| M3 Insurance | 135 | $137,072 |
| Macys | 112 | $77,247 |
| Magen J T | 127 | $54,417 |
| Manager | 115 | $222,521 |
| Marathon Oil | 138 | $196,131 |
| Marathon Petroleum | 1,517 | $1,131,309 |
| Marcum | 495 | $393,277 |
| Marcus Millichap | 223 | $7,865,853 |
| Mariner Finance | 200 | $315,059 |
| Marriott | 172 | $126,966 |
| Marriott International | 263 | $216,098 |
| Mars | 109 | $553,990 |
| Marsh | 259 | $550,393 |
| Marsh McLennan | 177 | $217,515 |
| Marsh McLennan Agency | 126 | $234,432 |
| Martin Marietta | 728 | $663,268 |
| Massachusetts General Hospital | 206 | $500,990 |
| Massachusetts Institute of Technology | 115 | $507,218 |
| Massachusetts Mutual Life Insurance | 146 | $194,880 |
| Mass General Brigham | 201 | $322,672 |
| Massmutual | 120 | $273,713 |
| Mastercard | 514 | $933,606 |
| Maxim Healthcare Services | 285 | $82,367 |
| Maximus | 163 | $223,146 |
| Mayer Brown | 179 | $1,091,695 |
| Maynard Nexsen | 283 | $382,626 |
| Mayo Clinic | 705 | $1,053,376 |
| McDermott Will Emery | 141 | $604,165 |
| McDonald S | 300 | $668,991 |
| McDonalds | 106 | $152,869 |
| McGuirewoods | 402 | $1,915,040 |
| McKesson | 158 | $237,384 |
| McKinsey | 364 | $1,411,899 |
| McK McKesson | 214 | $405,623 |
| McPs | 170 | $186,133 |
| MD Anderson Cancer Center | 132 | $183,303 |
| Me | 620 | $857,854 |
| Meba Vacation Trust | 573 | $326,262 |
| Medical College of Wisconsin | 187 | $332,731 |
| Medstar | 122 | $209,583 |
| Medstar Health | 153 | $455,596 |
| Medtronic | 606 | $642,295 |
| Memorial Sloan Kettering Cancer Center | 102 | $274,571 |
| Mercer | 143 | $251,441 |
| Merck | 493 | $1,128,434 |
| Merck Sharp Dohme | 688 | $1,217,257 |
| Mercy | 179 | $247,233 |
| Mercy Health | 139 | $164,564 |
| Merrill Lynch | 376 | $1,007,290 |
| Meta | 1,422 | $3,695,681 |
| Meta Platforms | 212 | $1,014,437 |
| Metlife | 173 | $396,649 |
| Metlife Group | 467 | $481,170 |
| Mgb | 132 | $306,438 |
| Mgh | 155 | $216,566 |
| Miami Dade County | 116 | $119,127 |
| Michael Baker International | 138 | $133,488 |
| Michigan Medicine | 102 | $64,932 |
| Michigan State University | 411 | $935,647 |
| Micron Technology | 140 | $236,853 |
| Microsoft | 5,426 | $12,442,806 |
| Midamerican Energy | 141 | $137,003 |
| Midwest Radiology | 124 | $100,233 |
| Military | 159 | $120,070 |
| Miller Pipeline | 122 | $52,417 |
| Minneapolis Fire Dept | 134 | $34,021 |
| Mit | 566 | $2,220,812 |
| Mitre | 320 | $484,153 |
| Mma | 156 | $149,968 |
| Mmc | 179 | $216,418 |
| Molex | 123 | $139,619 |
| Molina Healthcare | 373 | $927,417 |
| Montana Construction | 131 | $51,030 |
| Montefiore Medical Center | 123 | $226,805 |
| Montgomery County Public Schools | 132 | $99,467 |
| Morgan Lewis | 140 | $794,974 |
| Morgan Lewis Bockius | 154 | $660,657 |
| Morgan Morgan | 116 | $1,289,562 |
| Morgan Stanley | 1,111 | $3,503,488 |
| Morrison Foerster | 184 | $786,266 |
| Moss Adams | 210 | $304,229 |
| Motorola Solutions | 678 | $1,237,089 |
| Mount Sinai | 155 | $237,336 |
| Mount Sinai Hospital | 182 | $196,157 |
| Mr | 148 | $221,386 |
| Ms | 186 | $335,290 |
| Mskcc | 109 | $122,689 |
| Msu | 149 | $305,227 |
| Mta | 124 | $84,274 |
| M T Bank | 186 | $217,534 |
| Mtc | 130 | $118,516 |
| Multicare | 117 | $102,782 |
| Musc | 153 | $160,539 |
| Mutual of Omaha | 208 | $231,591 |
| Myself | 585 | $1,100,079 |