| 501 | 5126 | Louisville Metabolic and Atherosclerosis Research Center |  | 7775 | 7018 | 2538 | 2510 |
| 502 | 3438 | Louisville VA Medical Center | | 6442 | 6006 | 2538 | 1891 |
| 503 | 2295 | Lovelace Respiratory Research Institute | | 7576 | 3506 | 2411 | 2249 |
| 504 | 732 | Lowell Observatory | | 2221 | 579 | 2024 | 1581 |
| 505 | 2040 | Loyola Law School los Angeles | | 1267 | 605 | 1848 | 3879 |
| 506 | 696 | Loyola University Medical Center | | 2481 | 836 | 2538 | 390 |
| 507 | 1193 | Lunar and Planetary Institute | | 262 | 2158 | 2086 | 1556 |
| 508 | 7179 | Lunar Research Institute | | 7472 | 6481 | 2538 | 3879 |
| 509 | 259 | Lurie Children's Hospital of Chicago (Children's Memorial Hospital) | | 1458 | 566 | 741 | 324 |
| 510 | 6265 | Lynn Health Science Institute | | 7630 | 6257 | 2538 | 3509 |
| 511 | 1645 | Magee-Womens Research Institute | | 6138 | 2922 | 2538 | 1057 |
| 512 | 924 | Maimonides Medical Center Brooklyn New York | | 3327 | 1412 | 1598 | 1490 |
| 513 | 6307 | Maine Center for Cancer Medicine and Blood Disorders | | 7061 | 5101 | 2538 | 3879 |
| 514 | 5500 | Maine Environmental Policy Institute | | 6997 | 3857 | 2538 | 3879 |
| 515 | 1299 | Maine Health | | 1771 | 854 | 2538 | 1960 |
| 516 | 1860 | Maine Medical Center Research Institute | | 4969 | 2981 | 2538 | 1518 |
| 517 | 3981 | Mallinckrodt Institute of Radiology | | 4468 | 4515 | 778 | 3879 |
| 518 | 4534 | Marcus Institute | | 6475 | 2547 | 2538 | 3879 |
| 519 | 237 | Marine Biological Laboratory | | 964 | 307 | 254 | 690 |
| 520 | 2848 | Marine Mammal Center | | 2903 | 640 | 2538 | 3879 |
| 521 | 5418 | Marine Spill Response Corporation | | 6260 | 3840 | 2538 | 3879 |
| 522 | 7330 | Marion VA Medical Center | | 6580 | 6842 | 2538 | 3879 |
| 523 | 1481 | Marlborough Hospital | | 2221 | 1268 | 2538 | 1960 |
| 524 | 536 | Marshfield Clinic | | 1933 | 777 | 1582 | 930 |
| 525 | 4559 | Martin's Point Health Care | | 5103 | 2705 | 2538 | 3879 |
| 526 | 3171 | Mason Research Institute | | 4122 | 2382 | 1484 | 3879 |
| 527 | 3291 | Masonic Medical Research Laboratory | | 7292 | 3841 | 2538 | 2782 |
| 528 | 714 | Massachusetts Eye and Ear Infirmary | | 2895 | 834 | 2538 | 408 |
| 529 | 87 | Massachusetts General Hospital | | 539 | 106 | 2538 | 10 |
| 530 | 5171 | Materials Research Science & Engineering Centers | | 4140 | 3658 | 2538 | 3879 |
| 531 | 542 | Mathematica Policy Research | | 1494 | 637 | 830 | 1454 |
| 532 | 2596 | Mathematical Sciences Research Institute | | 610 | 523 | 2538 | 3879 |
| 533 | 1093 | Mayo Clinic | | 72 | 10 | 2538 | 3879 |
| 534 | 4707 | McCrone Research Institute | | 6103 | 2872 | 2538 | 3879 |
| 535 | 3134 | Mclean Hospital | | 3119 | 871 | 2538 | 3879 |
| 536 | 3909 | Mcleod Health | | 2062 | 1910 | 2538 | 3879 |
| 537 | 1550 | Medical City Hospital | | 1508 | 2209 | 2538 | 1490 |
| 538 | 3958 | MEDNAX Phoenix Perinatal Associates | | 2469 | 1948 | 2538 | 3879 |
| 539 | 840 | Medstar Health Research Institute (MedStar Washington Hospital Center) | | 579 | 752 | 2538 | 930 |
| 540 | 4452 | Memorial Health System Memorial Medical Center Springfield | | 3651 | 2646 | 2538 | 3879 |
| 541 | 2651 | Memorial Hermann Northwest Hospital | | 960 | 544 | 2538 | 3879 |
| 542 | 4707 | Memorial Hospital Jacksonville | | 4953 | 2971 | 2538 | 3879 |
| 543 | 7170 | Memorial Orthopaedic Surgical Group | | 7428 | 6466 | 2538 | 3879 |
| 544 | 7567 | Memphis Medical Center | | 7984 | 6908 | 2538 | 3879 |
| 545 | 3073 | Memphis VA Medical Center | | 6768 | 6347 | 2538 | 1153 |
| 546 | 4494 | Mental Health | | 4916 | 2622 | 2538 | 3879 |
| 547 | 6074 | Mental Illness Research Education and Clinical Centers MIRECC | | 3689 | 5066 | 2538 | 3879 |
| 548 | 2058 | Mercy | | 1120 | 574 | 2006 | 3879 |
| 549 | 185 | Methodist Hospital Houston | | 764 | 562 | 178 | 214 |
| 550 | 5706 | Methodist Sports Medicine Center | | 5188 | 4406 | 2538 | 3879 |
| 551 | 493 | MetroHealth System Cleveland | | 3010 | 872 | 906 | 804 |
| 552 | 6295 | Miami Hand Center | | 6045 | 5223 | 2538 | 3879 |
| 553 | 6512 | Miami Heart Research Institute | | 6983 | 5427 | 2538 | 3879 |
| 554 | 3212 | Miami VA Healthcare System | | 6726 | 6424 | 2538 | 1288 |
| 555 | 2171 | Michael E. DeBakey VA Medical Center | | 6414 | 5978 | 2538 | 446 |
| 556 | 6322 | Michigan Biotechnology Institute | | 7598 | 4990 | 2538 | 3879 |
| 557 | 5325 | Michigan Ear Institute | | 6910 | 3630 | 2538 | 3879 |
| 558 | 5168 | Michigan Headache & Neurological Institute | | 6987 | 3397 | 2538 | 3879 |
| 559 | 5801 | Michigan Molecular Institute | | 6944 | 4357 | 2538 | 3879 |
| 560 | 7524 | Midwest Cardiovascular Research Foundation | | 6944 | 7113 | 2538 | 3879 |
| 561 | 752 | Milton S. Hershey Medical Center Penn State Health | | 2541 | 1397 | 2538 | 222 |
| 562 | 5699 | Minneapolis Heart Institute | | 5940 | 4317 | 2538 | 3879 |
| 563 | 1612 | Minneapolis Heart Institute Foundation | | 4605 | 2944 | 2538 | 1061 |
| 564 | 2620 | Minneapolis Medical Research Foundation | | 7193 | 5215 | 2538 | 1351 |
| 565 | 6419 | Mississippi Sports Medicine and Orthopaedic Center | | 7472 | 5217 | 2538 | 3879 |
| 566 | 659 | Missouri Botanical Garden | | 953 | 233 | 2538 | 1218 |
| 567 | 486 | Mitsubishi Electric Research Laboratories | | 1894 | 886 | 433 | 981 |
| 568 | 6240 | Molecular Sciences Institute | | 8091 | 4379 | 2538 | 3879 |
| 569 | 789 | Monell Chemical Senses Center | | 4651 | 934 | 1208 | 1572 |
| 570 | 123 | Montefiore Medical Center | | 620 | 668 | 217 | 60 |
| 571 | 380 | Monterey Bay Aquarium Research Institute | | 1735 | 396 | 423 | 1113 |
| 572 | 7097 | Morgan Kalman Clinic | | 7562 | 6294 | 2538 | 3879 |
| 573 | 2741 | Moss Landing Marine Laboratories | | 1440 | 4994 | 1350 | 3034 |
| 574 | 1255 | Mote Marine Laboratory | | 2425 | 540 | 1693 | 3140 |
| 575 | 3528 | Mount Auburn Hospital | | 4122 | 1988 | 2538 | 3660 |
| 576 | 1363 | Mount Desert Island Biological Laboratory | | 443 | 1551 | 1978 | 2460 |
| 577 | 36 | Mount Sinai Health System New York City | | 709 | 164 | 194 | 23 |
| 578 | 1467 | Mount Sinai Medical Center | | 2985 | 1450 | 2346 | 2313 |
| 579 | 2984 | Mount Washington Observatory | | 5489 | 662 | 2538 | 3879 |
| 580 | 2963 | Mount Wilson Observatory | | 7193 | 969 | 2538 | 3660 |
| 581 | 7340 | Mountain Quest Institute | | 8011 | 6413 | 2538 | 3879 |
| 582 | 5038 | Mountainside Hospital | | 5623 | 3361 | 2538 | 3879 |
| 583 | 5376 | MPI Research | | 7834 | 3447 | 2538 | 3879 |
| 584 | 3884 | MRI Global (Midwest Research Institute) | | 6748 | 3335 | 1809 | 3879 |
| 585 | 3942 | MSFC Science Research Office (National Space Science & Technology Center) | | 7518 | 1539 | 2538 | 3879 |
| 586 | 5059 | NASA Advanced Supercomputing Division | | 2328 | 3642 | 2538 | 3879 |
| 587 | 1266 | NASA Goddard Institute for Space Studies | | 1301 | 2459 | 2538 | 667 |
| 588 | 3466 | NASA Infrared Telescope Facility | | 2004 | 1299 | 2538 | 3879 |
| 589 | 4514 | NASA Langley Research Center | | 594 | 3038 | 2538 | 3879 |
| 590 | 4361 | NASA Marshall Space Flight Center | | 598 | 2810 | 2538 | 3879 |
| 591 | 6341 | NASA Stennis Space Center | | 5679 | 5303 | 2538 | 3879 |
| 592 | 6801 | Nashville Hip Institute | | 7191 | 5881 | 2538 | 3879 |
| 593 | 7503 | Nashville Neuroscience Group | | 7785 | 6958 | 2538 | 3879 |
| 594 | 1453 | National Academies | | 693 | 176 | 1641 | 3879 |
| 595 | 3200 | National Academy for State Health Policy | | 2614 | 944 | 2538 | 3879 |
| 596 | 1709 | National Academy of Engineering | | 937 | 380 | 2538 | 3316 |
| 597 | 1534 | National Academy of Sciences | | 1834 | 230 | 2538 | 3316 |
| 598 | 3207 | National Academy of Social Insurance | | 3056 | 932 | 2538 | 3879 |
| 599 | 2 | National Aeronautics and Space Administration | | 7 | 3 | 19 | 18 |
| 600 | 1231 | National Audubon Society | | 391 | 71 | 1883 | 3879 |
