Guggenheim Partners is planning to spin off a business specializing in repurchase agreements that it started about two years ago, according to people familiar with the plan. The business that started as Guggenheim Liquid Markets, now listed as GLM Securities, might seek external capital while the firm keeps a stake, said the people, who asked not to be identified discussing a private matter. The move would make the unit independent from Guggenheim’s investment bank. Guggenheim has been seeking to find a way to muscle into the market that finances trading in government bonds. By separating the GLM business, Guggenheim expects that it can expand faster, the people said.