Here's your Forbes Daily Briefing for Sunday, April 13th.

Today on Forbes, founders of Allo Yoga, a hit with celebs like Taylor Swift and Haley Bieber, are billionaires.

On February 2nd, Haley Bieber was photographed walking into an Allo store in Manhattan,

sporting a black puffer jacket and a pair of the

brands just dropped limited edition charcoal green airlift leggings. Three days later, the New York

Post's gossip site, page six, ran a short article on the new leggings with the pictures of Bieber

and an affiliate link where shoppers could click and buy the $128

leggings. In the hotly contested battle for trendiest yoga wear, Allo is wooing and winning

over many famous fans and using them as part of its marketing push. Taylor Swift, Bella Hadid,

NFL quarterback Joe Burrow, and a long list of influencers

have all been photographed in everything from its $68 biker shorts to a $1,400 custom suit.

On its website, there is a section devoted to, quote, as seen on Kendall and Kylie,

referring to the famous Jenner Sisters.

There's another section featuring

Gisu, a member of K-pop girl band Black Pink, enjoying Allo and the West Coast before her

summer world tour. The Jenner sisters and Jisu are paid to promote Allo, but most of the other

celebs spotted wearing the clothes are doing so because they want to,

according to a company spokesperson.

This glamorous guerrilla marketing has helped Allo become a fast-growing challenger in the competitive

athleisure category, known for its younger skewing, street-cheek styles.

Referring to the brand, Alexandra Barash, a professor of marketing at the

University of Colorado Boulder's lead school of business, says, quote, it gives off that vibe of

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