Data center Equinix will bulk up its presence in Europe through the acquisition of British counterpart TelecityGroup in a cash-and-stock deal valued at around $3.3 billion.

The boards of both companies have agreed to the deal, which will add London-based TelecityGroup's 39 in 11 European countries to Equinix's more than 100 facilities in 15 countries.

TelecityGroup shareholders will hold about a 10 percent stake in the combined company.

Data centers are networks of computer systems that help store and process data.

Equinix Inc., based in Redwood City, California, says its data centers help more than 4,800 companies connect directly to customers.

TelecityGroup says it has ended a merger it agreed to in March with another , Interxion.

Shares of Equinix are slipping in premarket trading.