BT has signed a $3bn (£1.7bn) outsourcing contract with Reuters - its biggest ever global outsourcing deal.
As part of the same deal, BT will acquire loss-making financial services extranet provider Radianz from Reuters for £97m.
The contract will see BT become Reuters' supplier of network services for eight and a half years.
BT will provide and manage secure data networks for Reuters products and services worldwide.
BT said the purchase of Radianz is an important step in its strategy of becoming a global provider of networked IT services.
Tom Glocer, Reuters group chief executive, said, "The sale of Radianz sees Reuters exiting the market for the provisioning and management of data networks, which is a major part of our Fast Forward business transformation programme."
Ben Verwaayen, BT chief executive, said, "The acquisition of Radianz is of strategic importance, as the global financial services market offers a huge opportunity to BT."
The capture of Radianz follows BT’s recent acquisitions of Albacom and Infonet.
Reuters and BT had been in negotiations about an outsourcing contract and the transfer of ownership of Radianz since last October.