| Abbreviation | Definition |
|---|---|
| MANU | Manugistics Group, Inc. |
| MAORY | Mandarin Oriental International |
| MAPAY | Magellan Petroleum |
| MAPS | Mapinfo Corporation |
| MAPX | Mapics, Inc. |
| MARB | Marathon Bancorp |
| MARK | Market America, Inc. |
| MARN | Marion Capital Holdings, Inc. |
| MARPS | Marine Petroleum Trust |
| MARSA | Marsh Supermarkets, Inc. Class A |
| MARSB | Marsh Supermarkets, Inc. Class B |
| MARTW | NationSmart Corporation Warrants |
| MARY | Saint Mary Land & Exploration Company |
| MASB | Massbank Corporation |
| MASH | Massive Interactive, Inc. |
| MASI | Masimo Company |
| MASK | Align Rite International, Inc. |
| MATH | Mathsoft, Inc. |
| MATK | Martek Biosciences Corporation |
| MATR | Matria Healthcare, Inc. |