“Nine!” called out the man in the front row of Sotheby’s last night. He meant $9 million. Suddenly, there was a frantic whisper, then an even more frantic search began among a phalanx of black-tie-clad Sotheby’s employees. The celebrity offering to bid eight figures (once commission is added in) didn’t have an auction catalog. Less than two minutes later, designer Valentino Garavani was handed one. But by then he had been outbid—as he was throughout the evening.

“I didn’t get anything,” he said regretfully of a sale that, by any measure, went through the roof.

Sotheby's raised $316 million at its fall sale of contemporary art, its highest auction total ever. A robust 91 percent, or 65 of 71 lots, sold. Indicating fervid demand at the top end of the art market, 15 artworks sold for more than $5 million each, up from six in a similar spate of spring auctions. The results neatly put an end to widespread fears that woes infecting the mortgage market and investment banks would put a dent in spending on art.

Moreover, Garavani's loud and impassioned bidding was emblematic of perhaps the auction season’s biggest trend: vivid and visible support by longtime players.

Veteran dealers and collectors descended on New York this week, in the face of concerns that the bubbly market would weaken, sending prices for their belongings south. Eli Broad and François Pinault were spotted in the city's Chelsea district looking at David Zwirner's artists. Michael Ovitz attended both contemporary-art sales. Real estate developer (and Sotheby’s landlord) Aby Rosen bid for a Jeff Koons. Alfred Taubman took second row at Sotheby’s, the auction house he used to own. Big-name sellers and buyers included Happy Rockefeller, Adam Lindemann, jeweler Laurence Graff, members of the Picasso and Pissarro families, and actor Hugh Grant. And also attending were celebrities Gina Gershon, Liz Hurley, and Sarah Jessica Parker.

Despite the star wattage, it was dealers who supported this market by paying the top prices, either on behalf of clients or to support their artists. This bidding pattern broke with that of recent years, which saw top prices paid by anonymous telephone bidders. Whether it was Sotheby’s or the dealers who decided to move bidding by those buyers into the salesroom and off the phones is unclear. (In the past, people in the room sometimes placed their bids by cell phone.) But art dealers Larry Gagosian, Philippe Segalot, and Robert Mnuchin, and dealer and collector Alberto Mugrabi did some of the most visible bidding and buying during this two-week auction season, which concludes tonight at boutique auctioneer Phillips de Pury & Co.

Dealer Gagosian nodded, curtly but with a smile, throughout the long bidding war for Jeff Koons' Hanging Heart (Magenta/Gold). Conceived in 1994 but just finished last year, this work is a huge, bright-pink stainless-steel sculpture of a giant heart suspended from a golden metal ribbon. He bid up the artist (whom he represents) to $21 million, or $23.6 million with the commission, setting a record for a living artist at auction. (Damien Hirst’s diamond-encrusted skull, For the Love of God, sold for a reported—but disputed—$100 million in August to an investment group that included the artist and his dealer.) The estimate was $15 million to $20 million.