Corp. Code, § 704

(a) If shares stand of record in the names of two or more persons, whether fiduciaries, members of a partnership, joint tenants, tenants in common, spouses as community property, tenants by the entirety, voting trustees, persons entitled to vote under a shareholder voting agreement or otherwise, or if two or more persons (including proxyholders) have the same fiduciary relationship respecting the same shares, unless the secretary of the corporation is given written notice to the contrary and is furnished with a copy of the instrument or order appointing them or creating the relationship wherein it is so provided, their acts with respect to voting shall have the following effect:

(1) If only one votes, such act binds all.

(2) If more than one vote, the act of the majority so voting binds all.

(3) If more than one vote, but the vote is evenly split on any particular matter, each faction may vote the securities in question proportionately.

(b) If the instrument so filed or the registration of the shares shows that any such tenancy is held in unequal interests, a majority or even split for the purpose of this section shall be a majority or even split in interest.