* Dow down 0.73%, S&P 500 down 0.88%, Nasdaq down 1.02%
* Weak demand for $21 bln sale of 30-year Treasury bonds
* PepsiCo gains on quarterly profit, sales beat
* Disney beats earnings estimates but ends down
* Salesforce rises on reports Third Point owns stake
Feb 9 (Reuters) - U.S. stock indexes ended lower on Thursday, erasing earlier gains as Treasury yields rose after an auction of 30-year bonds went poorly and overshadowed strong earnings from corporate giants like Disney and PepsiCo.
"The stock market started today's session with a distinct bullish bias, but then Treasury yields moved up and that took some of the steam out of the positive market today," said Jason Ware, chief investment officer at Albion Financial Group in Salt Lake City, Utah. He said investors were also still digesting recent comments from Fed officials.
Yields on the U.S. 30-year note rose after the Treasury Department saw weak demand for a $21 billion sale, the final sale of $96 billion in coupon-bearing supply this week. In a note to clients, Jefferies said "the buyside bid failed to come together."
The Dow Jones Industrial Average fell 249.13 points on Thursday, or 0.73%, to 33,699.88, the S&P 500 lost 36.36 points, or 0.88%, to 4,081.5 and the Nasdaq Composite dropped 120.94 points, or 1.02%, to 11,789.58.
Volume on U.S. exchanges was 11.49 billion shares, compared with the 11.93 billion average for the full session over the last 20 trading days.
"With Treasury yields higher, it becomes a legitimate alternative to equities," said Michael Rosen, chief investment officer at Angeles Investments.
Wall Street's three main indexes opened higher on Thursday after data showed initial claims for state unemployment benefits rose 13,000 to a seasonally adjusted 196,000 last week, above a forecast of 190,000 claims.
The data tentatively eased concerns about the Federal Reserve's rate-hike path after a strong January employment report rattled markets last week.
Weighing on the S&P 500 and Nasdaq indexes, Alphabet Inc extended losses from the previous session to fall 4.7%. All 11 S&P 500 sectors posted losses.
The Google parent's new chatbot shared inaccurate information on Wednesday, feeding worries that it is losing ground to rival Microsoft Corp.
Disney Co beat earnings estimates and announced job cuts, encouraging activist investor Nelson Peltz to terminate his quest for a board seat. Still, it ended down 1.27%.
Salesforce Inc rose 2.38% on reports that hedge fund Third Point LLC owns a stake in the company.
Stocks have enjoyed an upbeat start to the year on hopes that the Fed will abandon its hawkish rhetoric and pilot the economy to a soft landing.
Traders are betting that the Fed will raise its benchmark rate to a peak of 5.1% in July, largely in line with the forecasts of Fed officials.
PepsiCo Inc rose 0.95% as the snack and beverage maker reported better-than-expected results, while drugmaker AbbVie Inc gained 2.82% after beating fourth-quarter profit expectations.
Tapestry Inc soared 3.47% on a strong annual profit forecast.
More than half of the S&P 500 companies have reported quarterly earnings so far, and 69% of them have beaten estimates, according to Refinitiv data.
Cardiovascular Systems Inc soared 48.38% after Abbott Laboratories said it would buy the medical device maker for $837.6 million. Abbott fell 1.93%.
Declining issues outnumbered advancing ones on the NYSE by a 2.74-to-1 ratio; on Nasdaq, a 2.37-to-1 ratio favored decliners.
The S&P 500 posted 15 new 52-week highs and one new low; the Nasdaq Composite recorded 75 new highs and 57 new lows.