The Alpaca 1099-B forms provide accurate cost-basis reporting information, but there are some limits to that accuracy and compliance with tax reporting. 1099-B wash sales are reported on identical positions (typically an exact symbol match) and only reflect transactions from a single account. However, IRS wash sale rules require taxpayers to calculate wash sales based on “substantially identical” positions (between equities and equity options and equity options at different exercise dates) and across all their individual accounts including IRAs and Roth IRAs.
So, depending upon one’s holdings in other accounts, the calculation of wash sales may be impacted. In any case, the data provided in form 1099-B can, and should, be a starting point.