The star lot in Christie’s Spring Contemporary Art sale will be Andy Warhol’s “Green Car Crash (Green Burning Car I)” (1963), which the auction house hopes will sell for somewhere between $25 million and $35 million. If the painting sells for the high end of the estimate, it will not only be a new record for the artist, but double the previous record auction price of $17 million, set last November for Warhol’s “Mao II” (1972).

The rapid rise in contemporary art prices, which started nine years ago and has accelerated every season since, has many in the art world nervous that their market is beginning to resemble the volatile financial markets. The presence of many hedge-fund managers — the puppet masters of the herky-jerky stock market — among the new breed of art collector has many dealers on edge.

Steven Cohen, the hedge-fund titan whose annual income increased to an estimated $1 billion in 2005 from about $400 million earlier in this decade, is representative of the art world’s worst fears. Since he began collecting in 2000, Mr. Cohen has spent an estimated $700 million on art. Even with a net worth estimated at $3 billion by Forbes, that’s a very large position to hold in one type of asset. Will Mr. Cohen expect the same return on his art that he sees on his other investments? No one knows.

In March, the Baer Faxt, an artindustry newsletter, reported rumors that Mr. Cohen had bought Jeff Koons’s “Balloon Dog” from the artist for $17 million. This not long after the New York Times reported that he privately bought a “Woman” painting by Willem de Kooning from Hollywood mogul and longtime collector David Geffen for $137.5 million. And, yes, it has been reported that Mr. Cohen bought a Warhol privately for $25 million.

The rest of the new collectors, the ones who are not in Mr. Cohen’s league, are still universally recognized as confident, independent minded, and willing to take risks on new and obscure artists.

Traditionally, the art market functioned in a fairly discreet way. Information on sales and prices was limited to begin with, and held by a tightly knit mandarinate. Gallery owners typically exert a lot of pressure to control market forces. Primary dealers, those who represent working artists and sell what comes off their easels, are more like stage mothers than agents. They create buzz and exclusivity, and carefully tend to an artist’s reputation. They also worry a lot about whether their artist will get a shot at stardom — and survive.

To increase the chances, a dealer attempts to place an artist’s work into a prestigious collection or, eventually, a museum. Though the dealer benefits from every sale made, she knows that her artist’s value — not to mention ego — is enhanced by limiting access to the market, with dealers getting to pick and choose who will make the coveted waiting list for an artist in demand. With the most sought after spots tightly controlled, “you have to be more privileged than even having money to get these,” said Sotheby’s Contemporary art specialist, Alex Rotter, said.

Today, however, there is a new market for art driven by a group of collectors who view it as an investment. These collectors are financially sophisticated and obsessed: They drill down for every last bit of information. “Being in the know is a lot of work,” the gallery owner and art adviser, Jack Tilton, said. “You’ve got to put a lot of time in. You go to Chelsea every month — that’s 350 galleries! — you go to every museum show.” But what is a couple of hundred hours of pouring over data points to any self-respecting financial genius?

For these analytically minded collectors, there is much more information today than there was a few years ago. Services like Artnet.comtrack sales, collect price data, and issue reports much the way investment banks cover stocks. With the center of art buying shifting from hard-to-win gallery relationships to the more open atmosphere of art fairs and auction houses, where prices are freely posted and openly discussed, new artists have become like IPOs.

One result has been a new kind of collector who is intensely focused on the work of only a few current artists. “They know everything about Dirk Skreber,” the editor of the Baer Faxt, Josh Baer, said, referring to the somewhat obscure German Liepzigschool painter who made a record price at Christie’s in 2005. “But they can’t spell Sigmar Polke,” Mr. Baer added, referring to the long-established German painter who is a contemporary of Gerhard Richter’s.

Demand from the hedgies is certainly driving prices, but the supply is coming from another place — the collectors who have spotted the top in specific artists and are selling their most sought-after pieces. The recent sale at Christie’s of the Swiss dealer Pierre Huber’s collection caused a great deal of consternation among artists and primary dealers who felt Mr. Huber had repudiated a promise to place the work in museums or allow the primary dealer to resell it to someone who would.

Big sellers who have chosen not to hoard paintings include David Geffen, Charles Saatchi, Peter Brant, New York’s Mugrabi family, and a handful of others who have been collecting since before the current boom began. These sellers made their fortunes in the music, advertising, newspaper pulp, and even garment businesses. In other words, a bunch of old market makers are making out like bandits.

“Nobody liked Warhol at $300,000,” said Alberto Mugrabi, one of the two sons of Jose Mugrabi, who bought a lot at that price. “But they love him at $3 million.”

Mr. Mugrabi is doing more than just selling his holdings. He’s making a market in Warhols. At last season’s evening sale at Sotheby’s Messrs. Mugrabi and Brandt got into a bidding war for Warhol’s “Self-Portrait” (1964). “I’m only helping my collection,” he said. “If I don’t get it, I’m keeping the market healthy. Everyone likes a healthy market.”