(ShareCast News) - Qatar Airways took advantage of the current weakness in IAG´s shares to increase what it described as a "purely financial" investment.The state-owned carrier increased its holdings from 15.67% to 20.01%, reports said.Qatar Airways also said the acquistion was a reflection of the strong commercial and strategic ties between both carriers.Nonetheless, it had no intention of further increasing its stake unless conditions changed materially."The recent market valuation of one of the world's leading airline groups has provided what we believe is an attractive opportunity to increase our shareholding in IAG," Qatar Airways chief executive officer Akbar Al Baker reportedly said in a statement.Monday´s move followed the Middle Easter airline´s decicion in July to buy 10% of Chile´s LATAM Airlines together with a 49.0% stake in Italy´s Meridana Fly.