Robinhood, the Bay Area-based fintech that started out with commission-free stock trades and then moved into competitively priced margin lending, started offering commission-free trading in bitcoin and ethereum Thursday in California and four other states.
When the company said last month that it planned to expand into cryptocurrency trading, it saw more than 1 million people join a waiting list for the service. On Thursday, Robinhood said it now has more than 4 million users, making it the fastest-growing…