| Abbreviation | Definition |
|---|---|
| AHG | Apria Healthcare Group, Inc. |
| AHI | Allied Holdings, Inc. |
| AHO | Koninklikje Ahold, N. V. |
| AHP | American Home Products Corporation |
| AHR | Anthracite Capital, Inc. |
| AIB | Allied Irish Banks, P. L. C. |
| AIC | Asset Investments Corporation of Delaware |
| AIF | Acceptance Insurance Companies, Inc. |
| AIFPT | Acceptance Insurance Companies, Inc., Capital Trust |
| AIG | American International Group, Inc. |
| AIN | Albany International Corporation |
| AIR | A A R Corporation |
| AIRI | Air Industries Group, Inc. |
| AIV | Apartment Investment & Management Company |
| AIVPD | Apartment Investment & Management Company Preferred D |
| AIVPG | Apartment Investment & Management Company Preferred G |
| AIVPH | Apartment Investment & Management Company Preferred H |
| AIVPK | Apartment Investment & Management Company Preferred K |
| AIZ | Amcast Industrial Corporation |
| AJA | Appalachian Power Company Class A |