Idea Cellular is planning an initial public offering (IPO) to raise Rs 14-18 billion in January/February 2007. The Birlas are open to divesting about 25 per cent of their stock and may also look at placing 8-10 per cent with a private investor before the IPO. The operator had initially intended to place 33 per cent with private investors such as the Blackstone Group and Providence Equity Partners, but was unable to come to an agreement regarding the valuation.