Jack Sock has switched to  Lululemon clothing. His contract with longtime sponsor Nike expired at the end of the year. He has been wearing Lululemon clothing and hat in his recent matches.

Jack Sock was ranked world number 8 in 2017 but has struggled with form and injuries since then. He found more success in doubles with three grand slam titles. In 2014, he won the Wimbledon doubles title with Vasek Pospisil. In 2018, he won the Wimbledon and US Open titles with Mike Bryan. The pair also went on to win the year-end ATP title.

Lululemon  recently signed up Canadian tennis sensation Leylah Fernandez. The company plans to expand into tennis-specific apparel soon. So it comes as no surprise that they signed up an American tennis player in Jack Sock.

Lululemon is a Canadian American company headquartered in Vancouver and domiciled in Delaware. It was founded in 1998. The company was initially known for its pants and yoga wear. It has since expanded into other athletic wear, accessories and personal products.