billion shares changed hands in U.S. exchanges, compared with the 7.1 billion daily average over the last 20 sessions.
Advancing issues outnumbered declining ones on the NYSE by a 1.51-to-1 ratio; on Nasdaq, a 1.43-to-1 ratio favored advancers.
The S&P 500 posted 64 new 52-week highs and three new lows; the Nasdaq Composite recorded 175 new highs and 58 new lows.
(Reporting by Rodrigo Campos; Editing by James Dalgleish)