If multiple brokers are used, there'll always be a discrepancy between costs on the 1099-B & your SchedD due to wash sales being done across brokers that each individual broker doesn't know about. So, how can the IRS use the costs on the 1099-B as anything except a generalized number as far as audits go? It seems like going strictly by the 1099B's would generate A TON of useless audits for the IRS due to the wash sales across brokers. Does the Sched D data override the 1099-B? It seems like it would.