In an analysis of the challenges that gallerists are facing, Marc Spiegler, the global director of the Art Basel fairs, suggested last month that about 80 percent of the artists selling well today would be “basically unsellable” in 20 years.

But that is perfectly fine, Mr. Spiegler wrote in The Art Newspaper, “because collecting contemporary art is about engaging with the zeitgeist.”

It remains to be seen whether such a result will be fine with the thousands of buyers who have been led to believe that contemporary art is also a lucrative investment.

But Mr. Spiegler’s pronouncement, coming at what he characterized as “a starkly transitional moment in the art world,” is a timely reminder of the extent to which collecting is, and always has been, a gamble.

“People buy contemporary art for a range of reasons,” said Guy Jennings, the managing director of the Fine Art Fund Group, an art investment and advisory company in London. “And they aren’t under any illusions that all their artists are going to go up in price.”

“But we have become more financially minded,” he said. “At times like these, buyers will be more cautious and look to artists they think will survive.”

Last week, as the financial markets were buffeted by concerns about a global slowdown, works by hundreds of postwar and contemporary artists were offered at London’s annual February auctions and exhibitions. With the economic outlook seeming increasingly bearish, which names should buyers back in the face of a possible downturn?

The results in London offered some clues. At Sotheby’s contemporary sale on Wednesday night, individual prices far above presale estimates created a sense that the market was still booming. Examples were the 16.1 million pounds, or about $23.2 million, given by a telephone bidder for Lucian Freud’s 1961 portrait of his pregnant 17-year-old lover, Bernadine Coverley, valued at ￡7 million to ￡10 million, and the ￡3.1 million for “The Sunflowers in 1937,” a colossal 2014 faux van Gogh painting by the highly regarded Adrian Ghenie.

Mr. Ghenie’s reputation was enhanced last year when he represented his native Romania at the Venice Biennale. Acquired by its seller less than two years ago from Galerie Judin in Berlin, “The Sunflowers” compellingly combines references to Nazi-era “degenerate art” with a monumental wall presence. Ten bidders pushed the price to more than five times the estimate of ￡400,000 to ￡600,000, reflecting the lengthy waiting list for Mr. Ghenie’s small output.

Elsewhere, it seemed like wealthy buyers — and sellers — were keeping one eye on the high-end art and another on the financial market indexes.

Overall numbers at Sotheby’s were down sharply. The 55-lot sale brought in a total of ￡69.5 million, 44 percent lower than the ￡123.5 million achieved at the company’s equivalent contemporary auction last February. Twenty-two percent of the lots were left unsold.

Proceeds this year were dented by the 11th-hour withdrawal of a Gerhard Richter abstract valued at ￡14 million to ￡20 million. Neither the auction house nor a third party had been willing to risk guaranteeing the sale of such a high-value work in the current environment.

“Rightly or wrongly, the capital markets determine confidence levels,” said Andrew Terner, a private dealer based in New York. “It’s the psychology of the moment. The timing has to be right.”

In midday New York trading on Friday, , Sotheby’s stock price was at $20.07 after having dropped 17.5 percent on Thursday.

Year-on-year results at Christie’s on Thursday evening were even more bearish. The ￡58.1 million total achieved from its contemporary sale was down 50 percent from the February 2015 auction.

But if, in general terms, buying museum-endorsed art from the last 100 years — like a Richter or a Ghenie — still remains almost the only game in town for the wealthiest art collectors, what about the more speculative market for artists with emerging reputations?

On Wednesday, Phillips held a day sale of 178 lots of 20th-century and contemporary art, and conspicuous by their absence were the “process-based” abstract paintings that had been the subject of lucrative resales at Phillips in the boom year of 2014. Once-hot names like Lucien Smith, Mark Flood and David Ostrowski were not in the catalog, and a small 2014 abstract by Dan Rees, “Gravelmaster,” estimated at ￡6,000 to ￡8,000, did not attract a buyer.

This kind of abstraction was looking “basically unsellable,” leaving three bidders to contest instead a safer Rudolf Stingel mock wallpaper painting from 2005 — in highly commercial gold enamel — to a top price of ￡386,500, just above the high estimate. Most prices at Phillips were at the low estimates, but 72 percent of the works did find buyers.

Yet at the galleries that supply these auctions, collectors were continuing to pay significant sums for market-fresh works by artists who they think might still be in demand in the 2030s, or at least at the end of this decade.

The “Ecriture” paintings of Park Seo-bo, a pioneer of the recently re-evaluated Korean monochrome movement called Dansaekhwa, are on show through March 12 at White Cube Mason’s Yard in London. Fourteen of these contemplative calligraphic abstracts, ranging in date from 1967 to 1981, were released for sale by the artist, who is now 84, and all have sold for between $400,000 and $650,000.

Nate Lowman, 37, is a New York artist whose 2011 “Marilyn” paintings, which cannily combine echoes of de Kooning and Warhol, resold for as much as $870,000 at auction in 2014. On Tuesday evening, the London gallery of Massimo de Carlo presented some 15 black-and-white paintings by Mr. Lowman derived from photographs of the elaborately patterned ceiling of his studio. Priced at $120,000 to $250,000, four of these paintings quickly found buyers, with several others on hold.

Something quite different was on offer at Condo, a new collaborative exhibition by 24 emerging galleries spread across eight spaces in London.

The event, which began Jan. 16 and ends on Saturday, was conceived by Vanessa Carlos, a co-founder of the London gallery Carlos/Ishikawa, as a cost-effective alternative to fairs. Dealers from a range of countries paid just ￡600 to be guest exhibitors. Unlike at a fair, entrance for visitors was free. Prices for work were generally in four figures.

“The habit of collectors going to galleries has diminished because of art fairs,” said Tom Cole, a co-director of The Sunday Painter, a gallery in Peckham, in southeast London. “Trying to find alternative models to show a program and get a name out there has become more and more important.”

Mr. Cole said that about 500 people visited his gallery on the first Saturday of Condo, compared with the 10 or 20 who might attend the Saturday of a typical exhibition. Among his sales was “Not Too Clever Emoticon,” a 2013 sculpture made from a glass-panel heater by the gallery’s artist Rob Chavasse, priced at ￡4,000.

Largely free from the commercial pressures of an art fair, Condo displayed works that could also be refreshingly confrontational. Arcadia Missa, also in Peckham, showed a joint multimedia installation combining works by the American artist A.L. Steiner, of the collective Chicks on Speed, and the British feminist artist Phoebe Collings-James. The latter’s 2016 sculpture “Oh My Darling, Clementine,” consisting of two glazed ceramic clementines in a plastic netting bag, was sold for a price between ￡1,000 and ￡2,000.

At this price level, collectors can happily engage with the zeitgeist, without worrying too much if the work they bought will be salable a few decades down the road.