RPG Group is planning to invest Rs 2,500 crore for retail expansion across the country over the next four years."The company plans to invest around Rs 1,000 crore in the first phase of expansion of its retail venture Spencer's. The first phase will end in 2009. For the second phase, we have lined up an additional investment of Rs 1,500 crore for further expansion till 2011," Sanjiv Goenka, vice chairman, RPG Enterprises, said.He added that the company would raise funds for the planned expansion through a mix of resources, which includes private placements and internal accruals.Goenka did not rule out the possibility of a public issue and a fresh listing of its retail venture.