Take a look at some of the biggest movers in the premarket:

Kansas City Southern (KSU) – Shares of the rail operator surged 18.9% in premarket trading, after Canadian National Railway (CNI) offered $325 per share in cash and stock for the company, topping a prior $275 per share offer from Canadian Pacific (CP). The Canadian National offer also includes $200 per share in cash, compared to $90 for the Canadian Pacific offer. Canadian National tumbled 6.3%, while Canadian Pacific jumped 4%.