$Square, Inc(SQ)$ The free stock trading feature would position Square as a direct competitor for fintech startup Robinhood Markets Inc., which has gained millions of customers by offering no-fee trading, and most recently garnered a valuation of $7.6 billion. Robinhood has since expanded into other offerings such as options trading and margin trading, which would not be offered in Square's initial product, the person sai. Eventually, Sqluare's new service and others like it could pose a challenge to more established online brokers, like E*Trade Financial Corp.