| Abbreviation | Definition |
|---|---|
| MERC.U | Mercer International Incorporated |
| MET | Metalore Resources Limited |
| MFI | Maple Leaf Foods Inc. |
| MFI | Maple Leaf Foods Incorporated |
| MFL | Minefinders Corporation Ltd. |
| MFL | Minefinders Corporation LTD. (de-listed) |
| MFL | Minefinders Corporation LTD. (de-listed) |
| MFT | Manulife Financial Capital Trust |
| MG | Magna International Inc. |
| MG | Magna International Incorporated |
| MGA | Mega Uranium, LTD. |
| MGN | Magnotta Winery Corporation |
| MGO | Migao Corporation |
| MGT | Mines Management, Inc. |
| MGT | Mines Management, Incorporated (de-listed) |
| MGT | Mines Management, Incorporated (de-listed) |
| MGX | MGM Energy Corp. |
| MGX | MGM Energy Corporation |
| MHR | McGraw-Hill Ryerson Limited |
| MHY | Marret High Yield Strategies Fund |