An investor in First Data Corp. on Wednesday filed a shareholder class action in Delaware Chancery Court claiming that the credit card service firm’s $22 billion sale to Fiserv Inc. earlier this year had shortchanged investors.

According to the complaint, the all-stock deal was riddled with conflicts and designed to protect KKR & Co. Inc., First Data’s controlling shareholder, which took the company private in 2007 in one of the largest leveraged buyouts ever.