When is there an ultra vires act on the part of [a] the corporation; [b] the board of directors; and [c] the corporate officers?

There is an ultra vires act on the part of the corporation when it performs acts which are not provide in its express, implied or incidental powers. There is ultra vires act on the part of the board of directors when it performs acts which are not delegated to it by the articles of incorporation or the bylaws. There is ultra vires act on the part of the corporate officers when they perform acts which are not authorized by the bya laws and the articles of incorporation or not delegated to them by the board of directors. (2009 Bar Question)

What are the effects of an ultra vires act?

Ultra vires acts entered into by the board of directors binds the corporation and the courts will not interfere unless terms are oppressive and unconscionable. (Gamboa vs. Victoriano, G.R. No. L-­‐43324. May 5, 1979)