Kansas City Southern has rejected a $20 billion takeover offer from an investor group, the Wall Street Journal reported Wednesday. Global Infrastructure Partners and the infrastructure arm of private-equity firm Blackstone Group Inc. offered KCS $208 a share, the paper reported, citing people familiar with the situation. KCS rejected the bid, arguing it undervalued the company. KCS turned away an earlier bid that was below $200 a share. The two sides are not in discussions, the paper reported.