What billionaires and CEOs are wearing at this year's Sun Valley conference: Red, white, and corporate vests

While t-shirts in tech are nothing new, they have gotten an upgrade.

T-shirts, like the one worn by OpenAI CEO Sam Altman, are now heavier and more fitted, rather than the $20 Hanes worn by coders in their college days.

"Now it's thick enough, durable, and quality enough that it's the outer layer," Victoria Hitchcock, a San Francisco Bay Area fashion and lifestyle brander, told Business Insider.

Stacey Bendet Eisner, the CEO of the Alice + Olivia fashion brand, routinely has some of the most eye-catching outfits at Sun Valley.

"Do you think that Mark Zuckerberg gets his makeup done on his way to Sun Valley at 4:30 in the morning, too?" she pondered in a video posted to Instagram.

Political analyst Van Jones arrived in a red sweater — a splash of brightness among the more muted tones typical for the event. The inspiration comes straight from the runway, Hitchcock said, pointing to recent collections from Marni and Valentino.

When it comes to the Sun Valley Conference, there's no shame in sporting branded merch. Many attendees could be seen in red Allen & Co. zip-ups or carrying them in case it got chilly.

"You can't go wrong," Hitchcock said about choosing the branded gear. "These are the same people who were wearing the logos of their own companies forever and ever."

Fashion designer Diane Von Furstenberg was among a handful of attendees wearing gold chain jewelry — a trend that Meta CEO Mark Zuckerberg has also recently adopted.

"You see it everywhere — that layered, chunky gold," Hitchcock said.

Brian Grazer, cofouner of Imagine Entertainment, and media exec Barry Diller were seen sporting yellow lenses, while CBS news anchor Gayle King made a splash with her bright green frames.

While Shari Redstone, Bob Iger, and Tim Cook, of course, were spotted wearing Apple Watches, and a few Whoops were to be seen, many attendees wore old-fashioned wristpieces and ditched the computerized ones or tracking devices.

"They are super functional, and everyone I interact with owns them," Hitchcock said of Apple Watches. "But it doesn't keep them from purchasing some of those kind of pieces that are precious and have emotional attachment."

Fashion rules don't discriminate. Regular people and media moguls alike only have three months to wear white. So, Sun Valley is a prime time for attendees to don their best classic colorless looks — like this Phoebe Philo one on Oprah.

Jeff Bezos' fiancée Lauren Sanchez wore an quilted miniskirt for the conference, though she did pair it with sneakers for a more informal look.

And Bezos himself kept it classic Sun Valley in a t-shirt and vest. Turns out, despite some snazzier recent looks from Bezos, you can take the tech bro out of the basement — but you can't take the basement out of the tech bro.