British gas utility titan BG Group PLC (OTC ADR: BRGYY) went hostile in its takeover bid for Australia’s Origin Energy Ltd. (PINK: OGFGF), Australia’s largest coal-seam-gas producer, taking its offer of A$15.50 per share, which values the company at $13.1 billion (A$13.8 billion dollars), directly to shareholders.

BG Group originally offered A$14.70 to Origin’s board in April, at the time a 40% premium. That spurred further discussions and Origin recommended that BG Group up its bid to A$15.50 per share, a 48% premium.

Origin then backed out of the deal in May, forcing BG Group to make a 15-page assertion that the price is right and the time is now. Buried in those pages are not-so-subtle suggestions that Origin hadn’t been entirely forthright about its operations and pending market risks. 

“We believe Origin shareholders have limited visibility of the risks inherent in Origin’s current reserves position and Liquefied Natural Gas (LNG) joint venture alternatives,” BG Group Chief Executive Frank Chapman said in the statement.

“Today, Origin does not have sufficient coal seam gas (CSG) reserves for a LNG joint venture: there are third-party contractual rights over a large number of Origin’s tenements that have not been adequately explained; and Origin’s domestic market requirements from CSG exceed the company’s currently available proven reserves.” 

Origin quickly moved to blunt the proposal, issuing a statement advising shareholders to “take no action in relation to the offer or any documents they receive from BG at this stage.”

With the purchase of Origin, BG Group would gain more traction in the Australia-Asia market. Origin has substantial reserves of coal-seam gas, a type of natural gas that is attached to and extracted from coal beds.

In a conference call, Chapman said that BG had no plans to raise its offer, a wise move according to Citigroup Inc. (C) analyst David Thomas.

“A significantly higher offer would not have sat well with BG’s shareholders, especially in view of the counterarguments made after the Origin Energy management rejection, most notably regarding the scale of the coal-seam-methane resource potential,” Thomas told MarketWatch.

If Origin shareholders accept the offer, it would be the second-largest foreign acquisition in Australia, behind the $14.2 billion takeover of Rinker Group by Cemex SAB de CV (ADR: CX), MarketWatch reported.