J O Hambro Capital Management, the UK investment manager, has launched a "put up or shut up" share tender offer for Quarto, a book publisher, in a move that sidesteps normal Takeover Panel rules.

The tender offer of 132.5p a share for nearly 25% of Quarto follows the collapse of talks with Quarto earlier this month. On behalf of its clients J O Hambro already holds over 26% of the listed company so under normal circumstances Christopher Mills, chief investment officer at J O Hambro, would have to bid for the balance of the equity once the tender took him up to 30%.