Few companies embodied the market mania of the past two years quite like Robinhood.

The flashy online brokerage ushered in an investing revolution at the start of the Covid-19 pandemic that, for the first time in decades, made trading cool. Robinhood’s easy-to-use interface hooked millions of Americans on buying and selling stocks, options and cryptocurrencies. A raging bull market helped turn many newbie investors’ trades into wins.