| Pacific Training Institute | Academic & Science |
| Polish Informaticians Society | Academic & Science |
| Polskie Towarzystwo Informatyczne | Academic & Science |
| Part Time Interest | Accounts and Finance |
| Pre-tax Income | Accounts and Finance |
| Power Take In | Accounts and Finance |
| Port Douglas | Airport Code |
| Plastic Technologies Inc | Business |
| Polymer Technologies Inc | Business |
| Path To Item | Business |
| Precision Trust And Innovation | Business |
| Power Technologies Incorporated | Business |
| Production Technology Integrated | Business |
| Personnel Transaction Identifier | Business |
| Technologies Inc | Business |
| Power Tool Institute | Business |
| Part-Time Instructor | Business |
| Patheon Incorporated (de-listed) | Business |
| Professional Transportation, Incorporated | Business |
| Paper Transport Inc | Business |
| Proteostasis Therapeutics Inc | Business |
| Professional Theatre Initiative | Community |
| Parent Teacher Interview | Community |
| Publication Television And Internet | Community |
| Pakistan Tahriq-e-Insaf | Community |
| Precision Technology Institute | Computing |
| Planter Technology Institute | Computing |
| Parallel Technologies Inc. | Computing |
| Portable Test Instrument | Computing |
| Panel Link Tv-Out Interface | Computing |
| Packet Type Identifier | Computing |
| Payload Type Identifier | Computing |
| Promise Technology Inc. | Computing |
| Public Technical Identifier | Computing |
| Packet Trace Interface | Computing |
| Power Technologies International | Computing |
| Petroleum Training Institute | Country Specific |
| Panel Type Integration | General |
| Pre Trip Inspection | General |
| Public Technical Identifiers | General |
| Pathway Targeted Immunization | General |
| Parameter Tuning Interface | General |
| Pass Through Income | General |
| Product Traceability Initiative | General |
| Page Table Isolation | General |
| Pattern Triggered Immunity | General |
| Peers Trends and Incrementals | General |
| Pardon The Ignorance | General |
| Periodic Technical Inspection | General |
| Power Transfer Index | General |
| Perl Training Israel | General |
| Parents Training And Information | General |
| Proof Tracking Index | General |
| Pardon The Interuption | General |
| Pretend That I | General |
| Profit Taking Index | General |
| Personal Telephone Integration | General |
| Pre Trial Intervention | General |
| Propane Transport International | General |
| power take in In | General |
| Piedmont Triad International | General |
| Permit To Install | General |
| Parent Training and Information | General |
| Perpetual Testing Initiative | General |
| Properly Trained Idiots | General |
| Pakistan Tehreek i | General |
| Prostitute Traning Institute | General |
| Positive Target Identification | General |
| Part Time Indian | General |
| Pretrial Intervention in | General |
| Professional Transportation Inc | Governmental |
| Planning, Training, and Inspections | Governmental |
| Police Training Institute | Governmental |
| Physical Training Instructor | Governmental |
| Pakistan Tehrik-e-Insaf | Governmental |
| Pittsburgh Technical Institute | Governmental |
| Post Tensioning Institute | Governmental |
| Pakistan Tehreek-e-Insaf | Governmental |
| Pakistan Tehreek-e-Insaf (Pakistan) | Governmental |
| Pennsylvania Transportation Institute | Governmental |
| PATIALI | Indian Railway Station |
| Phoenix Tower International | International |
| Prova Trade International | International |
| Prostate Tumor Inducer | Medical |
| Pardon The Interruption | Messaging |
| Press Trust of India | Non-Profit Organizations |
| Preliminary Test Information | Space Science |
| Pre-programmed Test Input | Space Science |
| Programmed Test Input | Space Science |
| Produce Traceability Initiative | Sports |
| Pervasive Technology Institute | Technology |
| Photon Technology International | Technology |
| Public Technology Institute | Technology |
| Payload Type Indicator | Telecommunication |
