Shares of Healius slumped as much as 9.2% to A$1.475 and were set for their worst session since Nov 22 if current losses held, while those of Australian Clinical Labs fell more than 2%.
Australian Clinical Labs noted a 45% slide in Healius' share price since the announcement of the deal on March 20 and that its board was concerned for the latter's half-year results.
"The ACL Board is concerned based on the 1H guidance that Healius is at risk of a significant statutory NPAT (net profit after tax) loss in 1H FY24," the company said in a statement.
Healius in November forecast its earnings before interest and tax for the first half to be between A$14 million and A$17 million.
Earlier in the day, the country's competition watchdog decided to oppose the acquisition, as it is likely to lessen competition in the domestic pathology services market.
The Australian Competition and Consumer Commission (ACCC) said it was unlikely that a new existing provider could enter and expand to address the loss of competition arising from the acquisition.
"The company has noted the ACCC's clear decision in the matter," a Healius spokesman said.
($1 = 1.4932 Australian dollars)
(Reporting by Archishma Iyer in Bengaluru; Editing by Shinjini Ganguli and Subhranshu Sahu)
