Simon Property Group insists it is Taubman shareholders who should decide whether to accept the tender offer, which expires Jan. 17. With New York law firm Willkie Farr & Gallagher advising them, Simon Property Group officials have gone to court in Michigan, contending the Taubman family is attempting to exert undue control over the company and prevent a sale.

Advice from Goldman, Sachs & Co. to Taubman Centers included now is not the time to sell, the offer is subject to too many conditions that could derail a deal and a sale could result in antitrust troubles, according to Taubman Centers officials.

"Our collection of upscale regional mall assets cannot be replicated," Taubman adds. "They represent the most productive portfolio of regional malls in the public sector and have always been and will always be highly coveted."

The offer, which was upped from an original bid of $17.50 per share (See: Simon Ups Ante, Taubman Ponders Offer ), continues to represent an all-time high as well as a premium for Taubman Centers stock, which was trading at $16.58 Wednesday afternoon.