India, April 21 -- Billionbrains Garage Ventures Ltd reported fourth-quarter profit that was above estimates, as investors seek growth to justify a 100% jump in the stock since its initial public offering (IPO)-a surge that has made it the world's most expensive brokerage. Net income more than doubled to Rs.686 crore ($74 million) in the three months ended March from a year ago, versus analysts' estimate of Rs.660 crore However, the company's shares fell 1.1% after the earnings release on Monday, erasing gains of as much as 3.6%. "Groww has reported strong results driven by uptick in derivatives broking revenue amid volatile markets," Sunny Agrawal, head of fundamental research at SBI Securities, said. "The stock has run-up from recent lows and trades at richer valuations-the negative reaction post results is likely profit booking." A near-100% gain since its November IPO price had investors looking closely at earnings strength, and made it the most expensive retail broking stock in the world. They were also closely tracking the company's efforts to diversify from discount broking into wealth management and consumer lending. The broker's focus on new businesses including wealth management and mutual funds with sustained growth in broking can sustain premium valuations, Agrawal said. Groww's market share climbed to 28.3% in the fiscal year ended March 31 from 26.26% a year earlier, bucking a slowdown in retail trading on the National Stock Exchange, data from the nation's biggest bourse show. The expansion had driven Groww's valuation to 43 times its one-year forward earnings last week-well above Robinhood Markets Inc., Interactive Brokers and local peer Angel One Ltd-to make it the priciest broking stock among peers with market value of over $2 billion, per data compiled by Bloomberg. "Groww is well positioned to outpace industry growth," BofA Securities analyst Madhur Sharma wrote in a report before the earnings, pointing to its strong focus on new-to-investing customers and increasing product adoption among existing users....