| Abbreviation | Definition |
|---|---|
| SIDBY | Sime Darby Berhad |
| SIDE | Associated Materials, Inc. |
| SIDE | Associated Materials, Incorporated (de-listed) |
| SIDE | Associated Materials, Incorporated (de-listed) |
| SIDT | S I Diamond Technology, Inc. |
| SIDT | S I Diamond Technology, Incorporated (de-listed) |
| SIDT | S I Diamond Technology, Incorporated (de-listed) |
| SIDY | Science Dynamics Corporation |
| SIEB | Siebert Financial Corporation |
| SIEN | Siena Holdings, Inc. |
| SIFI | SI Financial Group, Incorporated |
| SIFI | Starbase 1 Coffee Company, Ltd. |
| SIFY | Satyam InfoWay, LTD. |
| SIGA | Siga Technologies, Inc. |
| SIGC | Symons International Group, Inc. |
| SIGEP | Southern Indiana Gas & Electric Company |
| SIGGZ | ignet Group PLC |
| SIGGZ | Signet Group PLC |
| SIGI | Selective Insurance Group, Inc. |
| SIGM | Sigma Designs, Inc. |