In a statement to the market, Nexus said it had acquired 10.91% of Anzon’s issued capital, gained via a $45.3 million on-market purchase and an off-market exchange of shares.

Nexus' acquisition pre-empts a formal process by the company for potential bidders, rumoured to include Origin Energy, Santos, Australian Worldwide Exploration and Arc Energy.

The on-market purchase saw Nexus pay just under $1.69 for each of the 26.8 million shares in Anzon, which at 4pm (EST) was trading at $1.77 per share.

Nexus acquired a further 13.6 million AZA shares from Viking Shipping, in exchange for 14.96 million of its own shares.

Viking is Nexus' major shareholder, with about 18%, and is the major backer of its Crux project, in the Browse Basin.

The move is a 180-degree turnaround from only 18 months ago, when Nexus was the subject of a $170 million hostile takeover bid from Anzon.

The punters backed Nexus, and Anzon only secured about 17% of NXS stock by the close of the offer.

Then last week, Anzon announced it was up for sale, opening its data room to allow a shortlist of would-be buyers to conduct formal due diligence ahead of a potential sale.

Analysts and media identified Nexus as a potential suitor, saying a takeover would help the company remove Anzon as a shareholder and make itself more appealing as a target.

Synergies between the Basker-Manta-Gummy and Longtom gas projects, both in the Gippsland Basin, as well as a desire to acquire existing production have also been identified as reasons why Nexus would want to acquire Anzon.

According to a report in today's Australian Financial Review, Nexus and Anzon had been having friendly takeover discussions, and when these broke down Anzon initiated the opening of its data room.

Anzon Energy, which is listed on London's Alternative Investment Market and owns 53% of Anzon Australia, will play the most critical role in any acquisition of the company.