A payment made, or benefit furnished, to or for the benefit of an employee in a taxable year beginning after December 31, 1978, does not constitute wages and hence is not subject to withholding if, at the time of such payment or furnishing, it is reasonable to believe that the employee will be able to exclude such payment or benefit from income under section 127.
26 C.F.R. §31.3401(a)(18)-1