Horizon Oil (ASX:HZN) posted proved and probable (2P) reserves of 13.6 million barrels of oil-equivalent (MMboe) as at June 30, jumping 51% from 9 MMboe as of June 30, 2025, according to a Monday filing with the Australian bourse.

It attributed the increase to the acquisition of indirect interests in Thailand through MH Energy Thailand, and in Australia, New Zealand, and Indonesia through Cue Energy Resources.

Its net 2C contingent resources increased 61% to 19.8 MMboe from 12.3 MMboe.

The company's total net production jumped to 2.1 MMboe from 1.6 MMboe last year, the filing said. The contribution from Thailand offset the natural decline in China.