NEW YORK (Reuters Breakingviews) - RASCALLY ROBINHOOD. Robinhood Markets, the online brokerage that hosted this year’s rush into so-called meme stocks like GameStop, already paid a fine for hiding information from its users. Now, Reuters reports, it may have neglected to report some of its customer trades to the regulator as required. It will fit right in among Wall Street’s merry men and women. Fines over disclosure to the Financial Industry Regulatory Authority are generally neither big nor rare. Goldman Sachs, Deutsche Bank and Bank of America have all paid a few million dollars or less in cases that usually speak more of procedural glitches than malice. Failure to report some trades hampers FINRA’s ability to monitor markets, but doesn’t leave a trail of direct harm. While a company planning to go public has reason to keep its nose clean, regulatory penalties have in any case become a Wall Street cost of doing business. Citigroup, JPMorgan and Goldman paid huge sums last year for miscellaneous failings. Robinhood is a disruptor, but in the sense that skirmishes with the regulator are a feature of life as a financial swashbuckler, it may prove all too similar to old-school rivals. (By John Foley)