SoFi Invest accepts orders for whole shares placed after hours, these orders are submitted as Market Orders on Open at the start of the next trading session. These orders go into a special queue when the market opens that executes all of the Market Orders on Open against each other providing there is sufficient liquidity with the security being traded.
Market Orders on Open are not accepted from 9:25 AM and 9:30 AM ET. This order type is not available for fractional shares.