US STOCKS-S&P 500 ends flat; Fed sees risks but unlikely to reverse course
* Fed not likely to reverse course on rates despite risks
* Disney's 3.8 pct drop weighs on Dow
* Indexes: Dow down 0.6 pct, S&P down 0.02 pct, Nasdaq up 0.4 pct (Updates close with Cisco up, Twitter down after the bell; latest volume)
By Caroline Valetkevitch
Feb 10 (Reuters) - The S&P 500 ended flat on Wednesday, losing gains late in the session as investors digested comments by Federal Reserve Chair Janet Yellen, who kept options open for more rate hikes but also saw risks to the U.S. economy.
The Dow and S&P 500 posted their fourth straight day of losses while the Nasdaq ended its three-day down streak.
Materials and energy shares were Wednesday's biggest losers following further losses in U.S. oil prices.
The market had traded higher for much of the session after Yellen told Congress she does not expect the central bank to reverse the rate hike program it began in December. But Yellen also acknowledged tightening financial conditions and uncertainty about China.
"The market was strong (early in the day) because Janet Yellen confirmed the fact the Fed would go very slow on rate hikes because the economy was showing some signs of sluggishness," said Peter Tuz, president of Chase Investment Counsel in Charlottesville, Virginia. Continuación...