National Stock Exchange of India Ltd., the operator of the world’s largest derivatives exchange by trading volume, is set to begin formal marketing as early as next week, according to people familiar with the matter, moving ahead with what could be one of the largest-ever initial public offerings in the country.

India’s largest stock exchange plans to hold investor meetings across the US as well as in London, Singapore, Hong Kong, the Middle East and India, according to the people who asked not to be identified because the information is private. NSE is targeting a September IPO and is in discussions with banks on the marketing plan, the people said.

The deliberations are ongoing and details of the offering, including its size, valuation and timing, could still change, the people said. A representative for NSE didn’t respond to requests for comment.

NSE is planning to raise as much as $3 billion, people familiar with the matter have said, part of a wave of mega offerings in India alongside Reliance Industries Ltd.’ digital arm Jio Platforms Ltd. and SBI’s mutual fund unit. The exchange filed its draft prospectus last month for an offering that will consist entirely of secondary share sales. Existing holders plan to sell as many as 148.9 million shares, or about 6% of the company, according to the filing.

NSE is valued at more than 5.25 trillion rupees ($55.1 billion) in the gray market, according to unlisted stock trading platform UnlistedZone.com. At that valuation, selling the entire stake on offer could raise about 306 billion rupees, surpassing the 278.7 billion-rupee listing of Hyundai Motor Co.’s Indian unit in 2024, the country’s largest IPO on record.