| Abbreviation | Definition |
|---|---|
| MSEL | Merisel, Inc. |
| MSEV | Micron Environmental Systems, Inc. |
| MSEX | Middlesex Water Company |
| MSFT | Microsoft Corporation |
| MSGI | Marketing Services Group, Inc. |
| MSHI | Man Sang Holdings, Inc. |
| MSHS | Minnesota Shares, Inc. |
| MSIA | Mindset Interactive Corporation |
| MSIE | M S I Electronics, Inc. |
| MSIX | Mining Services International Corporation |
| MSLV | Metasolv Software |
| MSO | Martha Stewart Living Omnimedia, Inc. (de-listed; moved to NYSE) |
| MSOF | Multi Soft, Inc. |
| MSOL | Mark Solutions, Inc. |
| MSON | Misonix, Inc. |
| MSPD | Mindspeed Technologies, Inc. |
| MSPD | Mindspeed Technologies, Incorporated (de-listed) |
| MSPT | Millennium Sports Management |
| MSPWO | Mississippi Power Company |
| MSPWP | Mississippi Power Company Preferred |