Despite assurances it has no plans to take over Ubisoft, French media conglomerate Vivendi has increased the amount of shares it owns in the Assassin's Creed, Far Cry, and The Division publisher.

In October 2015, Vivendi purchased a 6.6 percent stake in Ubisoft, before raising it to 10 percent in February 2016, and then 18 percent in April, 2016. Bloomberg reports Vivendi now holds 20.1 percent stake in Ubisoft, and is considering acquiring more shares.

Vivendi chief executive Vincent Bollore has said he aims to develop a "fruitful cooperation" with Ubisoft, and added that he isn't considering an offer to purchase some or all of the remaining shares, thus taking control of the company, for the next six months.

Vivendi's increase in stake ownership has resulted in a rise in Ubisoft shares. The publisher now has a market value of $4.2 billion on France's SBF120 Index. Vivendi's market value, meanwhile, also increased by 3.4 percent.

In April, Vivendi gained majority control of mobile publisher Gameloft, which was run by Michel Guillemot, brother of Ubisoft chief executive Yves Guillemot. Following the acquisition, the Guillemot family said it will sell its remaining control to Vivendi.

Analysts believe that Vivendi's acquisition of Gameloft is part of a larger plan to buy Ubisoft. It is believed the Guillemots are currently working with financial advisers to build a defence plan against a potential takeover attempt from Vivendi.