| ID | Name | Type |
|---|---|---|
| #14124 | Synacroop Software | Z |
| #14125 | Synapse Software Corporation | Z |
| #21137 | Synchron | H |
| #14127 | Syndicate | Z |
| #14128 | Syndrome | ? |
| #14129 | Synergistic Software Inc | Z |
| #14130 | Synergy | Z |
| #14131 | Synsoft Software | Z |
| #17803 | Syntax Computer Services | R |
| #14132 | Syntax Software | Z |
| #19522 | Syntax Software [2] | P |
| #14133 | Syrox | Z |
| #14134 | Syrtis Software | Z |
| #14135 | Sysoft | Z |
| #14136 | Sysop | ? |
| #14137 | System 3 Software Ltd | P |
| #14138 | System 4 | Z |
| #14139 | System 4 de Espana S.A. | Z |
| #22925 | System 6302 | P |
| #14140 | System 7 Electronics | Z |