| MManchester | Manchester | CT | 20–99 | ◐ LIKELY ACTIVE |
| MWMann+hummel Water & Fluid Solutions, INC. | Goleta | CA | — | ◐ LIKELY ACTIVE |
| MEManufacturers Equipment CO | Middletown | OH | — | ◐ LIKELY ACTIVE |
| MManufacturing | Elkin | NC | 20–99 | ◐ LIKELY ACTIVE |
| MManufacturing | Willis | TX | 100–499 | ◐ LIKELY ACTIVE |
| MGMaple Grove MN | Maple Grove | MN | 100–499 | ◐ LIKELY ACTIVE |
| MMaplewood-3mus-bldg201 | Maplewood | MN | 1–19 | ◐ LIKELY ACTIVE |
| M3Maplewood-3mus-mn 3m Center | Maplewood | MN | 1–19 | ◐ LIKELY ACTIVE |
| MAMaplewood-3mus-mn Automotive V | Maplewood | MN | 1–19 | ◐ LIKELY ACTIVE |
| MMMaplewood-3mus-mn Med Mkts275 | Maplewood | MN | 1–19 | ◐ LIKELY ACTIVE |
| MQMAR (A Qualfon Company) | Valmeyer | IL | 20–99 | ◐ LIKELY ACTIVE |
| MPMarathon Press | Norfolk | NE | 20–99 | ◐ LIKELY ACTIVE |
| MPMar-Co Packaging | Benton Harbor | MI | 20–99 | ◐ LIKELY ACTIVE |
| MDMarcus Doss Salon LLC | Fayetteville | NC | — | ◐ LIKELY ACTIVE |
| MGMarietta GA Millwork | Marietta | GA | 100–499 | ◐ LIKELY ACTIVE |
| MBMarket Boxx Community Workshop LLC | Milwaukee | WI | — | ◐ LIKELY ACTIVE |
| MHMark Hirai | Los Angeles | CA | — | ◐ LIKELY ACTIVE |
Marking Services Installation, Inc. | Milwaukee | WI | 1–19 | ◐ LIKELY ACTIVE |
| MTMark Thomas Co | Sleepy Eye | MN | 20–99 | ◐ LIKELY ACTIVE |
| MDMarosi Designs LLC, dba BVV | Naperville | IL | 20–99 | ◐ LIKELY ACTIVE |
| MWMartinsburg Wv - Annex | Martinsburg | WV | 20–99 | ◐ LIKELY ACTIVE |
| MWMartinsburg Wv - Caperton Blvd | Martinsburg | WV | 100–499 | ◐ LIKELY ACTIVE |
| MFMartin's Fiberglass INC | Houston | TX | — | ◐ LIKELY ACTIVE |
| MRMasonry Reinforcing Corp of America dba Wirebond | Charlotte | NC | 100–499 | ◐ LIKELY ACTIVE |
| MHMaterial Handling Division | Nashville | TN | 100–499 | ◐ LIKELY ACTIVE |
| MLMatrix Label Systems, Inc. | Plainfield | IN | 20–99 | ◐ LIKELY ACTIVE |
| MLMaxim Label & Packaging High Point, INC. | High Point | NC | 20–99 | ◐ LIKELY ACTIVE |
| MLMaxVision, LLC | Marietta | GA | 1–19 | ◐ LIKELY ACTIVE |
| MCMayfield Consumer Products | Hickory | KY | 100–499 | ◐ LIKELY ACTIVE |
| MNMayport NAS | Jacksonville | FL | 1–19 | ◐ LIKELY ACTIVE |
| MNMaze Nails | Peru | IL | 20–99 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Baltimore) | Baltimore | MD | 20–99 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Baton Rouge, LA) | Gonzales | LA | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Carter Rd, OH) | Cleveland | OH | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Charlotte, NC) | Charlotte | NC | 20–99 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Chattanooga, TN) | Chattanooga | TN | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Cincinnati, OH) | Cincinnati | OH | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Cleveland, OH) | Cleveland | OH | 100–499 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Dallas, TX) | Dallas | TX | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Denver) | Denver | CO | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Distribution Center) | Memphis | TN | 20–99 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Dolomite) | Dolomite | AL | 20–99 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (East Chicago, IN) | East Chicago | IN | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Granite City) | Granite City | IL | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Lafayette) | Lafayette | LA | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Longview) | Longview | TX | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Memphis) | Memphis | TN | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Oklahoma City) | Oklahoma City | OK | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (Pittsburgh, PA) | Cranberry Twp | PA | 1–19 | ◐ LIKELY ACTIVE |
| MLMazzella Lifting Technologies (San Antonio) | San Antonio | TX | 1–19 | ◐ LIKELY ACTIVE |