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Singapore Telecommunications, Southeast Asia’s largest telecommunications operator by revenue, is buying U.S.-based cyber-security firm Trustwave for $810 million, marking its biggest acquisition outside the main telecoms sector.

The deal comes as Singtel is moving away from being a pure-play telecoms company and pursues expansion in areas such as “digital life,” which includes mobile video and digital advertising, and cyber security through partnerships with FireEye and Akamai, among others.

It also comes as the managed security services industry — which refers to the management of an IT system by a third party — is forecast to grow 15 percent annually from 2014 to reach $24 billion in 2018, according to IT consultancy Gartner.

That growth potential has already stoked other acquisitions in the cyber-security business, including BAE Systems’s $232.5 million deal to buy SilverSky and FireEye’s $1 billion takeover of Mandiant, both in 2014.

“Today’s acquisition of Trustwave is a critical step to capturing global opportunities in the cyber-security market,” Singtel CEO Chua Sock Koong told reporters at a briefing.

Before Wednesday’s deal, Singtel spent about S$900 million ($663 million) on acquisitions since 2012, mainly to build its digital life business.

Singtel, which owns stakes in regional operators including India’s Bharti Airtel and Thailand’s Advanced Info Service PCL, will buy a 98 percent equity stake in the company from a group of investors assembled by Trustwave’s chairman and chief executive officer, Robert McCullen. He will hold the remaining 2 percent.

Trustwave will continue to operate as a stand-alone business unit, Singtel said.

Trustwave, which has over three million business subscribers, offers a range of services, including scanning of databases, risk identification and payment compliance. Singtel declined to provide names of specific clients.

Trustwave reported revenue of $216 million in 2014, with the North American market contributing 75 percent.

Last year, Trustwave withdrew its application with the U.S. Securities and Exchange Commission to sell shares in an initial public offering, citing unfavorable market conditions.

Singtel expects the deal, which will be funded through debt and cash, to be completed in three to six months. It forecast the transaction to add to earnings from the third year.

The Asian unit of U.S. investment bank Evercore advised Singtel on the deal.

(Reporting by Aradhana Aravindan; editing by Muralikumar Anantharaman)