american idol logoThe CKX board has taken evasive action to repel a mystery bid. It has approved a measure to protect shareholders from “potentially coercive takeover tactics” after an unnamed third party served notice of a potential bid. CKX won’t say who the mystery bidder is.

The third party indicated it was in talks with founder Robert Sillerman, who has made his own plays for the company. Sillerman resigned as chairman and CEO in May partly to pursue his own bid for the company. CKX said Sillerman is not expected to throw in his lot with this new buyer. But his 21% shareholding, if combined with those sought by the third party, would create the majority stake.

It’s the latest twist in CKX’s courtship by would-be buyers. American Idol creator Simon Fuller made a $600 million bid last month. Fuller and former Barclay Capital banker Roger Jenkins have amassed a $1 billion war chest to fund their CKX buyout. Fuller’s offer trumped a previous $550-560 million offer in March from One Equity Partners, the JP Morgan private equity arm. One Equity Partners had been working with Sillerman and media investor Allen Shapiro.