SARASOTA — Chad Roffers, chief executive of Sky Sotheby's International Realty, has spun off the company's auction division to form a new business.

The new company, Concierge Auctions, has a bold -- if somewhat risky -- premise: to sell every property involved in its auctions.

How is that possible?

Laura Brady, a Sky agent who had been closely involved in the company's recent auctions and has now left to take the helm at Concierge, said managers have come up with a novel way of organizing the auctions -- each property will either be sold absolute (where any bid is accepted), or it will be subject to a "guaranteed minimum."

That guaranteed minimum will be a price agreed to by Concierge and the seller before the auction, based on what the company believes is the correct market value for the home. The calculations will be based on a proprietary computer pricing model that the company has developed.

On auction day, if a bidder surpasses the minimum, he or she will, of course, get the property. But if nobody reaches the minimum -- and this is essentially the revolutionary part -- the auction company itself will make the purchase.

"If it doesn't sell during the auction, we will buy the property at that number," Roffers said. "Every seller is going to walk away happy."

Concierge Auctions, which has opened a downtown office at 1517 State St., is separate from Sky and will not employ the Sotheby's moniker. However, Roffers himself owns part of the new venture, which he said he invested in with his own money.

"I have an ownership stake in the company," Roffers said, though he declined Wednesday to specify how much or to identify his partners.

The new company will aim to become a full-service auction operation catering to the luxury home market in Sarasota and in other high-end markets nationwide. Its first auction is planned for August, and will include a yet-undetermined number of Sarasota and Manatee County properties.

"There's been something of a discrepancy between the way other fine things are auctioned off and the way real estate has been," said Brady, who would like to see real estate auctions achieve the same level of panache as auctions for works of art or luxury cars.

"A lot of it comes down to providing a level of service the buyers and sellers want and expect," Brady said. "That, and the post-experience of getting to closing is very important."

Roffers and Brady both said they took lessons from Sky's previous auctions, where properties with a reserve did not fare as well. Many properties remained unsold.

Sky's most recent auction in April was particularly noticeable, as 35 out of 49 properties on the auction block received bids on auction day, totaling about $35 million, but most of them did not lead to actual sales.

In the end, only nine closings resulted from the April event, including one -- a 10,000-square-foot house at 4067 Shell Road on Siesta Key -- that sold before the auction for $8 million. Including that sale, the total closings from the April event ring in at about $13 million. Without it, the closings were about $5 million.

But Roffers said he still considered the April auction a success, and said the event was profitable for Sky. He said he sees the auction business continuing to be profitable going forward, which is why he is starting the separate auction company.

"I think this is a very good business to be in," he said.

While many in the real estate community have said auctions may go by the wayside when the market recovers, Brady said she does not concur with that sentiment.

"I disagree auctions will only succeed in markets that aren't performing," she said. "I think there is a place for luxury auctions in healthy markets as well. I wouldn't be doing this otherwise."