(ShareCast News) - Shares in payments processor Worldpay slumped on Wednesday as it emerged that private equity firms Advent International and Bain Capital LLP sold a bigger-than-expected stake in the company through their Ship Global 2 & Cy SCA vehicle.Ship Global, which is jointly owned by the two firms, sold 350m shares in the payments processor, which is more than the 300m planned, at 282p per share. They raised aggregate sale proceeds of approximately £987m.Following completion of the placing, Ship Global 2 will hold 214.48m shares in the company, or around 10.7%.Barclays Bank, Goldman Sachs International, Merrill Lynch International and Morgan Stanley & Co. acted as joint bookrunners in connection with the placing, while Lazard & Co was financial adviser to Ship Global 2.At 0840 BST, Worldpay shares were down 3.8% to 283.30p.