National Stock Exchange of India Ltd., the world’s largest derivatives exchange by volume, has downsized its initial public offering, a sign of rising concern over the willingness of investors to buy into the deal at the valuation the firm had been seeking. The company reduced the number of shares offered to 126.44 million from the 148.9 million planned earlier, according to its updated prospectus filed in Mumbai late Thursday.

The offering will consist entirely of existing shares, with about 5.1% of the company’s equity capital on sale, down from about 6% planned earlier, the filing showed. The offering will take orders from investors from Sept. 17 till Sept. 21, with a potential listing on Sept. 24.

NSE’s valuation has come under growing scrutiny as investors worry about slowing growth and tighter regulatory oversight of stock-market activity. Options trading, a key driver of the exchange’s growth, has come under particular pressure as Indian authorities seek to curb speculative derivatives activity. As a result, the company priced the IPO at 1,700 rupees to 1,785 rupees per share, according to a newspaper advertisement. That’s below an earlier marketed range of 2,000 rupees to 2,100 rupees, people familiar with the matter have said.

At the upper end of the price range, selling shareholders could raise as much as 226 billion rupees ($2.4 billion), below the 278.7 billion rupees raised by Hyundai Motor Co.’s Indian unit in 2024 in the country’s largest-ever IPO. It will also value the company at 4.42 trillion rupees, compared with a previously targeted valuation of as much as 5.26 trillion rupees. Even at the reduced size, the deal will give a major boost to the country’s primary market.