1. (a) A banking corporation or bank holding company which is not a taxpayer cannot be included in a combined return under section 21-2.2 of this Subpart unless it is part of a unitary business with the other corporations in the group (see section 21-2.3[b][1] of this Subpart) and the Tax Commission determines that the inclusion of such corporation is necessary in order to properly reflect the tax liability of one or more banking corporations or bank holding companies included in the group because of:

   1. (1) intercorporate transactions (see section 21-2.3[b] [3] of this Subpart); or
   2. (2) some agreement, understanding, arrangement or transaction existing between the taxpayer and any other combinable corporation, whereby the activity, business, income or assets of the taxpayer within New York State is improperly or inaccurately reflected (see section 21-2.3[b][4] of this Subpart).
2. (b) A corporation which has properly elected to be taxable under article 9-A of the Tax Law for a taxable year in accordance with the provisions of section 16-2.5(j)(3) of this Title cannot be included in a combined return for that taxable year.
3. (c) A banking corporation whose net worth ratio determined on a separate basis is less than five percent and whose total assets are comprised of 33 percent or more of mortgages will not be included in a combined return for those taxable years for which its tax is determined on a separate basis pursuant to section 18-5.1(b) or (c) of this Title.

Tax Law, § 1462(f)