As the FTX cryptocurrency trade imploded final fall, Tom Brady, the seven-time Super Bowl-winning quarterback, made an pressing telephone name.

He dialed Sina Nader, FTX’s head of partnerships. The trade’s employees was in the midst of a disaster assembly with its beleaguered founder, Sam Bankman-Fried. Mr. Nader couldn’t reply. “I never would’ve expected to decline a call from Tom Brady,” he mentioned.

Mr. Brady had causes to be involved. As an “ambassador” for FTX, he had appeared on the firm’s convention within the Bahamas and in TV commercials that promoted the trade as “the most trusted” establishment within the loosely regulated world of crypto.

His cash was additionally at stake. As a part of an endorsement settlement Mr. Brady signed in 2021, FTX had paid him $30 million, a deal that consisted nearly fully of FTX inventory, three folks with information of the contract mentioned. Mr. Brady’s spouse on the time, the supermodel Gisele Bündchen, was paid $18 million in FTX inventory, one of many folks mentioned.

Now FTX is bankrupt, and Mr. Bankman-Fried is going through legal fraud fees. Mr. Brady, 45, and Ms. Bündchen, 42, have been sued by a bunch of FTX prospects searching for compensation from the celebrities who endorsed the trade. On high of all of it, the phrases of the deal would have required the previous couple, who divorced final 12 months, to pay taxes on at the very least a few of their now nugatory FTX inventory, two folks acquainted with the endorsement deal mentioned.

Their state of affairs is the highest-profile instance of a humiliating reckoning going through the actors, athletes and different celebrities who rushed to embrace the straightforward cash and on-line hype of cryptocurrencies. During the growth instances, Paris Hilton, Snoop Dogg, Reese Witherspoon and Matt Damon all gushed about or invested in crypto tasks, bringing a mainstream viewers to the wonky world of digital currencies. It was enjoyable — and profitable — whereas costs soared.

But last year’s crash ended the movie star crypto bonanza.

In October, the Securities and Exchange Commission ordered Kim Kardashian to pay $1.26 million for failing to make satisfactory disclosures when she endorsed the EthereumMax crypto token. In December, a lawyer in California sued two crypto corporations, MoonPay and Yuga Labs, accusing them of utilizing a “vast network of A-list musicians, athletes and celebrity clients” to mislead traders about digital belongings.

In March, the S.E.C. charged the actress Lindsay Lohan, the net influencer Jake Paul and musicians together with Soulja Boy and Lil Yachty with illegally selling crypto belongings. And in late May, after months of failed makes an attempt, a course of server delivered court papers to Shaquille O’Neal, the retired basketball star, who was sued for selling FTX, in accordance with authorized filings. Mr. O’Neal was served whereas broadcasting from a National Basketball Association playoff recreation.

Representatives for Mr. Brady, Mr. Bankman-Fried and MoonPay declined to remark. A spokeswoman for Yuga Labs mentioned the corporate had “never paid a celebrity to join the club.” Representatives for Ms. Bündchen and Mr. O’Neal didn’t reply to requests for remark.

Tech start-ups and celebrities have lengthy had a symbiotic relationship. The start-ups supply stars a method to earn cash whereas staying on the chopping fringe of web tradition; the celebrities assist younger corporations achieve credibility and attain a bigger viewers.

Of all of the start-ups that recruited celebrities to endorse crypto, FTX was maybe probably the most keen. As Mr. Bankman-Fried tried to show FTX right into a family title, he made an inventory of celebrities he may envision selling the corporate, recalled Mr. Nader, the previous FTX govt. Mr. Brady’s title was on the high.

A former faculty soccer participant, Mr. Nader was accountable for recruiting Mr. Brady and different stars. In June 2021, Mr. Brady and Ms. Bündchen agreed to a deal with Mr. Bankman-Fried, praising the “revolutionary FTX team.” Mr. Brady appeared genuinely involved in crypto, Mr. Nader mentioned, and sometimes had conversations with Mr. Bankman-Fried.

“Imagine a tiger and a lion talking,” Mr. Nader mentioned. “They’re slightly different, they do different things, but they’re really formidable in their own arenas.”

In 2021, Mr. Brady additionally co-founded Autograph, which helps well-known folks promote the crypto collectibles generally known as nonfungible tokens, or NFTs. Autograph raised greater than $200 million from traders, and Mr. Bankman-Fried joined the board.

That similar 12 months, Mr. Brady and Ms. Bündchen starred in a $20 million promoting marketing campaign for FTX, with commercials that ran throughout N.F.L. video games. Mr. Brady additionally posted TikTok videos with Mr. Bankman-Fried from FTX’s headquarters within the Bahamas, the place he spoke at a convention in entrance of a whole bunch. Backstage, Mr. Bankman-Fried remarked that he may think about shopping for a soccer crew sometime with Mr. Brady. Ms. Bündchen additionally appeared on the convention as FTX’s head of environmental and social initiatives.

When FTX collapsed final November, the corporate’s $32 billion valuation — together with Mr. Brady and Ms. Bündchen’s $48 million of shares — plummeted to zero. The couple had additionally acquired a small quantity of Ethereum, Bitcoin and Solana tokens to commerce on the platform, one of many folks mentioned, which disappeared in FTX’s chapter.

Mr. Brady has not commented publicly on FTX or his relationship with Mr. Bankman-Fried. After FTX’s disaster assembly in November, Mr. Nader known as him again.

“He was concerned,” Mr. Nader mentioned. “The very first thing he asked me was: ‘Sina, how are you doing? I know you put your heart and soul into this.’”

Ms. Bündchen mentioned in a March interview with Vanity Fair that she had “trusted the hype” and felt “blindsided.”

Mr. Brady’s different crypto enterprise has additionally struggled. Autograph’s income sank final 12 months amid the crypto meltdown, an individual acquainted with its funds mentioned. The start-up has shifted its technique to focus extra on serving to celebrities discover methods to foster loyalty with their followers, and fewer on advertising and marketing crypto tokens to customers, the particular person mentioned. The agency has additionally eliminated some crypto language from its advertising and marketing, downplaying phrases like NFT, one other particular person with information of the corporate mentioned.

Autograph has additionally minimize greater than 50 staff in layoff rounds, a 3rd particular person mentioned. The reductions had been reported earlier by Insider. An Autograph spokeswoman declined to remark.

Mr. Brady has additionally confronted authorized bother. In December, Adam Moskowitz and the regulation agency Boies Schiller Flexner filed a lawsuit in federal court docket in Florida accusing him and Ms. Bündchen of deceptive traders. Among the opposite defendants are the comic Larry David, the N.B.A. star Steph Curry and the tennis participant Naomi Osaka, all of whom endorsed FTX.

“None of these defendants performed any due diligence prior to marketing these FTX products to the public,” the lawsuit mentioned.

Some celebrities narrowly escaped the crypto mess. Katy Perry, the pop star, held talks a few partnership with FTX that by no means got here to fruition, three folks acquainted with the state of affairs have said.

In spring final 12 months, Taylor Swift mentioned a cope with FTX that would have paid as a lot as $100 million, two folks acquainted with the matter mentioned. A tour sponsorship was on the desk after Ms. Swift declined different promotional choices, an individual with information of the talks mentioned. The deal’s measurement was reported earlier by The Financial Times.

Mr. Moskowitz, the lawyer suing the celebrities, said on a podcast in April that Ms. Swift had performed due diligence on FTX, asking the trade to show that its cryptocurrencies weren’t unregistered securities. His feedback led to a flurry of headlines about Ms. Swift’s enterprise acumen. But in an interview with The New York Times, Mr. Moskowitz mentioned he had no inside details about the talks.

In actuality, Ms. Swift’s facet signed the sponsorship settlement with FTX after greater than six months of discussions, three folks with information of the deal mentioned, and it was Mr. Bankman-Fried who pulled out. The last-minute reversal left Ms. Swift’s crew pissed off and disenchanted, two of the folks mentioned.

A spokeswoman for Ms. Swift declined to remark.