Rev. & Tax. Code, § 18537

(a) For taxable years beginning on or after January 1, 2021, in lieu of nonresident aliens filing a return pursuant to Section 18501, the Franchise Tax Board shall provide for the filing of a group return by a taxpayer, or an entity authorized by the taxpayer to file on its behalf, for one or more electing nonresident aliens who receive taxable income as computed under paragraph (1) of subdivision (i) of Section 17041 from that taxpayer for services that take place in this state.

(b) For a nonresident alien electing to file in a group return pursuant to subdivision (a), the tax rate or rates applicable to each nonresident’s taxable income for services performed in this state for that taxpayer shall consist of the highest marginal rate or rates provided for by Part 10 (commencing with Section 17001) plus, in the case of any electing nonresident alien included on the group return who would be subject to Section 17043 when filing individually, an additional tax rate of 1 percent, and no deductions or credits shall be allowed, except credits allowed under Section 19002.

(c) The taxpayer, or an entity authorized by the taxpayer to file on its behalf, as the agent for the electing nonresident aliens, shall make the payments of tax, additions to tax, interest, and penalties otherwise required to be paid by, or imposed on, the electing nonresident aliens.

(d) Pursuant to Section 18624, the Franchise Tax Board shall not require a nonresident alien who is not eligible for or has not been issued a federal social security number (SSN) or a federal individual taxpayer identification number (ITIN) to provide a SSN or ITIN in order to file in a group return under this section. If the nonresident alien subsequently becomes eligible for and is issued a SSN or ITIN, the Franchise Tax Board may require the nonresident alien to provide a letter or other form documenting the nonresident alien’s SSN or ITIN.

(e) The Franchise Tax Board may adjust the income of an electing nonresident alien taxpayer included in a group return filed under this section to properly reflect the income under Part 10 (commencing with Section 17001).

(f) (1) The Franchise Tax Board may adopt regulations as necessary or appropriate to carry out the purposes of this section.

(2) Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code shall not apply to any standard, criterion, procedure, determination, rule, notice, or guideline established or issued by the Franchise Tax Board.

(g) For purposes of this section, “nonresident alien” shall have the same meaning as described in subdivision (f) of Section 18624.