Reliance Communications is planning an overseas initial public offering (IPO) for its international communication subsidiary FLAG Telecom, and has short-listed four merchant bankers for the float.Sources said Goldman Sachs, Deutsche Bank, Morgan Stanley and UBS were short-listed for the process, which would see Reliance Communications divest 10-15% equity.FLAG Telecom will be listed on the London Stock Exchange.FLAG is a 100% subsidiary of Reliance Communication, and the proceeds from the IPO will be used to part-finance expansion plans announced last year that include laying 50,000 km fresh undersea cable in regions where there is dearth of international bandwidth.The expansion plan could entail an investment of about $1.5 billion (nearly Rs 7,000 crore).