Fair Labor Standards Act (FLSA) - Section 531.40
Under the Fair Labor Standards Act (FLSA), the "regular rate" of pay may be more than the minimum wage, but it cannot
be less. Except for certain types of payments that are specified in Section 207(e) of the act, an employee's regular rate
includes all payments made by the employer to, or on behalf of, that employee, assuming that the employee receives no
compensation other than that stated.

Wage deductions:

In most cases, the FLSA does not prohibit deductions from wage payments, but regular rates and overtime pay must be
figured before the deductions are made. In other words, employee deductions and contributions are permissible, but
overtime is calculated on the regular rate before the deductions are made.
FLSA - 510 Regular Rate of Pay