Investors are finally getting a chance to buy into the National Stock Exchange of India, which dominates listings and accounts for over 90% of India's equity market turnover. The NSE has become the world's largest derivatives exchange by volume. This week, it targets a $46bn valuation in its stock market debut.

But after years of delays, a regulatory crackdown and sluggish markets, some wonder where NSE can produce growth. The valuation is down from expectations of more than $50bn, with weak demand prompting a 15% reduction in shares on offer. "A key factor weighing on the valuation has been concern related to the impact on the NSE's lucrative derivatives business of Sebi's recent tightening of retail options trading rules," said Andrei Stetsenko of Farley Capital.

Equity options generated 77% of NSE's transaction revenues last year. Sebi has tightened derivatives rules, cooling speculative trading. Net profit declined 15% to Rs103bn ($1.07bn). "There is excessive control of NSE by Sebi," said Ajay Shah of XKDR Forum.

Still, the NSE owes its ascent to a 1990s government effort to overturn an entrenched market structure. Launched with state backing, it introduced India's first all-electronic exchange and rapidly wrested trading from the Bombay Stock Exchange.