To limit the authority of States to tax certain income of employees for employment duties performed in other States.

SECTION 1. SHORT TITLE.

    This Act may be cited as the ``Mobile Workforce State Income Tax 
Fairness and Simplification Act''.

SEC. 2. LIMITATIONS ON STATE WITHHOLDING AND TAXATION OF EMPLOYEE 
              INCOME.

    (a) In General.--No part of the wages or other remuneration earned 
by an employee who performs employment duties in more than one State 
shall be subject to income tax in any State other than--
            (1) the State of the employee's residence; and
            (2) the State within which the employee is present and 
        performing employment duties for more than 30 days during the 
        calendar year in which the income is earned.
    (b) Wages or Other Remuneration.--Wages or other remuneration 
earned in any calendar year are not subject to State income tax 
withholding and reporting unless the employee is subject to income tax 
under subsection (a). Income tax withholding and reporting under 
subsection (a)(2) shall apply to wages or other remuneration earned as 
of the commencement date of duties in the State during the calendar 
year.
    (c) Operating Rules.--For purposes of determining an employer's 
State income tax withholding and information return obligations--
            (1) an employer may rely on an employee's determination of 
        the time expected to be spent by such employee in the States in 
        which the employee will perform duties absent--
                    (A) actual knowledge of fraud by the employee in 
                making the estimate; or
                    (B) collusion between the employer and the employee 
                to evade tax;
            (2) if records are maintained by an employer recording the 
        location of an employee for other business purposes, such 
        records shall not preclude an employer's ability to rely on an 
        employee's determination as set forth in paragraph (1); and
            (3) notwithstanding paragraph (2), if an employer, at its 
        sole discretion, maintains a time and attendance system which 
        tracks where the employee performs duties on a daily basis, 
        data from the time and attendance system shall be used instead 
        of the employee's determination as set forth in paragraph (1).
    (d) Definitions and Special Rules.--For purposes of this Act:
            (1) Day.--
                    (A) An employee will be considered present and 
                performing employment duties within a State for a day 
                if the employee performs the preponderance of the 
                employee's employment duties within such State for such 
                day.
                    (B) Notwithstanding subsection (d)(1)(A), if an 
                employee performs material employment duties in a 
                resident state and one nonresident state during one 
                day, such employee will be considered to have performed 
                the preponderance of the employee's employment duties 
                in the nonresident state for such day.
                    (C) For purposes of subsection (d)(1), the portion 
                of the day the employee is in transit shall not apply 
                in determining the location of an employee's 
                performance of employment duties.
            (2) Employee.--The term ``employee'' shall be defined by 
        the State in which the duties are performed, except that the 
        term ``employee'' shall not include a professional athlete, 
        professional entertainer, or certain public figures.
            (3) Professional athlete.--The term ``professional 
        athlete'' means a person who performs services in a 
        professional athletic event, provided that the wages or other 
        remuneration are paid to such person for performing services in 
        his or her capacity as a professional athlete.
            (4) Professional entertainer.--The term ``professional 
        entertainer'' means a person who performs services in the 
        professional performing arts for wages or other remuneration on 
        a per-event basis, provided that the wages or other 
        remuneration are paid to such person for performing services in 
        his or her capacity as a professional entertainer.
            (5) Certain public figures.--The term ``certain public 
        figures'' means persons of prominence who perform services for 
        wages or other remuneration on a per-event basis, provided that 
        the wages or other remuneration are paid to such person for 
        services provided at a discrete event in the form of a speech, 
        similar presentation or personal appearance.
            (6) Employer.--The term ``employer'' has the meaning given 
        such term in section 3401(d) of the Internal Revenue Code of 
        1986 (26 U.S.C. 3401(d)) or shall be defined by the State in 
        which the duties are performed.
            (7) State.--The term ``State'' means each of the several 
        States of the United States.
            (8) Time and attendance system.--The term ``time and 
        attendance system'' means a system where the employee is 
        required on a contemporaneous basis to record his work location 
        for every day worked outside of the state in which the 
        employee's duties are primarily preformed and the employer uses 
        this data to allocate the employee's wages between all taxing 
        jurisdictions in which the employee performs duties.
            (9) Wages or other remuneration.--The term ``wages or other 
        remuneration'' shall be defined by the State in which the 
        employment duties are performed.

SEC. 3. EFFECTIVE DATE.

    This Act shall be effective on January 1, 2011.

Summary: Mobile Workforce State Income Tax Fairness and Simplification Act - Limits state taxation of the wages or other remuneration of any employee who performs duties in more than one state to: (1) the state of the employee's residence; and (2) the state in which the employee is present and performing employment duties for more than 30 days. Exempts from the definition of "employee" for purposes of this Act a professional athlete or entertainer or certain public figures.