Volvo increased its voting stake by 2.1% last week. In January, Volvo bought 13.5% of Scania and said it wanted to buy the rest.
Scania and Investor AB, Scania's largest shareholder with 46%, have said they believe the company can prosper on its own. They have also said they are interested in selling the company but not to Volvo, and that Volvo's ownership has scared away other potential buyers.
Volvo, the world's second-largest truck maker, is flush with cash after selling its car unit to Ford Motor Co. for $6.5 billion. The company has said it wants to focus on building trucks and buses.