| Institut für Molekulare Biotechnologie | Academic & Science |
| Irvine, Michigan, and Brookhaven | Academic & Science |
| Institute of Molecular Biotechnology | Academic & Science |
| Illini Marching Band | Academic & Science |
| Institute for Marine Biochemistry | Academic & Science |
| Institute of MicroBiology | Academic & Science |
| Institute for Mind and Biology | Academic & Science |
| Institute of Molecular Biology | Academic & Science |
| Imbaimadai | Airport Code |
| International Merchant Bank | Banking |
| Independent Monitoring Board | Business |
| Instrument Material Bulletin | Business |
| Intercontinental Medical Book Corporation | Business |
| Inter-Mountain tariff Bureau | Business |
| Internationaler MetalarBeiterbund | Business |
| Internet Marketing Business | Business |
| Information Management Branch | Business |
| Illicit Massage Business | Business |
| Interactive Media and Business | Business |
| International Mission Board | Community |
| International Medieval Bibliography | Community |
| Integrated Media Block | Community |
| Imitation Bass | Community |
| Inter-module Bus | Computer Hardware |
| Input Memory Buffer | Computer Hardware |
| Integrated Mobile Broadcasting | Computing |
| Intelligent Mail Barcode | General |
| Illawarra Mutual Building | General |
| Induced Magnetosphere Boundary | General |
| Irvine Michigan Brookhaven | General |
| Ice Mass Balance | General |
| Industry Market Barometer | General |
| Ijin Mendirikan Bangunan | General |
| Integrated Master and Bachelor | General |
| Intelligent Mail Barcodes | General |
| Informelow Motivare Behevrowal | General |
| Intel MPI Benchmarks | General |
| International Maritime Bureau | Governmental |
| Insured Municipal Bond | Governmental |
| International Maritime Boundary | Governmental |
| Institute for Molecular Bioscience | Governmental |
| Irish Medicines Board | Medical |
| Intermenstrual bleed | Medical |
| I Am Back | Messaging |
| I Might Be .... | Messaging |
| Idaho Message Board | Messaging |
| Installation Management Board | Military and Defence |
| Independent Mixed Brigade | Military and Defence |
| Irvine / Michigan / Brookhaven Experiment | Physics Related |
| Imbaimadai Airport, Imbaimadai, Guyana | Regional |
