US STOCKS-Wall St flat ahead of Yellen speech
* Yellen to speak in New York at 12:20 p.m. ET
* Chipotle down after rating downgrade
* Dow down 0.25 pct, S&P down 0.19 pct, Nasdaq up 0.11 pct (Adds details, changes comment, updates prices)
By Abhiram Nandakumar
March 29 (Reuters) - A decline in oil prices kept the S&P 500 and the Dow slightly in the red on Tuesday, ahead of Federal Reserve Chair Janet Yellen's speech on monetary policy.
Yellen, who is due to speak before the Economic Club of New York at 12:20 p.m. ET (1620 GMT), will make her first remarks since the Fed's meeting in March.
The central bank has said it will depend on economic data before it makes a decision on rates, but several policymakers have voiced support for more than one increase this year.
Investors will keep a close eye on Yellen's speech as they look for fresh drivers that could push stocks higher.
"The market is essentially expecting her comments to remain somewhat dovish, just like at her last press conference (in March)," said Tim Dreiling, regional investment director at the Private Client Reserve at U.S. Bank in Kansas City. Continuación...