| Sension GmbH | |
| SensoPart Industriesensorik GmbH | Baden-Württemberg |
| Sensorberg GmbH | |
| Senstar GmbH | Baden-Württemberg |
| SENTECH Instruments GmbH | |
| Sentronic GmbH | Saxony |
| Sentronics Metrology GmbH | |
| Seo Agentur Ara8 GmbH | Bavaria |
| SEO Agentur Digitaleffects GmbH | |
| SEO Bavaria GmbH | |
| SEO Doktor | |
| SEO GmbH | Berlin |
| SEO und SEA | Saxony |
| SEO-Analyse.com | Baden-Württemberg |
| SEO-HD Suchmaschinenoptimierung | |
| SEO-Küche Internet Marketing GmbH & Co. KG | Bavaria |
| SEO.Organic | Hamburg |
| Seobility GmbH | Bavaria |
| Seobunny | North Rhine-Westphalia |
| Seocomplete GmbH | North Rhine-Westphalia |
| SeoGoal | |
| Seoline GmbH | North Rhine-Westphalia |
| Seonative | |
| seoPOINT | Berlin |
| SEOprofiler | Rhineland-Palatinate |
| Seosmart GmbH | Berlin |
| seosupport GmbH | Berlin |
| Seotrust GmbH & Co. KG | Hesse |
| seo|maxx Michael Pauls | Berlin |
| SEPAexpress | |
| Sepia GmbH & Co. KG | North Rhine-Westphalia |
| sepp.med Software GmbH | Bavaria |
| Sequantrix GmbH | |
| Sequantrix GmbH | |
| Sequiserve GmbH i.L. | |
| Sercos International e.V. | Baden-Württemberg |
| Sereact GmbH | |
| Serenitystudio | North Rhine-Westphalia |
| Sergei Pleis Softwareentwicklung | Hesse |
| SerialInternet | Hamburg |
| Serious Business GmbH | Bavaria |
| Serious Games Solutions | |
| Serious Play | |
| SerNet Service Network GmbH | Lower Saxony |
| SeRo Systems GmbH | |
| Sertronics AG | Hamburg |
| Sertronics GmbH | Hamburg |
| Serum Life Science Europe GmbH | |
| ServeNet GmbH | |
| ServerMind | Bavaria |