| Abbreviation | Definition |
|---|---|
| MSSEL | Massachusetts Electric Company |
| MSSEN | Massachusetts Electric Company |
| MSTF | Monarch Staffing, Inc. |
| MSTG | Mustang Alliances, Inc. (formerly Mustang.Com, Inc.) |
| MSTO | Masterbeat Corporation |
| MSTR | Microstrategy, Inc. |
| MSVB | id Southern Savings Bank |
| MSVB | Mid Southern Savings Bank |
| MSYS | Medical Technology Systems, Inc. |
| MTCH | Metron Technology, N. V. |
| MTCI | M G M T Technology, Inc. |
| MTEC | Meridian Medical Technology, Inc. |
| MTEDM | Metropolitan Edison Company |
| MTEK | MetreTek Technologies, Inc. |
| MTEKW | MetreTek Technologies, Inc. Warrants |
| MTEN | Medical Technology Engineering National, INC. |
| MTEN | Medical Technology & Engineering National, INC. |
| MTEX | Mannatech Incorporated |
| MTEY | Material Technologies, Inc. |
| MTGE | American Capital Mortgage Investment Crp |