Borders Group Inc, the second-largest U.S. book chain, may file for bankruptcy later this month, a source familiar with matter said. The struggling chain, which operates, 500 stores, will likely close at least 150 stores, according to a separate report by Bloomberg News. Several private equity investors are considering whether to provide a junior loan to the company, according to the report. Bloomberg cited unidentified sources for its story. Borders said on Sunday it would seek to preserve cash by delaying its January payments to vendors and landlords as it tries to complete a debt restructuring. Borders last week secured a $550 million credit facility from GE Capital, a unit of General Electric Co, under several conditions, including that it close stores and arrange financings with other lenders, vendors and landlords. It also warned it might have to file for Chapter 11 bankruptcy if it failed to meet those conditions.