• Nike will be the exclusive uniform provider for the NBA and WNBA for another 12 years.
• The sneaker giant, which also designs uniforms for the MLB and NFL, has shored up its relationship with one of its most important allies as it struggles with falling sales and looks to hang on to its contract with the NFL.
• Nike's previous contract with the NBA was reportedly worth $1 billion and its latest contract is "much bigger," a person familiar with the matter told CNBC.

Nike will be the exclusive uniform and apparel provider for the National Basketball Association and Women's National Basketball Association for another 12 years after they renewed their partnership with the sneaker giant, the leagues announced Monday.

Under the terms of the deal, Nike will be the leagues' global outfitting, merchandising, marketing and content partner until 2037. The company will also be in charge of designing and manufacturing uniforms, on-court apparel and fan merchandise.

Nike's last deal with the basketball leagues, which kicked off during the 2017-18 NBA season, was reported to be worth $1 billion and marked the first time an apparel partner had its logo on an NBA or WNBA jersey. It is unclear how much Nike's contract renewal with the leagues is worth, but a source familiar with the deal characterized it as "much bigger" than the previous contract.

As the largest athletic apparel company in the world, Nike has long been a favorite among professional sports leagues and their athletes. Even so, its contract renewal with the NBA comes at a time when the sneaker giant has had to work harder to maintain its critical partnerships, and new CEO Elliott Hill tries to regain market share lost in recent years.

Nike is also the official uniform supplier of the National Football League and Major League Baseball, but those relationships have taken a hit as the company faces declining sales and criticism that it has fallen behind on innovation.

The NFL's deal with Nike expires after the 2027 season, but the league has opened up the process to other bidders and is already in talks with several companies interested in competing for the agreement, a source told CNBC.

Nike's contract with the MLB does not expire until 2029. However, it will have to repair its relationship with the league after it debuted new uniforms earlier this year that led to widespread complaints from players and fans that they were see-through, did not fit right and looked "amateurish," ESPN reported at the time.

Despite Nike's recent stumbles, the NBA told CNBC it has no concerns about continuing its partnership with the apparel company.

"From our perspective, we have 100% confidence in Nike on a long term global basis," said Sal LaRocca, the NBA's president of global partnerships. "They're endemic to basketball. They've been a partner of ours in one form or another for well over 30 years."

LaRocca added the partnership has been so strong that the league did not even open the process up to other bidders.

When asked about the MLB fiasco, LaRocca defended Nike and said those kinds of issues come with the territory.

"I think any company that is on the edge of innovation and is always looking to push the envelope for improvement may run into some unintended consequences," said LaRocca.

Nike has not faced significant criticism for its basketball uniforms. LaRocca said, "you'll certainly see fresh new products on a regular basis from them."

Nike has had a marketing partnership with the NBA since 1992 — and with the WNBA since its 1997 founding — and the brand endorses most of the leagues' biggest players, including LeBron James, Kevin Durant, Caitlin Clark and Sabrina Ionescu.

As of Friday's close, Nike's stock has fallen about 24% this year and has underperformed both competitors and the S&P 500, which has gained about 23% this year. On Running and Deckers, two companies that have been taking market share from Nike, are up 79% and 43%, respectively.

Historically, Nike has outperformed the S&P 500 by an average of about 8%.