Heyday Films, 1492 Pictures
Warner Bros—one of the oldest and most prestigious studios in Hollywood—distributed Harry Potter and the Sorcerer's Stone, but the actual-factual production was divided between two companies: Heyday Films and 1492 Pictures.
Heyday's a British production company, set up in 1997 by producer David Heyman. He got started working as an assistant under the legendary British director David Lean (of Lawrence of Arabia fame) then landed a gig as the vice president at United Artists while venturing into the realm of independent film production.
That's telling: it shows us that Heyman's a guy who really loves making movies, and wants to do so without corporate influence…but still knows how to play Hollywood's game. Don't hate the player, etc.
And you could say he succeeded. He scored the rights to the Harry Potter films just a couple of years after founding Heyday, and served as the producer for each and every one of them. Harry Potter and the Sorcerer's Stone was only the second movie under its banner, so they tasted rarefied air pretty quickly. (Their first movie was a cannibal western called Ravenous, which earned approximately 40 gazillion dollars less than Harry Potter).
Heyman and his company have continued to produce a number of Hollywood blockbusters after Harry Potter, including the Will Smith horror movie I Am Legend and the "let's see if Sandra Bullock suffocates in the inky blackness of space" effort Gravity. Mr. Heyman, it seems, is kind of a big deal.
So is director Chris Columbus, whose own production company (1492 Pictures) got in on the action as well. Columbus set it up in 1995 to handle his various film projects—he'd gotten to be a reasonably big deal himself at that point—and chose the name as a riff on another famous person with his name. (We're betting he got razzed about it a lot in school.)
In addition to Columbus joints like the pregnant-women-make-their-boyfriends-freak-out comedy Nine Months and the not-even-Robin-Williams-can-sell-us-on-this-creepy-robot movie Bicentennial Man, the company has also handled production duties on the two Percy Jackson movies (the first of which Columbus directed as well), the three Night at the Museum movies, and the first two Fantastic Four movies (i.e., the ones that were merely not good instead of a full-on train wreck.)
It's safe to say that the Harry Potter films are the biggest things both production companies have done so far, so the call was probably a good one.