The Securities and Exchange Commission should have kept thousands of documents it destroyed from preliminary investigations of financial firms over nearly two decades, according to a government report released Tuesday. But the SEC inspector general found no evidence that any of the investigations were harmed as a result.

Inspector General David Kotz said the agency violated federal rules by giving incomplete information to the National Archives last year about the records. The SEC failed to tell archives officials that the agency’s 20-year policy had been to discard all documents in closed inquiries that didn’t become formal investigations, the report says.