US STOCKS-Wall St falls after strong week; Pfizer and Allergan drag
* Pfizer, Allergan drop after biggest-ever healthcare deal
* Energy stocks helped by Saudi move to stabilize prices
* Alcoa up as Elliott takes stake
* Indexes down: Dow 0.17 pct, S&P 0.12 pct, Nasdaq 0.05 pct (Updates to afternoon, adds commentary changes byline)
By Sinead Carew
Nov 23 (Reuters) - U.S. stock indexes closed slightly lower in a quiet trading day on Wall Street after last week's strong gains, while a big healthcare deal failed to impress investors on Monday.
Pfizer's announcement of what is expected to be the biggest-ever healthcare deal pushed its shares down 2.6 percent making it one of the biggest drags on the S&P. Target company Allergan closed 3.4-percent lower after the $160 billion deal announcement.
"Today was a dull day unless you're involved in Pfizer or Allergan. Away from that, it's kind of aimless," said Brian Fenske, head of sales trading at ITG in New York. "Nobody was panicking when the market was going lower. It wasn't really on heavy volume."
The Dow Jones industrial average fell 31.13 points, or 0.17 percent, to 17,792.68, the S&P 500 lost 2.58 points, or 0.12 percent, to 2,086.59 and the Nasdaq Composite dropped 2.44 points, or 0.05 percent, to 5,102.48. Continuación...