India, Oct. 6 -- A steep decline in user base and revenues has left India's premier investment tech platforms and discount brokers like Zerodha, Groww, Angel One rattled with the national markets regulator tightening its noose around the high-volume and high-risk F&O trading activities.

India's broking industry has thrived for years on a model built on zero-cost or deeply discounted equity delivery trading, and fees charged from high-turnover, low-cost derivative volumes. Retail investors, encouraged by mobile-first platforms and low entry barriers, flocked to weekly options and expiry-day strategies that set transaction volumes and revenues zooming.

The NSE and BSE together made up more than 80% of the global F&O turnover in April 2025...