Wall Street mixed after Yellen's economic warning

The Dow Jones Industrial Average shed 99.64 points (0.62 percent) to end at 15,914.74.

The broad-based S&P 500 lost a scant 0.35 point (0.02 percent) to 1,851.86, while the tech-rich Nasdaq Composite Index gained 14.83 points (0.35 percent) to 4,283.59.

Stocks had initially rallied as Yellen expressed more concern than in her last public comments in December about global economic conditions and financial market volatility.

But those gains evaporated as Yellen also ruled out a rate cut and left open the possibility of further increases later this year.

"A lot of people thought that was not dovish," said Kenny Landgraf of Republic Wealth Advisors. "A lot of people were looking for her to back off."

Analysts said sentiment was also dampened by a fresh slide in US oil prices, after a US government supply report showed stockpiles at a key trading hub rose and US crude production held high despite the recent drop in prices.

Technology shares were mostly higher, with Amazon gaining 1.7 percent, Facebook up 1.5 percent and Priceline jumping 4.2 percent.

Disney led Dow decliners, slumping 3.8 percent as concerns about sliding operating profit at its ESPN sports network more than offset record quarterly net income of $2.9 billion, fueled by strong sales of its blockbuster film "Star Wars".

Other big Dow losers included IBM, which fell 3.1 percent, and Caterpillar, which lost 2.8 percent. Banking stocks JPMorgan Chase and Goldman Sachs declined 1.2 percent and 0.7 percent, respectively.

Time Warner sank 5.0 percent as its fourth-quarter revenue came in at $7.1 billion, well below the $7.5 billion analysts were expecting.

SolarCity plunged 29.3 percent after the solar energy company projected a loss of $2.55 to $2.65 per share in the first quarter, wider than the $2.36 analysts had forecast. (Uu.A026)