| Intensive English Studies | Academic & Science |
| Institute of Ecosystem Studies | Academic & Science |
| Institute for Experimental Studies | Academic & Science |
| Institute of Economic Studies | Academic & Science |
| Institute for Environmental Science | Academic & Science |
| Institute of Economy Studies | Academic & Science |
| Instrumentation Electrical Services | Academic & Science |
| Integrated Electrical Services | Academic & Science |
| Innovative Engineering Systems | Academic & Science |
| International Education for Students | Academic & Science |
| International Enescu Society | Academic & Science |
| Illumination Engineering Society | Academic & Science |
| Interstate Electronic Systems | Academic & Science |
| Riesa | Airport Code |
| Ideal Educational Society | Associations & Organizations |
| Integrated Establishment System | Banking |
| Indrema Entertainment System | Business |
| Internet Escrow Services | Business |
| Interior Exterior Specialists Construction Group, Inc. | Business |
| Intelligent Evacuation System | Chemistry |
| Indian Education Society | Community |
| International Education Services | Community |
| International Educational Studies | Community |
| International Educational Services | Community |
| Information Exchange System | Computing |
| Individual Experts | Computing |
| Inter Enterprise System | Computing |
| Intelligent Emulation Switching | Computing |
| Incoming e-Mail Solution | Computing |
| Integrated Enterprise Solutions | Computing |
| Integrated Enterprise System | Computing |
| Illuminating Engineering Society | Electronics |
| Institution of Engineers Singapore | Electronics |
| Integrated Earth Systems | General |
| Ion and Electron Sensor | General |
| Industry Expansion Solutions | General |
| Innovative Event Services | General |
| Innovative Event Solutions | General |
| Industrias Eduardo Sal-Lari | General |
| Integriertes Elektronik System | General |
| Idle Enrichment System | General |
| Intrepid es | General |
| Industrial Extension Service | General |
| In Eigener Sache | General |
| Integrated Eyewear System | General |
| Intelligent and Evolutionary Systems | General |
| Inland Empire Section | General |
| International Exchange Site | Governmental |
| Intelligence Evaluation Staff | Governmental |
| Institute of Educational Sciences | Governmental |
| Institute of Education Sciences | Governmental |
| Integrated Environmental Systems | Governmental |
| Institute of Environmental Sustainability | Governmental |
| Institute for Economic Stud | Governmental |
| Indoor Environmental Services | Governmental |
| Integrated Environmental Solutions | Governmental |
| Institute for the Environment and Sustainability | Governmental |
| Institute for Excellence in Sales | Governmental |
| Indian Engineering Services | Indian Government |
| International EPR Society | International |
| International Equipment Solutions | International |
| Internet Enrollment Services | Internet |
| Internet Event Server | Internet |
| Indian Engineering Service | Jobs |
| Internal Eliminated Sequence | Medical |
| Imagery Exploitation System | Military and Defence |
| Infantry Enhancement Suit | Military and Defence |
| Imagery Exploration System | Military and Defence |
| Industrial Electronics Society | Organization |
| Intra-Europe Service | Regional |
| Institute for European Studies | Regional |
| Institute of European Stud | Regional |
