Temasek Holdings Pte. and Life Insurance Corporation of India Ltd. are likely to be key sellers in the potential $2.5 billion initial public offering of India’s top bourse, the National Stock Exchange of India Ltd., according to a person familiar with the matter.State Bank of India Ltd. and SBI Capital Markets Ltd. are also likely to participate as sellers in the long-awaited IPO, which is expected to consist solely of existing shareholders offering between 4 per cent and 4.5 per cent of the company’s equit ...