Back in December of 2004 it was leaked that EA was to buy a 20% share of Ubisoft. That deal eventually went through.

Today, we have word that EA has upped their piece of Ubisoft to nearly 25% of the voting shares and now own 15.37% of Ubi's capital.
What does that mean? I don't think much. I really don't think that EA wants to take over Ubi. I think they're happy owning a good chunk of them and letting Ubi do what they do best: make good original games (as opposed to the sequel-happy EA).
I also think that EA is smart enough to know that if they took over Ubi, Ubi would lose a good deal of their luster. You want to keep a gem shiny, know what I'm sayin'?
Read the Forbes Article