1. Companies starting with P:

      Palace Software
      Pandemic Studios
      Paprikari
      Papyrus
      Paradox Interactive
      Paragon Software
      Parallax Software
      Paramount Interactive
      Parker Brothers
      Passfield Games
      PBI
      PC Software
      PDP-10
      Peachware
      Pearson Software
      Pel/Tek
      Penguin Programs
      Penguin Software
      Perfect Dork Studios
      Personal Software
      Petroglyph
      Phantagram
      Phenomic Game Development
      Philips
      Phoenix Games
      Piccadilly Software
      Pinnacle Software
      Piranha Bytes
      Pivotal Games
      Pixel Junk
      Pixel Tales
      Plastic Reality Technologies
      PlatinumGames
      Play Logic
      Player X
      PlayFirst
      PlayOnline
      Playrix Entertainment
      PM Studios
      PoBros
      Pocketwatch Games
      Polarware
      Pop Cap
      Popcap
      PopTop
      PortableApps
      Positech Computing
      Positech Games
      Positive Games
      Postcraft
      Prairie Games
      Precision Games
      Precocious Software
      Prestel
      Presto Studios
      Primate Games
      Private Moon Studios
      Processor Technology
      Programmers Software
      Progressive Computer Applications
      Project Aces
      ProSIM
      Prosoft
      Psyclapse
      Psygnosis
      Publishing International
      Pumpkin Studios
      Push Button Software

      Note: bolded names indicate companies that released a game within the last twelve months.