- Paccar – from Pacific Car and Rail.
- PCCW – originally Pacific Century Development, the company's English name was changed from Pacific Century CyberWorks Limited to PCCW Limited on 9 August 2002. It owns Hong Kong Telecom.
- Pamida – U.S. retailer founded by Jim Witherspoon and Lee Wegener, it took its name from the first two letters of the names of Witherspoon's three sons: Patrick, Michael and David. It became a division of another American retailer, Shopko, in 2000, but is again a separate company after being spun off in 2007.
- Pemex – an abbreviation of the full name of the state-owned Mexican oil/gasoline company, Petróleos Mexicanos (Spanish for Mexican Petroleum).
- Pennzoil – formed by a merger of South Penn Oil (Penn), a former Standard Oil subsidiary, and Zapata Oil (zoil).
- Pepsi – named from the digestive enzyme pepsin.
- Petrobras – an abbreviation of the Brazilian oil company's full name, Petróleo Brasileiro (Portuguese for Brazilian Petroleum).
- Peugeot - named after Emile Peugeot.
- Philco – from the Philadelphia Storage Battery Company. The pioneering U.S. radio and television manufacturer was taken over by Ford and later by Philips.
- Philips – Royal Philips Electronics was founded in 1891 by brothers Gerard (the engineer) and Anton (the entrepreneur) Philips.
- Piaggio – the Italian company that produced the Vespa range of scooters and cars was named after its founder, Rinaldo Piaggio.
- Pioneer Corporation - In 1938, Nozomu Matsumoto, the son of a Christian missionary, founded Fukuin Shokai Denki Seisakusho ("Gospel Electric Works") to manufacture the A-8 loudspeaker, which he called "Pioneer". The company name was changed to the religiously neutral Pioneer Electronic Corporation in 1961, when it went public. In 1999, the company simplified its name by removing "Electronic".
- Pixar – from pixel and the co-founder's name, Alvy Ray Smith. According to the biography "The Second Coming of Steve Jobs" by Alan Deutschman, the 'el' in pixel was changed to 'ar' because 'ar' is frequently used in Spanish verbs, implying the name means "To Pix".
- PMC-Sierra – PMC from Pacific Microelectronics Centre, a research arm of BC Tel, and Sierra from the company that acquired it, Sierra Semiconductor, presumably so named because of the allure of the Sierra Nevada mountains to members of a California-based company.
- Porsche – car company named after founder Ferdinand Porsche, an Austrian automotive engineer. The family name may have originated in the Czech name "Boreš" (boresh).
- POW! Entertainment – American media production company co-founded by former Marvel Comics editor and publisher Stan Lee in 2001. POW! is commonly used in comic book fights, but it is used as an acroynm (or backronym) in the name POW! (Purveyors of Wonder) Entertainment, Inc.
- Prada – an Italian high fashion house named after the founder Mario Prada, who founded Prada in Milan 1914.
- PricewaterhouseCoopers – global professional services firm named as a result of the merger of Price Waterhouse and Coopers & Lybrand in 1998. It now trades as PwC, although its legal name remains the fully expanded form.
- Procter & Gamble – named after the founders, William Procter, a candlemaker, and James Gamble, a soapmaker, who pooled their resources after marrying two sisters. The company was founded in Cincinnati in 1837.
- ProfSat – Brazilian satellite-based education company, meaning Professional Sateliite.
- Proton – the Malaysian car manufacturer's name is derived from Perusahaan Otomobil Nasional, which means National Automobile Enterprise in the Malay language.
- PRS Guitars – named after its founder, Paul Reed Smith.
- Psion – UK computer company named by its founder, South Africa-born Dr David Potter, from Potter Scientific Instruments Or Nothing.
Read more about this topic: List Of Company Name Etymologies