Originally, BioWare was a company that made RPG's exclusively for Interplay. Their first line of games were for Interplay. This included the ever popular, Baldur's Gate.
Then Interplay's financial troubles struck in, Interplay was supposed to publish Neverwinter Nights, but it didn't happen. Instead Atari did it. This made sure that BioWare never developed a game for Interplay again.