Ubisoft CEO Yves Guillemot, in an investor call with Joystiq, explained that Ubisoft "doesn't have a huge investment" in the Wii U.
It's a curious statement given Ubisoft's love affair with the Wii and all things Nintendo, as well as their upcoming titles for Wii U, Rayman Legends and ZombiU.
Guillemot, however, pointed out that Ubisoft wasn't necessarily developing new games for the Wii U but ports of what they've already released on current consoles. And Rayman Legends and ZombiU, despite being original titles, "are much smaller of cost" than making original titles for Xbox 360 and PS3:
Because, as we've always said when there is such an innovation, the need is not to have big production value but to concentrate on the innovation. This is what we are trying on Rayman and ZombiU.
Even if Ubisoft says they aren't heavily invested with the Wii U, they will likely still be one of the firmer third-party supporters of the console.
[Source]