Healius’ largest shareholders, Perpetual and John Wylie’s Tanarra Capital, squashed Australian Clinical Laboratories’ audacious hostile takeover bid for its much larger rival by declining to support the deal.

Perpetual, which owns 12.5 per cent of Healius making it the target’s No.1 shareholder, and Tanarra Capital, which owns 8.7 per cent, spoiled the ambitions of the smaller ACL, which lobbed an off-market bid requiring the consent of 90 per cent of shareholders.