Holding SPACs Accountable Act of 2021 This bill revises the exclusion from safe harbor protections from liability applicable to forward-looking statements (i.e., statements that predict, project, or use future events as expectations or possibilities) made in connection with certain investments. Specifically, it excludes from the safe harbor a development stage company that has no specific business plan or purpose or has indicated that its business plan is to acquire or merge with an unidentified company, entity, or person (e.g., a special purpose acquisition company).