[29] Hedge fund manager David Einhorn has accused Elon Musk of "significant fraud",[30] and publicly questioned Tesla's accounting practices, telling Musk in November 2019 that he was "beginning to wonder whether your accounts receivable exist."[31] Tesla has used many "fancy accounting gimmicks" to show positive cash flow and quarterly profits,[32][33] and Bloomberg has questioned whether Tesla's financial reporting violates Generally Accepted Accounting Principles (GAAP) reporting standards.[32]