Kobe Bryant’s Nike Contract Expired. The Implications Are Complex.

The most popular shoes on the N.B.A. hardwood for the last several seasons were not the signature sneakers endorsed by the top active players, like Nike’s LeBron James or Adidas’s Damian Lillard. They were not the shoes endorsed by the man who practically invented the modern sneaker game, Michael Jordan.

Instead they were Nike’s line of Kobe Bryant’s signature sneakers, which were worn by 103 players last season — about 20 percent of the league’s players — according to the sneaker website Baller Shoes DB. Many W.N.B.A. players, like the Seattle Storm’s Jewell Loyd, also wear Bryant’s signature sneakers.

But soon those players will need to find new shoes, at least if they want to play in brand-new pairs. Nike confirmed Monday that its contract with the estate of Bryant, who died in a helicopter crash last year, expired last week.

“Kobe Bryant was an important part of Nike’s deep connection to consumers,” a Nike spokesman, Josh Benedek, said in a statement. “He pushed us and made everyone around him better. Though our contractual relationship has ended, he remains a deeply loved member of the Nike family.”

In the uncertainty over Bryant’s continued endorsement deal for basketball shoes and apparel, a number of issues collide: what professional basketball players wear on the court, the demand from consumers for Bryant merchandise and how a person’s name and image are used, even after their death.

Nike has a short window in which it can continue selling the shoes and apparel featuring Bryant that it has already manufactured, but soon that merchandise will disappear from Nike’s website and store shelves.

Switching shoe companies is not uncommon for top basketball players, whose sneaker contracts can pay tens of millions of dollars annually and rival or even exceed their N.B.A. contracts in value. Bryant signed with Adidas before he entered the N.B.A., in 1996, then signed with Nike in 2003 after his Adidas deal ended. Even as some major sponsors dropped Bryant when he was accused of sexual assault, Nike, which had signed Bryant shortly before he was arrested, stood by him.

The current situation with Bryant’s estate has no analogue in basketball or sneaker history. Signature basketball shoes really only began to gain prominence in the late 1980s, and barely any N.B.A. superstars from that era or later have died, let alone at a young age like Bryant, who was 41.

The closest comparisons are perhaps Chuck Taylor, the namesake of Converse’s famed Chuck Taylor All-Stars, whose shoes remain popular 50 years after his death, or Maya Moore, the W.N.B.A. star and Jordan Brand endorser, who has sat out the past few seasons to focus on social justice. But the strained analogies suggest the past provides little hint of what will happen next.

Almost all N.B.A. players are endorsed by one sneaker company or another. But only a handful have lines of shoes named after them, fewer have popular lines that sell tens or hundreds of millions of dollars worth of merchandise annually and even fewer stay popular in retirement. In the 1990s, a handful of W.N.B.A. stars had shoe deals, including Sheryl Swoopes, who was the first female athlete to have a signature basketball sneaker.

Nike clearly believed that Bryant’s appeal extended into retirement, signing him to a new five-year agreement on the day of his final N.B.A. game: April 13, 2016. Bryant played his final season in the Kobe 11s, the 11th edition of his sneaker line. After his retirement, Nike released a new line of sneakers styled as Kobe A.D., or anno Domini, the Latin phrase that means “in the year of the Lord.”

Nike’s Jordan brand, and its continued release of Air Jordan sneakers, remains quite popular, but as everyday fashion shoes; N.B.A. players rarely wear Air Jordans during games these days. Bryant attempted to buck that trend in retirement, with Nike releasing Bryant “protro” shoes: retro Bryant shoes updated with modern professional performance features.

While they were popular with basketball players, Bryant’s sneakers were not always the most popular off the court, worn with jeans or sweats.

Before Bryant’s death, the market for his shoes was fairly niche, said Chad Jones, the co-founder of Another Lane, a marketplace for sneaker collectors. “Performance wise, a lot of performance athletes loved Kobe shoes, but fashion wise is really the predictor for how well it will sell to the masses,” Jones said.

Nike did not sign Bryant to what is effectively a lifetime contract, like it has done with Jordan and James, raising questions about how much continued value it saw in his name. The Kobe shoes N.B.A. players wore were often limited editions or unique colors that average consumers could not buy, partly explaining why their popularity on the court did not necessarily translate to popularity on the street.

Since Bryant’s death, Nike has released new Bryant merchandise, but mostly in limited quantities through its SNKRS app. The shoes have sold out almost immediately, and then showed up for much higher prices on resale markets, leading to accusations that Nike was allowing resellers to profit from Bryant’s death.

“When people don’t get them on retail, but on a resale platform for five times or two times the price, they are upset,” Jones said.

In a statement posted to Instagram on Monday night, Vanessa Bryant, Kobe’s widow, wrote that she was “hoping to forge a lifelong partnership with Nike that reflects my husband’s legacy,” and hinted that she will find a way to continue to sell Bryant’s products, perhaps in greater quantities.

“My hope will always be to allow Kobe’s fans to get and wear his products,” she wrote. “Kobe’s products sell out in seconds. That says everything.”

If Vanessa Bryant cannot come to an agreement with Nike on a new contract, building a new brand around Kobe could be a challenge. Nike, including brands it owns like Jordan Brand and Converse, controls more than half the sneaker market, with companies like Adidas and Puma as distant competitors. Under Armour, which is endorsed by Golden State’s Stephen Curry, has struggled to break through.

Many sneakers are promoted through elaborate back stories about how the player inspired specific design details or guided the design process, and through player-focused advertising campaigns.

But what really sells sneakers is players’ connection to culture, or the feelings they evoke in potential consumers, not necessarily winning N.B.A. championships or a shoe’s performance features. Allen Iverson’s rebellious, me-against-the-world persona made his “Answer” shoes from Reebok popular sellers in the 2000s, even though he never won an N.B.A. title.

Bryant was not always a popular player, and his early shoes were not top sellers. Through repeated trips to China and success in the Olympics he found fame outside of America’s borders, and as he aged a generation of players entered an N.B.A. that revered him.

If the year since his death has shown anything, it is that even into retirement Bryant’s popularity was growing as he made new connections in Hollywood, opened a sports academy and became a prominent and vocal supporter of women’s basketball.