| AMERICAN INDIAN MANAGEMENT SERVICES, L.L.C. | C175809 | 2007-10-24 | Dissolved | MISSOULA |
| American Indian Movement Montana | D1436447 | 2024-04-29 | Active | — |
| AMERICAN INDIAN OFFICE PRODUCTS, INC. | D095995 | 1998-09-03 | Dissolved | — |
| AMERICAN INDIAN OIL COMPANY | F001869 | 1924-09-11 | Expired | — |
| AMERICAN INDIAN PARTNERSHIP | D255805 | 2014-12-09 | Dissolved | — |
| AMERICAN INDIAN PLASTICS, INC. | D070045 | 1990-08-20 | Dissolved | — |
| AMERICAN INDIAN RESEARCH AND DEVELOPMENT CORPORATION | D042704 | 1976-03-03 | Dissolved | — |
| American Indian Solutions, LLC | C1176601 | 2020-09-30 | Dissolved | — |
| AMERICAN INDIAN TELECOMMUNICATIONS, INC. | D055416 | 1982-09-23 | Dissolved | — |
| AMERICAN INDIAN YOUTH RUNNING STRONG, INC. | F061904 | 2011-02-28 | Active | — |
| American Industrial Coatings Inc. | F1437976 | 2024-04-14 | Active | — |
| AMERICAN INDUSTRIAL CONSTRUCTION, INC. | F010013 | 1975-08-27 | Revoked | — |
| AMERICAN INDUSTRIAL HYGIENE LLC | C234112 | 2013-02-08 | Dissolved | SHEPHERD |
| American Industrial Medicine, PLLC | C1478119 | 2024-10-09 | Active | — |
| AMERICAN INDUSTRIAL REFRIGERATION, INC. | F026627 | 1995-05-18 | Withdrawn | EXCELSIOR |
| AMERICAN INDUSTRIAL SYSTEMS, INC. | D274631 | 2016-04-04 | Dissolved | — |
| AMERICAN INDUSTRIES OF MONTANA LLC | C259055 | 2015-03-09 | Active | MISSOULA |
| AMERICAN INDUSTRIES, INC. | F012709 | 1980-09-08 | Withdrawn | — |
| AMERICAN INDUSTRIES, INC. | D228593 | 2012-08-09 | Active | — |
| AMERICAN INFRASTRUCTURE CORPORATION | D197191 | 2009-08-21 | Dissolved | — |
| American Infrastructure LLC | C1511969 | 2025-02-27 | Active | — |
| American Infrastructure Partners, LLC | C1500564 | 2025-01-17 | Active | — |
| AMERICAN INMATE PHONE SYSTEMS, INC. | F022754 | 1992-01-06 | Revoked | CHICAGO |
| AMERICAN INMATE PHONE SYSTEMS, INC. | F021653 | 1990-08-27 | Revoked | CHICAGO |
| American Innovation Project | F1608156 | 2026-02-06 | Active | — |
| AMERICAN INNOVATIVE MARKETING, INC. | D244225 | 2014-01-06 | Dissolved | — |
| AMERICAN INNOVATIVE MINERALS, LLC | E061999 | 2011-03-16 | Withdrawn | HELENA |
| AMERICAN INNS | D037342 | 1972-05-12 | Dissolved | — |
| American Inspection Services, LLC | C1098312 | 2018-10-26 | Dissolved | — |
| American Installation, llc | C1627563 | 2026-04-07 | Active | — |
| AMERICAN INSTALLMENT CREDIT CORPORATION | F003372 | 1946-05-29 | Withdrawn | — |
| AMERICAN INSTITUTE FOR CANCER RESEARCH, INC. | F020504 | 1989-04-14 | Active | — |
| AMERICAN INSTITUTE FOR SENSORY LADDER EDUCATION, LLC | C152376 | 2006-01-30 | Dissolved | GREAT FALLS |
| AMERICAN INSTITUTE OF BANKING - YELLOWSTONE CHAPTER, INC. | D043398 | 1976-08-03 | Dissolved | — |
| AMERICAN INSTITUTE OF BANKING GREAT FALLS CHAPTER, INC. | D042465 | 1976-01-09 | Dissolved | — |
| AMERICAN INSTITUTE OF HOLISTIC THEOLOGY, INC. | D095938 | 1998-09-04 | Merged | — |
| AMERICAN INSTITUTE OF MANAGEMENT AND TECHNOLOGY, INC | D128414 | 2003-12-02 | Dissolved | — |
| AMERICAN INSTITUTE OF PATHOLOGIC SCIENCE | D049950 | 1980-02-27 | Dissolved | — |
| American Institute of Sports Rehabilitation, LLC | C1048104 | 2017-06-22 | Active | — |
| AMERICAN INSTITUTE OF TOXICOLOGY, INC. | F075014 | 2015-03-02 | Withdrawn | — |
| AMERICAN INSTITUTES FOR RESEARCH IN THE BEHAVIORAL SCIENCES | F078197 | 2016-01-29 | Active | — |
| AMERICAN INSTRUMENTS, INC. | D1031883 | 2017-01-09 | Dissolved | — |
| AMERICAN INSURANCE & INVESTMENT CORP. | F025648 | 1994-08-11 | Active | — |
| AMERICAN INSURANCE ADMINISTRATORS LLC | E064985 | 2012-01-30 | Active | — |
| AMERICAN INSURANCE ADMINISTRATORS, INC. | F045193 | 2005-01-28 | Withdrawn | COLUMBUS |
| AMERICAN INSURANCE ADMINISTRATORS, INC. | F030204 | 1997-08-28 | Revoked | BROOMFIELD |
| AMERICAN INSURANCE AGENCIES, INC. | F024201 | 1993-06-07 | Revoked | RENO |
| AMERICAN INSURANCE BROKERS, LTD. | F023671 | 1992-12-14 | Revoked | CHICAGO |
| AMERICAN INSURANCE CENTER | D050633 | 1980-07-02 | Dissolved | — |
| AMERICAN INSURANCE COMPANY | F000345 | 1895-12-18 | Expired | — |