July 29 (Reuters) - Shares of Robinhood Markets Inc (HOOD.O) fell more than 10% after opening flat in their Nasdaq debut on Thursday, valuing the online brokerage at about $28 billion, a dismal reception to one of the most hotly anticipated listings of the year. Shares fell to $34 in early trading, far lower than the offer price of $38, which was at the lower of end of its initial price offering (IPO) range. The company, arguably the breakout financial technology startup of its generation, priced its IPO on Wednesday and raised $2.1 billion. read more Its long-awaited debut comes months after it was caught in a confrontation between a new generation of retail investors and Wall Street hedge funds. Its decision earlier this year to restrict trading in a few popular stocks following a tenfold rise in deposit requirements at its clearinghouse had enraged the U.S. lawmakers as well as users of its app, a go-to destination for retail investors. Its easy-to-use interface made it a hit among young investors trading from home during coronavirus-induced restrictions and its popularity has soared over the past 18 months Jeff Zell, senior research analyst at IPO Boutique, said there were more skeptics than believers regarding this company at this valuation level. "With that being said, there is a silver lining to this performance, or underperformance, as it sets the "expectations" on the lower end of the scale for Robinhood when it reports its first few quarters," Zell said. "But overall, the company still has a lot to prove." Robinhood"s revenue in the March quarter jumped fourfold, thanks to the trading mania in the so-called meme stocks. But it also came at a cost, putting it at the center of several regulatory probes. The company was forced to raise $3.4 billion in emergency funds after its finances were strained due to the massive jump in retail trading. read more The company was founded in 2013 by Stanford University roommates Vlad Tenev and Baiju Bhatt. The two will hold a majority of the voting power, with Bhatt keeping around 39% of the outstanding stock and Tenev about 26.2%. It had planned to reserve 20% and 35% of its offering for users of its trading platform that allows users to make unlimited commission-free trades in stocks, exchange-traded funds, options and cryptocurrencies. Robinhood Chief Financial Officer Jason Warnick told Reuters he expects the IPO to demonstrate the benefits of allocating a significant chunk of stock to retail investors. read more the company disclosed on Tuesday it has received inquiries from U.S. watchdogs asking if employees traded GameStop Corp (GME.N) and AMC Entertainment (AMC.N) before the online broker publicly announced it was restricting trading in those and other meme stocks on Jan. 28. read more The company is also being probed over whether it complied with personnel registration rules, it said.