| Serene Health Services LLC | Administrative and Support and Waste Management | $1,625,000 | $1,634,038 | 210 | $45.5M |  Research |
| The Platt Brothers and Company | Manufacturing | $1,600,000 | $1,611,353 | 92 | $25.7M | Research |
| The Platt Brothers & Co | Manufacturing | $1,600,000 | $1,610,214 | 87 | $24.3M | Research |
| Portmeirion Group USA Inc. | Wholesale Trade | $1,577,300 | $672,987 | 122 | $37.4M | Research |
| The Eye Care Group P.c. | Health Care and Social Assistance | $1,407,835 | $1,423,908 | 150 | $47.1M | Research |
| Mercury Fuel Service, Incorporated | Retail Trade | $1,245,500 | $1,257,000 | 170 | $56.9M | Research |
| American Republican, Incorporated | Information | $1,228,700 | $1,239,775 | 130 | $21.8M | Research |
| Therap Services INC | Information | $1,039,355 | $1,051,315 | 81 | $13.6M | Research |
| Michaels INC | Retail Trade | $1,026,281 | $1,032,610 | 96 | $26.5M | Research |
| Cheshire House LLC | Health Care and Social Assistance | $1,013,500 | $1,027,300 | 190 | $32.3M | Research |
| Neurosurgery Orthopaedics & Spine Specialists, P.c. | Health Care and Social Assistance | $1,000,307 | $1,008,584 | 86 | $27.0M | Research |
| Albert Bros., Inc. | Wholesale Trade | $997,500 | $1,008,705 | 64 | $19.6M | Research |
| Gem Manufacturing Co., Inc. | Manufacturing | $986,800 | $994,181 | 101 | $24.7M | Research |
| Albert Brothers INC | Wholesale Trade | $882,880 | $887,863 | 44 | $13.5M | Research |
| Neurosurgery Othropaedics & Spine Specialties PC | Health Care and Social Assistance | $845,443 | $853,923 | 68 | $21.3M | Research |
| Neoperl INC | Manufacturing | $801,983 | $813,145 | 61 | $14.9M | Research |
| Opticare PC | Health Care and Social Assistance | $787,800 | $794,168 | 59 | $18.5M | Research |
| Holy Cross High School of Waterbury, Incorporated | Educational Services | $774,600 | $779,078 | 88 | N/A | Research |
| Diagnostic Radiology Associates LLC | Health Care and Social Assistance | $766,904 | $770,644 | 46 | $14.4M | Research |
| Holy Cross High School of Waterbury INC | Educational Services | $762,885 | $765,623 | 80 | N/A | Research |
| The Waterbury Young Men's Christian Association | Other Services (except Public Administration) | $713,917 | $719,550 | 126 | N/A | Research |
| The Waterbury Young Men's Christian | Other Services (except Public Administration) | $713,917 | $720,274 | 189 | N/A | Research |
| Chase Collegiate Education, LLC | Educational Services | $701,659 | $708,637 | 57 | $6.8M | Research |
| There for You Homecare Services LLC | Health Care and Social Assistance | $697,980 | $707,599 | 55 | $9.4M | Research |
| C. & H. Electric, Inc. | Construction | $686,303 | $688,728 | 65 | $22.1M | Research |