Tokyo Gas Co., Osaka Gas Co. and a power facility under Nippon Telegraph and Telephone Corp. may jointly enter the electric power retailing business, industry sources said Thursday.

NTT Power and Building Facilities Inc. and the two gas companies are contemplating purchasing surplus electric power generated by various companies with power generation facilities with the intention of selling the energy to NTT group companies as well as other entities, they said.

The three are mulling the adoption one of several possible business strategies, ranging from setting up a joint management venture to reaching a cooperative arrangement without forming such a venture, the sources said.