The suit alleges that the board took steps to dig into their positions at shareholders' expense, Courthouse News reports. Tenet paid Bush $245,000 for sitting on the board in 2009. In December, CHS offered to buy Tenet's shares in a deal valued at $6 per share, 40 percent more than Tenet's price on the day of the announcement, the lawsuit says. Tenet rejected the offer "without any negotiation or due diligence," according to the complaint.