The takeover deal is now worth 1 Drillsearch share for every 5.4 Ambassador shares plus A$0.05 cents extra per share.
Drillsearch recently took a 19% stake in the company, nudging ahead of Magnum.
Magnum’s new offer is a 95% premium on Ambassador’s shares as of 23 May, the final day it traded before entering into a trading halt.
“Magnum Hunter notes the announcement made by Drillsearch yesterday and believes that the revised Magnum Hunter offer is superior to the revised Drillsearch offer,” the company said in a statement.
The company also said it was superior in terms of daily production, market capitalisation and enterprise value.
Late Monday night, Ambassador shareholders which hold a collective interest of about 26.43% chose to accept the Drillsearch offer.
“Magnum Hunter is concerned that such actions have denied Ambassador shareholders the opportunity to participate in the improved Magnum Hunter offer, and have delivered control of Ambassador to Drillsearch to the detriment of Ambassador shareholders.
“Magnum Hunter is concerned that such acceptances have not taken place in an efficient, competitive and informed market and are inconsistent with the actions that would normally be associated with achieving the best possible outcome for Ambassador shareholders.”
The company said it was making an application to the Australian takeover panel.