US STOCKS-Wall St to open lower as momentum stocks stay weak
* Mallinckrodt to buy Questcor for $5.6 bln
* MannKind stumbles; FDA extends review date for insulin treatment
* Futures off: Dow 54 pts, S&P 7.5 pts, Nasdaq 29.25 pts (Updates prices)
By Chuck Mikolajczak
NEW YORK, April 7 (Reuters) - U.S. stocks were set for a lower open on Monday, putting the S&P 500 on track for its third straight decline, as weakness in momentum names that sent the Nasdaq and benchmark S&P index to their worst drop since February in the prior session appeared poised to continue.
* Declines in momentum names such as Netflix Inc and TripAdvisor Inc overshadowed the relatively strong March payrolls report on Friday, leaving investors anxious about how much further they may fall. Facebook Inc lost 1.3 percent to $56 in premarket trade.
* Earnings season gets under way this week, with earnings expected from financials JPMorgan Chase & Co and Wells Fargo & Co, as well as retailer Bed, Bath & Beyond .
* S&P 500 companies' first-quarter earnings are projected to have increased just 1.2 percent from a year ago, Thomson Reuters data showed. The forecast is down sharply from the start of the year, when growth was estimated at 6.5 percent.
* A lackluster first-quarter earnings season impacted by harsh winter weather could spark a pullback, according to some analysts, with investors looking for optimism for the second quarter. Continuación...