Trading firm Marubeni Corp. and Tokyo Gas Co. announced Thursday that they will form a business alliance to build next-generation broadband, fiber-optic networks using Tokyo Gas’s underground pipes in urban business areas.

The alliance will involve Tokyo Gas obtaining a 20 percent stake in MetroAccess K.K., a wholly owned Marubeni subsidiary capitalized at 400 million yen.

MetroAccess will install optical fiber cables along underground air-conditioning and heating facilities that serve to connect buildings in a certain business area.

The local access lines will be connected to the backbone lines of Global Bandwidth Solutions Inc., a Marubeni group firm that is based in the U.S.

The services, expected to begin next spring, will initially focus on business areas in Tokyo, including the Shinjuku, Ginza and Yaesu districts, company officials said.