Rory McIlroy, Justin Thomas among Whoop Series E financing investors

What do Kevin Durant, Patrick Mahomes, Larry Fitzgerald, Rory McIlroy and Justin Thomas have in common?

Along with several venture capital funds, Whoop has announced they are private investors in a $100-million round of Series E funding for the human-performance company now valued at $1.2 billion.

In addition to McIlroy and Thomas, several professional golfers, including Billy Horschel and Xander Schauffele, began wearing a Whoop band either on their wrist or around their biceps in 2019. Whoop measures the wearer’s heart rate hundreds of times per second, and when paired with a smartphone app it reveals how hard an athlete has worked by measuring strain. Whoop also tracks how long the wearer sleeps, how restorative that sleep is and how recovered the wearer is when he or she wakes up.

Rory McIlroy typically wears his Whoop 3.0 strap around his left biceps. (AP/Charles Rex Arbogast)

Series E funding is rare and typically occurs when a company wants to stay private for an extended period and delay going public for various reasons.

Appearing on Golfweek’s Forward Press podcast in April, as the COVID-19 pandemic forced the United States and many other parts of the world to shut down, Whoop founder and CEO Will Ahmed said data the strap collects may be able to determine that a user is sick before the individual becomes symptomatic.

Whoop 3.0 strap (Whoop)

Two months later Whoop gained notoriety when Nick Watney woke up Friday morning before the second round of the RBC Heritage and his Whoop revealed his respiratory rate overnight had spiked. Respiratory rate is the number of times you breathe, something Whoop tracks, and studies showed Whoop wearers who see a significant increase in respiratory rate often are asymptomatically carrying the coronavirus. After requesting that the PGA Tour test him before he played, it was confirmed Watney had COVID-19.

Nick Watney, wearing a blue Whoop 3.0 strap on his right wrist, in January 2020 (Orlando Ramirez-USA TODAY Sports)

The following week at the Travelers Championship, the PGA Tour announced a partnership with Boston-based Whoop and made bands available to all players, caddies and many tournament officials.

In the weeks that followed, Whoop partnered with the LPGA and Symetra tours as well.

According to a release, Whoop has hired more than 200 people in 2020 and has over 330 employees. It has raised more than $200 million to date.