Stocks in the news: Suncor, Tiffany, Citigroup

Suncor Energy (SU) agreed to buy rival Petro-Canada (PCZ) for about $14.86 billion. While the deal comes after a period of missed earnings targets and project delay at Petro-Canada, the all-share offer represents a premium of about 28 percent to PCZ's closing price on Friday. The deal will expand Suncor's oil sand reserves and create Canada's biggest energy group. Shares of Suncor declined over 1 percent in pre-market trade, while PCZ shares soared over 25 percent.

Tiffany $ Co. (TIF) reported Monday that its profit tumbled more than 75 percent in the fourth quarter following a steep drop in sales over the key holiday season.Still, its adjusted results of earnings of 85 cents per share beat analysts' forecasts of 80 cents according to Thomson Reuters, but its 2009 guidance was below expectations. Same-store sales dropped 23 percent during the period, excluding the impact of foreign currency exchange, with a 33 percent drop in the Americas alone. TIF shares are up over 5 percent in pre-market trade.