30 Del. C. § 1151

(a) General. — Every employer maintaining an office, or transacting business, within this State and making payment of any wages or other remuneration taxable under this chapter to a resident or nonresident individual whose wages or other remuneration are subject to withholding under the Internal Revenue Code shall deduct and withhold from such wages for each payroll period a tax computed in such manner as to result, insofar as practicable, in withholding from the employee’s wages during each calendar year an amount substantially equivalent to the tax reasonably estimated to be due from the employee under this chapter with respect to the amount of such wages included in the taxable income during the calendar year. The method of determining the amount to be withheld shall be prescribed by rules or forms of the State Tax Department. The State Tax Department is authorized to promulgate withholding tables for this purpose.

(b) Withholding exemptions. — For purposes of this section, an employee shall be entitled to the same number of withholding exemptions as the number of withholding exemptions to which the employee is entitled for federal income tax withholding purposes. An employer may rely upon the number of federal withholding exemptions claimed by the employee.

(c) Withholding agreements. — The State Tax Commissioner may enter into agreements with the tax departments of other states (which require income tax to be withheld from the payment of wages or other remuneration and salaries) so as to govern the amounts to be withheld from the wages and salaries of residents of such states under this chapter. Such agreements may provide for recognition of anticipated tax credits in determining the amounts to be withheld and, under rules prescribed by the State Tax Commissioner, may relieve employers in this State from withholding income tax on wages or other remuneration and salaries paid to nonresident employees. The agreements authorized by this subsection are subject to the condition that the tax department of such other states grant similar treatment to residents of this State.