Then and now: What tech CEOs and founders looked like when they first launched their companies versus today

Elon Musk today runs several more companies than he did in 1999, when the photo on the left was taken.AP / Richard Bord/WireImage via Getty Images

• Some of Silicon Valley's biggest names are in their tech bro era.
• It wasn't always like this — many Big Tech CEOs have shed more nerdy personas from their startup days.

Mark Zuckerberg isn't the only tech CEO whose style has noticeably evolved over the years.

Other Big Tech leaders have significantly changed up their looks since starting their companies; some are nearly unrecognizable (we're looking at you, Jeff Bezos.)

Here's a look at the style transformations of some of tech's biggest names: