A sealed-bid auction to sell the 25,000-square-foot-mansion once owned by Conseco Inc. co-founder Stephen Hilbert has attracted a half-dozen potential buyers.

Prudential Indiana agent Greg Cooper, who is co-listing the palatial property, said it could take up to a week to announce a successful bidder.

Carmel-based Conseco, since renamed CNO Financial Group Inc., has been trying to unload the mansion—which it gained control of during a court battle over loans Hilbert took out to buy Conseco stock—for five years. It went on the market with a $20 million asking price, and more recently was listed at $9.9 million.

Cooper declined to elaborate on details of the offers, only saying that “we’ve had multiple bids over a wide range of prices.” But he acknowledged that most were submitted by local bidders.

“They’re more centrally located than you might think,” he said. “It’s very much become a local process, but not exclusively.”

Aspiring owners of the estate had until 11:59 p.m. on Friday to submit a bid. But the bid terms, at www.indianamansion.com, note that the seller “reserves the right to accept a bid prior to or after the bid submission deadline.”

Bids called for $100,000 in so-called “earnest money” to be submitted. And the high bidder whose offer is accepted must deliver no less than 10 percent of the total bid within one business day.

Selecting a bidder will take longer than envisioned because many of them attached contingencies, which included financing and property-closing issues, to the uniform offer sheet they were provided, Cooper said.

“It’s a complex property, and it’s a complex set of circumstances,” he said. “It’s going to take awhile to find the right fit.”

The mansion at 1143 W. 116th St. is being sold “as is,” although CNO Financial has been paying to maintain the property. The company announced its plans in July to conduct a sealed-bid auction.

Cooper previously said the mansion has drawn interest from potential buyers such as race car teams, which often wine and dine their sponsors.

The estate includes a 15,000-square-foot “sports palace,” catering facilities, a guest house and its own power plant.