Rich people who shopped too much used to be called collectors. Now they — and those belonging merely to the aspirational class — are all investors.

It’s not just that they’ve spent the last year splurging on stakes in untested, newly formed public companies that have yet to produce products, much less profits. It’s that during the pandemic, seemingly every luxury acquisition has become a so-called alternative asset class.

Rather than elbowing past each other for reservations at the latest restaurants from Marcus Samuelsson and Jean-Georges Vongerichten, or getting into bidding wars for apartments at 740 Park Avenue, they are one-upping each other in online auctions for jewelry, watches, furniture, sports cards, vintage cars, limited-edition Nikes and crypto art.

Bread lines grew longer, Birkin bags got hotter.

A number of retailers were reticent to speak about the trend, stating that they did not wish to be on the record talking about nearly sold out $90,000 earrings during a time of growing wealth inequality.

John Demsey, the executive group president of the Estée Lauder Companies, voiced that concern even as he admitted a primary quarantine pastime.

“All I do is go through watch porn,” he said. “I’m selling watches, I’m buying watches. It’s crazy. I have no reason right now to buy a watch. I’m at home all day at a computer. Time is staring me right in the face. What reason do I have to look at my wrist? But I want a tangible sign of something, so I’m looking at watches.” And many other people are too.

Rolex Day-Dates that sold on the secondary market in 2020 for $30,000 are now going for upward of $50,000 on some resale sites. The Nautilus 5980, a rose gold chronograph sports watch from Patek Philippe that has a retail price of $85,000, can seldom be found on 47th Street for much less than $200,000.

One reason for surging prices, according to Benjamin Clymer, the editor of the watch site Hodinkee, is that “Switzerland shut down, so demand was there while the supply was dramatically reduced.”

But also, he said, “the wealthy that used to spend money on travel aren’t using it, so everything collectible is skyrocketing in value.”

Coffee Tables and Porsches

That includes cars, a hobby that began for Mr. Clymer in 2011 and took off in 2015, when a multimillion-dollar strategic investment in Hodinkee helped transform him from blogger to mogul.

In the summer of 2020, Mr. Clymer went searching for a 1973 Porsche 911 Carrera RS.

One had sold shortly before the pandemic through the auction site Bring a Trailer (or BaT, as it’s known) for $560,000 but Mr. Clymer figured it might be a buyer’s market. Perhaps he could get it for less.

He found a beauty from a dealership that hadn’t listed the price on its website. It was in mint condition. Mr. Clymer asked for a quote and nearly fainted upon hearing the answer: $1.2 million.

“I said, ‘You’re crazy.’ Less than a month later it was sold.”

By Thanksgiving, auction houses were sending out news releases almost daily touting their record-breaking sales.

A pair of Conoid lounge chairs from the famed woodworker George Nakashima, which in 2019 commanded around $10,000, sold in October 2020 for $23,750 through the Chicago auction house Wright. A Mesa coffee table by T.H. Robsjohn Gibbings, a British architect whose name is barely known outside of the furniture world, brought in $237,500 in December; the overall result of the sale was $2.5 million, roughly double what the house did at the same sale a year before.

In February, a digital artwork of Donald Trump facedown in the grass, covered in words like “loser,” sold for $6.6 million, a record for a nonfungible token, or NFT, so called because there’s no physical piece for the buyer to take possession of.

Fittingly, the image was paid for in Ethereum, a form of cryptocurrency that, among millennials, is almost as well known as bitcoin. Two weeks later, Christie’s sold another NFT by Beeple, this time for $69 million.

The prices for the best vintage sports cards reached Warhol levels. In January, a 1952 Mickey Mantle was sold through PWCC Marketplace for $5.2 million. In March, Goldin Auctions, a sports collectible site, held its annual winter auction. “We grossed $45 million,” said Ken Goldin, the founder and C.E.O. “Last year, it was $4.7 million.”

One of Mr. Goldin’s repeat customers is Clement Kwan, the former president of Yoox Net-a-Porter and a founder of Beboe, an upscale line of cannabis vaporizers and edible pastilles that The New York Times has called “the Hermès of Marijuana.”

“Since the pandemic started, my financial portfolio has gone up 50 percent,” Mr. Kwan said from Miami last week. “My collectibles went up by 200.”

Mr. Kwan’s windfall came after learning in 2019 that a documentary about Michael Jordan was going to be released the following summer on Netflix. That led him to buy up sets of Mr. Jordan’s rookie cards at around $30,000 each. He also took a stake in Bleecker Trading, a bespoke sports memorabilia store in the West Village.

In May of 2020, Mr. Kwan sold a Jordan rookie card for nearly $100,000. By January, a particularly in-demand Jordan rookie card sold through Goldin for $738,000.

The renewed interest in Mr. Jordan extends to sneakers.

Last May, Ariana Peters — who, along with her sisters Dakota and Dresden Peters, owns what some believe is the most valuable sneaker collection in the world — had her biggest sale in five years of being in business: a pair of autographed 1985 Air Jordans that fetched $275,000.

In 2019, the sisters sold 572 pairs of sneakers, at prices that began at $500, Ariana Peters said in an interview. In 2020, they sold 879.

Ms. Peters actually sounded somewhat surprised talking about all this, perhaps because she and her sisters only got into the business because their father, a retired real estate developer named Douglas Roy Peters, bought so many pairs of sneakers they were running out of places to put them.

Ms. Peters, who lives in South Florida, now houses the collection in a storage facility that’s been customized to look like the Miami Heat’s basketball court.

Leveraging Nostalgia, From Nintendo to Pokémon

Those unprepared to shell out high sums for vintage collectibles are getting in on the action through recently established mutual funds.

Rally, an Android and iPhone app that sells fractional shares in everything from Rolex GMTs to dinosaur remains, had 100,000 users at the start of the pandemic and oversaw $12 million in inventory. Rob Petrozzo, its chief product officer and co-founder, said in an interview that the company now oversees $30 million of merchandise and has over 200,000 users. According to the company, the average age of a Rally user is 28, and most are male.

The way the app works, investors buy, sell or trade their shares as if they were stocks. New product launches are actually called I.P.O.s.

“The equities space and the cryptocurrency space over the last couple years created really savvy investors who understand the dynamics of the market, so it’s a complement to their Coinbase accounts and their Robinhood accounts,” Mr. Petrozzo said.

One of Mr. Petrozzo’s “investors” is Nicholas Abouzeid, the 24-year-old head of marketing at MainStreet, a 50-person firm that helps start-ups find and claim tax credits and incentives from the government.

On a recent afternoon, Mr. Abouzeid was talking over Zoom from the bedroom of his home in Woodbury, Conn. In his long-sleeved white T-shirt and wood framed glasses, he looked like any number of young white men who might work for Mark Zuckerberg or Josh Kushner. Behind him were shelves of memorabilia — super plastic toys, sealed Nintendo games from the ’90s and collectible Nike Sacai Waffle sneakers.

In the actual stock market, Mr. Abouzeid made last year what he described as “more than what somebody should make in a year,” buying and selling positions in high-growth technology companies such as Slack, Stitch Fix, Shopify and Fastly. “I’m in and out all the time,” he said.

He extracted much of his profits and put them into Pokémon collectibles.

On one level, it’s born of his nostalgia for the game, which he began playing in sixth grade. On another, it’s “an alternative asset class and a way to diversify,” as he put it.

His holy grail item is a first-edition “Booster Box” of Pokémon cards.

Upon its 1999 release, the set cost $110. In January, Heritage Auctions in Dallas sold one for $408,000.

Mr. Abouzeid doesn’t have that kind of money, but in a June 2020 “I.P.O.” from Valley Road, he purchased 125 “shares” of one at a price of $25 each.

They’re now worth $120 each, giving him a profit of around $13,500 (which is at least 300 percent more than he earned from his Slack holdings).

Jackson Moses, a colleague of Mr. Abouzeid’s at MainStreet, invests in biotech stocks and vintage whiskey. But Johnson & Johnson and Jack Daniel’s don’t interest him.

His Merrill Lynch account contains shares of companies like Sarepta Therapeutics, a maker of precision genetic medicines that treat rare neuromuscular and central nervous system diseases. His fridge is filled with rare, vintage Kacho Fugetsu.

“When my parents saw them in my apartment, they got really worried,” he said. “They said, ‘Is there something we need to talk about?’ But I don’t even open them.”

Earlier this month, when rising interest rates sent high-flying tech stocks into a tailspin, Kacho Fugetsu provided what Mr. Moses called “the perfect hedge.”

Of course, he’s aware that the ascent of his whiskey collection also could come to an end, but that at least has an upside. “Then I’ll finally have an excuse to drink it,” he said.