1. Please visit FINRA to learn more about Pattern Day Trading Protection
  2. In order to prevent Alpaca Brokerage Account customers from unintentionally being designated as a Pattern Day Trader (PDT), the Alpaca Trading platform checks the PDT rule condition every time an order is submitted from a customer. If the order could potentially result in the account being flagged as a PDT, the order is rejected, and API returns error with HTTP status code 403 (Forbidden).
User Protections - Documentation | Alpaca
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