Wagering giant Tabcorp is trading at its lowest level in more than a decade. So what on earth could have induced its chairman to sell at what appears to be the bottom, despite a stated intention to buy more shares in the near future?

Earlier this month, Paula Dwyer dumped 120,834 shares — about half her holdings — at $2.53 a pop, but immediately purchased back a third of what she'd divested — 45,835 shares at $2.51 each — through another vehicle.