US STOCKS-Wall St lower as investors assess valuations after rally
* All three major indexes on track to end week higher
* Twitter jumps on report company moving closer to sale
* Indexes down: Dow 0.24 pct, S&P 0.21 pct, Nasdaq 0.24 pct (Adds details, changes comment, updates prices)
By Tanya Agrawal
Sept 23 (Reuters) - Wall Street was lower in late morning trading on Friday as investors assess valuations after a three-day rally spurred by optimism that the Federal Reserve will hold off from raising interest rates in the near term.
Some analysts have been questioning valuations as corporate earnings continued to be tepid. The S&P 500 is trading 17.4 times expected earnings, above its 10-year average of 14.7, according to Starmine.
"The market is taking a bit of a breather after a strong week," said Mike Bailey, director of research at FBB Capital Partner, in Bethesda, Maryland.
"Investors are saying markets are already expensive and they've become more expensive this week, so this is a bit of a reversal."
Bailey added that if earnings for S&P companies in 2017 were flat or lower, that would be a major cause for concern. Continuación...