A leading alternative asset manager has lobbed an $18.4 billion tentative takeover offer for Origin Energy.

Brookfield Asset Management and an LNG company have floated a figure of $9 a share, a 54.9 per cent premium on Wednesday’s closing price of $5.81.

At 10.45am AEDT on Thursday, Origin shares had soared 32.9 per cent to $7.73.

Origin’s board said it had entered into an exclusivity and confidentiality agreement to let the consortium conduct due diligence, expected to finish within eight weeks.

Should a binding offer of $9 per share materialise, the board intends to unanimously recommend shareholders accept it.

“While the due diligence process advances, we will remain focused on the successful execution of our strategy,” said Origin Energy chairman Scott Perkins.

Should the takeover proceed, the consortium intends that Brookfield – one of the world’s biggest alternative investment management companies, with $80 billion invested in Australia – would acquire Origin’s energy markets business.

“Brookfield has the global renewable power expertise and access to capital to support Origin’s transition strategy,” said Brookfield’s Asia Pacific chief executive, Stewart Upson.

“Our business plan includes additional investment of $A20 billion by 2030 to build the required renewable capacity and storage and position Origin as Australia’s leading ‘greentailer’.”

MidOcean Energy, an LNG company created and managed by private equity firm EIG, would take over Origin’s integrated gas business, which includes gas fields and a share of the Australia Pacific LNG joint venture export project in Queensland.

MidOcean Energy last month agreed to acquire stakes in four integrated LNG projects in Australia from Tokyo Gas for $2.15 billion.

Chief executive De la Rey Venter said the firm had been actively seeking to invest in high-quality projects in the Asia-Pacific region.

“Origin’s integrated gas business – which would build on MidOcean’s existing investment in Australia – will help enable broader decarbonisation efforts in the region by supplying critical natural gas and LNG to the domestic and global markets for decades to come,” he said.

– AAP