Example. An individual, H, his wife, W, his son, S, and his grandson (S's son), G, own the 100 outstanding shares of stock of a corporation, each owning 25 shares. H, W, and S are each considered as owning 100 shares. G is considered as owning only 50 shares, that is, his own and his father's.
26 C.F.R. §1.318-2