MUMBAI: HDFC Securities, one of the leading broking firms in India, on Monday launched an app aimed at taking on the slew of discount brokerages that have captured a large market share in the stock broking space, primarily through low-cost service offerings. Over the last few years, tech-driven discount brokers like Zerodha, Groww, Upstox and 5Paisa have onboarded a large number of traders and investors, mostly at the cost of the large, full-service brokerages.