| Rank | Abbreviation | Meaning |
|---|
| ***** | MSSI | Modified Scale for Suicidal Ideation
| |
| *** | MSSI | Microsoft Shared Source Initiative
| |
| ** | MSSI | Management Systems Services, Inc.
| |
| * | MSSI | Mortgage Savings Solutions Inc
| |
| * | MSSI | Mountain States Specialties Inc
| |
| * | MSSI | Mainz Severity Score Index
| |
| * | MSSI | Micro Software Services Inc
| |
| * | MSSI | Macquarie Synthetic Sentence Identification
| |
| * | MSSI | Meggitt Safety System Inc
| |
| * | MSSI | Management Solutions Systems Inc
| |
| * | MSSI | Millenium Software Solutions Inc
| |
| * | MSSI | Ministry of Small Scale Industry
| |
| * | MSSI | Micro System Specialists Inc
| |
| * | MSSI | Mont Saint-Sauveur International
| |
| * | MSSI | Ministry of Small Scale Industries
| |
| * | MSSI | Management Services and Support Inc
| |
| * | MSSI | Medical Staffing Solutions, Inc.
| |
| * | MSSI | Medical Staffing Services Inc
| |
| * | MSSI | Mexican Social Security Institute
| |
| * | MSSI | Medical Science Systems Inc
| |
| * | MSSI | Michigan Statewide Systemic Initiative
| |
| * | MSSI | Mail Sender Service Interface
| |
| * | MSSI | Marangrio Space Services Inc
| |
| * | MSSI | Morrison Software Services Inc
| |
| * | MSSI | Medical Staffing Sol (OTC Bulletin Board [OTCBB])
| |