| ID | Name | Type |
|---|---|---|
| #13391 | Sinclair Research Ltd [PT] | Z |
| #18976 | Sinclair Society | U |
| #13392 | Sinclair User | Z |
| #13393 | Sinclair User Club | U |
| #13394 | Sinclairland | Z |
| #13395 | Sindicato del Software | Z |
| #13396 | Single | ? |
| #13397 | Sinn | ? |
| #20873 | Sinsoft | P |
| #13398 | Sintax S.A. | Z |
| #13399 | Sintech | ? |
| #13400 | Sinus | - |
| #19242 | Sinus Software | P |
| #13404 | Sir Computers | H |
| #15955 | Sir-Tech | Z |
| #18232 | SirMorris | - |
| #20954 | Sirelion | + |
| #13405 | Sirius Group | Z |
| #13406 | Sirius Logic | ? |
| #13407 | Sirius Software | Z |