New Delhi, Oct. 15 -- Indian Oil Corp., the country's largest crude oil refiner, plans to acquire a 50% stake in renewable energy firm Fourth Partner Energy Pvt. Ltd (FPEL) through its subsidiary Terra Clean Ltd in a deal with an estimated equity value of about $400 million, according to two people aware of the development.

The deal, if it goes forward, will mark the state-run oil marketing company's first acquisition in the green energy space. It will be a mix of primary and secondary share transactions and will provide a partial exit to Hyderabad-based Fourth Partner Energy's stakeholders-the World Bank's International Finance Corp (IFC), Asian Development Bank (ADB), Germany's Deutsche Investitions- und Entwicklungsgesellschaft (DEG),...