Australian Pharmaceutical Industries Limited (ASX:API) and rival Sigma Healthcare Limited (ASX:SIG) are understood to have revived merger talks in recent weeks, suggesting Wesfarmers Limited (ASX:WES) could have a fight on its hands to win over its $687 million takeover target. Wesfarmers' bid equates to $1.38 per share, a 21% premium to the closing share price on July 09, 2021. However, API's shares closed at $1.37 on July 12, 2021.

DataRoom understands that just weeks ago, outgoing Sigma boss Mark Hooper was approached by API over a tie-up that would unlock millions of dollars' worth of synergies. However, some believe Wesfarmers' bid could see a change of tact from Sigma since a more powerful competitor could be created under Wesfarmers' ownership.