Robinhood Markets shares fell below their initial public offering price in after-hours trading after the retail broker reported softer revenue than expected for the third quarter as trading levels for things like the cryptocurrency dogecoin eased.Shares of Robinhood were down 9.02 per cent at US$36.00 following the release of the results, below the US$38 they were priced at in the Menlo Park, California-based company's July IPO.Robinhood, owner of the trading app that was at the center of January's trading mania for so-called meme stocks, said in August it expects retail investors to take a breather in the third quarter.In its second set of results as a public company, the company posted total revenue of US$365 million for the quarter ended