I know it's a weird question since everyone classifies them as "indie games", and Robin and Maarten started together from nothing and all that...

But the thing is, that's not actually that true ?
In 2015 Robin created the LoyaltyGame company which owns a few dutch miniclip-like sites.
Inside that company, at around the same time, they created a second company, called Rusty Lake, that is a sub-company of LoyaltyGame
And a little while back, they created a 3rd sub-company, this time owned by Rusty Lake, called Second Maze, for the release of The White Door

So, considering that technically, Rusty Lake is a company dependant of LoyaltyGame, and that at this point they're legitimately creating puppet companies....

Can they still be considered to be "independant" ?