| AON RISK SERVICES SOUTHWEST, INC. | 0000063308 | 2000-05-19 | Active | CHICAGO |
| AON RISK SERVICES, INC. OF ARIZONA | 0000084319 | 2006-09-13 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF ARKANSAS | 0000065733 | 2004-03-11 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF CENTRAL CALIFORNIA INSURANCE SERVICES | 0000028938 | 1994-08-05 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF COLORADO | 0000038238 | 1992-01-17 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF CONNECTICUT | 0000056996 | 1999-03-05 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF CONNECTICUT | 0000049209 | 1996-10-14 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF FLORIDA | 0000107303 | 2011-05-25 | Active | CHICAGO |
| AON RISK SERVICES, INC. OF GEORGIA | 0000063758 | 2000-07-21 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF INDIANA | 0000059246 | 1999-06-03 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF KANSAS | 0000059906 | 1999-08-04 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF KANSAS | 0000039920 | 1994-12-27 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF KENTUCKY | 0000028457 | 1993-11-05 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF MARYLAND | 0000030249 | 1990-11-15 | Active | CHICAGO |
| AON RISK SERVICES, INC. OF MASSACHUSETTS | 0000067587 | 2001-10-02 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF MICHIGAN | 0000065208 | 2000-11-30 | Merged | DETROIT |
| AON RISK SERVICES, INC. OF MINNESOTA | 0000060086 | 1999-08-06 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF MINNESOTA | 0000049630 | 1996-11-29 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF NEBRASKA | 0000059943 | 1999-09-20 | Merged | OMAHA |
| AON RISK SERVICES, INC. OF NEBRASKA | 0000031845 | 1994-03-14 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF NEW JERSEY | 0000066101 | 2001-03-01 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF NEW MEXICO | 0000074004 | 2003-03-11 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF NEW YORK | 0000033057 | 1991-05-22 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF OHIO | 0000057399 | 1998-12-14 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF OKLAHOMA | 0000004397 | 1994-06-01 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF OREGON | 0000061587 | 2000-01-04 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF OREGON | 0000046957 | 1996-02-29 | Dissolved | CHICAGO |
| AON RISK SERVICES, INC. OF PENNSYLVANIA | 0000030078 | 1994-09-09 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF PENNSYLVANIA | 0000061677 | 2000-02-08 | Dissolved | CHICAGO |
| AON RISK SERVICES, INC. OF SOUTHERN CALIFORNIA INSURANCE SERVICES | 0000033493 | 1991-06-05 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF SOUTHERN CALIFORNIA INSURANCE SERVICES | 0000050236 | 1997-01-24 | Dissolved | CHICAGO |
| AON RISK SERVICES, INC. OF UTAH | 0000033069 | 1991-05-22 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF WASHINGTON | 0000074500 | 2003-04-28 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF WASHINGTON,D.C. | 0000064979 | 2000-11-17 | Active | CHICAGO |
| AON RISK SERVICES, INC. OF WISCONSIN | 0000061355 | 1999-12-28 | Merged | CHICAGO |
| AON RISK SERVICES, INC. OF WISCONSIN | 0000031384 | 1995-03-16 | Dissolved | CHICAGO |
| AON SELECT, INC. | 0000048910 | 1996-09-11 | Merged | CHICAGO |
| AON SERVICE CORPORATION | 0000056546 | 1998-09-24 | Active | CHICAGO |
| AON TECHNICAL INSURANCE SERVICES, INC. | 0000048688 | 1996-09-26 | Merged | CHICAGO |
| AON/ALBERT G. RUBEN INSURANCE SERVICES, INC. | 0000000122 | 1994-07-22 | Active | CHICAGO |
| AONE FOUNDATION FOR NURSING LEADERSHIP RESEARCH AND EDUCATION | 33330900 | 2013-01-03 | Active | CHICAGO |
| AONL Foundation for Nursing Leadership Research and Education | 0000124225 | 2013-01-03 | Active | CHICAGO |
| AOPA AIR SAFETY FOUNDATION | 0000073382 | 2003-02-19 | Dissolved | FREDERICK |
| AOPA INSURANCE AGENCY, INC. | 0000029275 | 1994-08-30 | Dissolved | FREDERICK |
| AOPA INSURANCE AGENCY, INC. | 0000042199 | 1993-05-14 | Dissolved | WICHITA |
| AOPA INSURANCE AGENCY, INC. | 0000118591 | 2012-08-16 | Dissolved | WICHITA |
| AORN FOUNDATION | 0000108821 | 2011-07-26 | Active | DENVER |
| AORN WORKS, INC. | 0000093552 | 2009-03-12 | Dissolved | DENVER |
| AOS ENGINEERING, LLC | 0006471297 | 2023-11-15 | Active | FARGO |
| AOS ENGINEERING, LLC | 0000139689 | 2014-08-18 | Dissolved | PLANO |