(a) For purposes of this subchapter, a person, other than the issuing public corporation or a wholly owned subsidiary of the issuing public corporation, is an affiliated shareholder if the person:
(1) is the beneficial owner of 20 percent or more of the outstanding voting shares of the issuing public corporation; or
(2) during the preceding three-year period, was the beneficial owner of 20 percent or more of the outstanding voting shares of the issuing public corporation.
(b) To determine whether a person is an affiliated shareholder, the number of voting shares of the issuing public corporation considered outstanding includes shares considered beneficially owned by that person under Section 21.603, but does not include other unissued voting shares of the issuing public corporation that may be issuable under an agreement, arrangement, or understanding, or on exercise of conversion rights, warrants, or options.