Mumbai, Sept. 12 -- Some of the world's top asset managers and sovereign wealth funds are lining up to pick up a slice of India's largest stock exchange in its upcoming initial public offering (IPO), according to people familiar with the matter. Fidelity International Ltd, Prudential Plc and Singapore's GIC Pte, are likely to participate in the anchor book of the National Stock Exchange of India Ltd's (NSE) smaller-than-planned IPO, the people said, asking not to be identified because the information is private. Abu Dhabi-based Lunate Capital Ltd, Norway's Norges Bank Investment Management, Eastspring Investments-the Asian asset management unit of Prudential-and US's BlackRock Inc are also likely eyeing the portion reserved for anchor inves...