Schedule B will break down by account (i.e. by 1099). If you got $200 in your Fidelity account and $100 in your ETrade account, Schedule B will show it to that level of detail - at least that's what my software has always done. But Schedule B doesn't need to list each and every company. Unless they get reports of issues, the IRS basically assumes that the brokerages know how to categorize them and do so correctly.