US STOCKS-Wall St to open higher on M&A, Citi earnings
* Shire accepts Abbvie takeover offer
* Citigroup up in premarket after earnings, settlement
* Futures up: Dow 77 pts, S&P 8.25 pts, Nasdaq 18.75 pts (Adds Citigroup earnings, updates prices)
By Chuck Mikolajczak
NEW YORK, July 14 (Reuters) - U.S. stocks were poised for a higher open on Monday after the latest flurry of merger activity and earnings from Citigroup, putting the S&P 500 on track to rebound from its worst weekly decline since April.
* London-listed drugmaker Shire Plc succumbed to an increased 31 billion pounds ($53 billion) takeover offer from Abbvie Inc, ending a long-running courtship largely motivated by tax rates. U.S.-listed shares of Shire rose 1.6 percent to $253.08 while Abbvie shed 2.4 percent to $53.62 in premarket trade.
* Generic drugmaker Mylan Inc said it would buy Abbott Laboratories' specialty and branded generics business outside the United States in an all-stock transaction valued at about $5.3 billion. Mylan shares advanced 2.8 percent to $51.60 before the opening bell. Abbott shares rose 1.9 percent to $41.07 in premarket trade.
* Citigroup Inc shares rose 3.9 percent to $48.83 in premarket after it posted second-quarter earnings agreed to pay $7 billion to settle a U.S. government investigation into mortgage-backed securities.