Whilst it's unlikely that you'll ever see a company outright endorsing any software, they will often make use of contractors, freelancers and creative agencies that do.
In terms of big game devs - Insomniac Games, the creators of Spyro, Ratchet and Clank, and the upcoming PS4 Spider-Man game, have made prototypes in Construct.
In terms of creatives, I'm not as certain on this (so I won't name them) - but I believe a colleague made use of Construct as a Flash/Animate replacement for interactive content for one of UKs largest and most famous animation houses.
In terms of big corporates, I use Construct to produce prototypes and finished drafts - the largest company being a multinational that ranks very high on the top 10 of the Forbes Global 500; though as with all corporate clients, this was for a very isolated (though nontheless brand-named) division.
This.
Demo's in hours rather than days.
Creatives in days rather than weeks.