US STOCKS-Wall Street falls on broad weakness, Pfizer drags
* Pfizer weighs on Dow, S&P 500
* Mallinckrodt to buy Questcor for $5.6 bln
* MannKind stumbles; FDA extends drug review date
* Indexes down: Dow 0.77 pct, S&P 0.76 pct, Nasdaq 0.97 pct (Updates to midday)
By Chuck Mikolajczak
NEW YORK, April 7 (Reuters) - U.S. stocks fell on Monday, putting the S&P 500 on track for its biggest three-day drop in two months, as investors rotated into defensive names to protect against further declines.
Momentum shares - stocks in fast-growing industries which had seen their stock prices rocket higher in recent weeks - managed to stabilize after their decline helped fuel a sell-off on Friday. But selling pressure migrated to other sectors, with only defensives such as utilities and consumer staples in positive territory among the 10 major S&P sectors.
"We are definitely seeing a little more downside, a continuation from the nasty reversal on Friday," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research in Cincinnati, Ohio.
"The big concern is the overall underlying weakness in so many different stocks. The picture isn't nearly as pretty when you look under the hood and you see various sectors have clearly broken down and now it's starting to pull down on the whole entire stock market." Continuación...