Every CEO has their own "unique" sense of style.
The late Steve Jobs never went anywhere without his always buttoned, never belted trusted jeans and turtleneck, while ol' Steve Ballmer prides himself on his polo necks, which he lovingly alternates in colour and style.
However, there's a new kid on the fashion block, looking to take the tech style crown from right under these CEO's feet - and that's the young Mr Zuckerberg.
It wouldn't be hard for the Facebook CEO to rise to the top of the Facebook fashion brat pack.
He hasn't got the paunch of Mr Ballmer, or Paul S Otellini's eyewear. He could carry off that sleek tailored Prada suit and show off those eyes - perhaps with a tinge of eyeliner - since it's the fashion now.
But Zuckerberg has his own line of style in mind. And that's - wait for it - pyjamas.
The CEO turned up at a meeting with prospective investor Sequoia Capital wearing the nightwear. Not only is this the most unprofessional you can get but also a terrible faux pas.
In fact it's a cardinal fashion sin with this attire even being banned in Tescos - Mark, that really says something.
Now, experts are claiming that the Facebook chief needs to fix up, and look sharp if he wants to impress the fat cats.
Michael Pachter, an analyst for Wedbush Securities, told Bloomberg TV that the hoodie and casual attire did not show investors that Zuckerberg was serious about business.
Perhaps dressing like a college kid makes Zuckerberg feel young, or perhaps he's going for the more down and out look, not looking out of place in Zooland's Derelicte - perhaps if he looks the part people may bung him a pound or two.
It seems to have worked as the CEO is worth billions. Now, where did we put those old sweatshirts and trackies?