| 1 | BKX | Blaw-Knox Co. | 7/1932-4/1970; eliminated 1/1974 | | NAKINA |
| 2 | BKX | Blaw-Knox Co. | 4/38-4/70; eliminated 1/74 | | NRHS |
| 3 | BKX | BLAW-KNOX CO. | | | PWRC |
| 4 | BKXA | BARKER TRANSPORTATION INC | | | SCAC4 |
| 5 | BKXB | BOOK EXPRESS NETWORK CO | | | SCAC4 |
| 6 | BKXC | BULK EXPRESS INCORPORATED | | | SCAC3 |
| 7 | BKXC | BOYKO TRANSPORTATION LLC | | | SCAC4 |
| 8 | BKXD | BRISK TRANSPORT LTD | | | SCAC4 |
| 9 | BKXE | BAKERY EXPRESS DIVISION | | | SCAC3 |
| 10 | BKXI | BERKELEY EXPRESS INC | | | SCAC3 |
| 11 | BKXL | BALKAN TRANSPORT LLC | | | SCAC4 |
| 12 | BKXN | BULK EXPRESS INC | | | SCAC3 |
| 13 | BKXN | BERKELEY TRANSPORTATION | | | SCAC4 |
| 14 | BKXP | BALKAN EXPRESS INC | | | SCAC4 |
| 15 | BKXQ | BLACK SEA TRANSPORTATION INC | | | SCAC4 |
| 16 | BKXR | BROOKSHIRE EXPRESS SERVICES | | | SCAC3 |
| 17 | BKXS | BLACK RIBBON EXPRESS INC | | | SCAC4 |
| 18 | BKXV | BARRICK TRANSPORT SERVICE INC | | | SCAC4 |
| 19 | BKXY | BROCK EXPRESS INC | | | SCAC4 |
