Global Payments has agreed to buy rival Worldpay from FIS and private equity firm GTCR for $24.25 billion in a three-way deal, sharpening its focus on merchant services in its race for big-business clients in a crowded payments market. As part of the deal announced on Thursday, Global Payments will sell its issuer solutions unit, which offers card processing and account services, to FIS for $13.5 billion. The agreements will be transformative for two of the world's largest processors of digital