Amazon.com IncSpaceX stock fell on Wednesday for the first time since the company went public, breaking a three-session winning streak. The stock ended down nearly 5%, trimming a debut rally that had at one point reached roughly 58% above the IPO price. The slide arrived just a day after SpaceX edged past Amazon to become the fifth-most-valuable stock, having briefly also climbed above Microsoft during Tuesday's trading. Retail investors have bought more SpaceX stock than any other name on every trading day since the offering, with net buying of $144.6 million on Tuesday alone and a total of $369.8 million over the last three sessions, according to Vanda Research. Only about 4.2% of total shares are free to trade, amplifying moves, while looming insider selling and cooling options sentiment—with puts making up 44% of flow—added pressure.