The National Stock Exchange is preparing the groundwork for roping in the next set of investors within a year.

The move follows a 26 per cent stake sale by the existing investors to overseas investors in two tranches early this year.

According to market information, the valuation this time is likely to exceed $3 billion compared with a valuation of around $2.5 billion in the first tranche, when the New York Stock Exchange and three others picked up 20 per cent (5 per cent each). According to market information, the valuation this time around is likely to exceed the $3.2 billion mark.

Later in March, Morgan Stanely, Citigroup and private equity investor Actis bought another 6 per cent stake in NSE, taking the combined FDI stake in NSE to 26 per cent, the limit prescribed under regulations.

Foreign investors can buy 49 per cent stake in Indian stock exchanges (26 per cent through the foreign direct investment route and another 23 per cent through the foreign institutional investor (FII) route). No single investor is allowed to own more than 5 per cent in an exchange.

Sources said the proposed next tranche of the stake sale would see existing domestic shareholders, including IDBI, Life Insurance Corporation (LC) and State Bank of India (SBI) reducing their stakes to 5 per cent, as required by the demutualisation guidelines.

After the first two tranches, the six major shareholders such as SBI, LIC and IDBI will have to sell a total of 23.56 per cent in NSE, if these investors were to bring down their individual stake to 5 per cent each, according to sources.

Recently, Financial Technologies (the promoter of commodities bourse MCX) bought 1 per cent stake in NSE for Rs 125 crore (Rs 1.25 billion), valuing the exchange at $3.2 billion.

Reports also indicated that Kotak Mahindra Bank was also picking up stake in the exchange. Since the FDI limit had been touched, the new set of investors would also be domestic investors, sources said.

FIIs could come in only at the IPO stage, they said.