PepsiCo has increased its stake in Celsius to 11% with an additional $585 million investment, solidifying their strategic partnership. Celsius has acquired the Rockstar Energy brand from PepsiCo and will now lead PepsiCo's energy drink portfolio in the U.S., including Celsius, Alani Nu, and Rockstar Energy, while PepsiCo handles distribution. This move positions Celsius for significant growth within the energy drink market, leveraging PepsiCo's distribution network.