all based, in the case of an employee who is not on retirement benefit under the plan, upon the assumption of his continued employment at his current rate of compensation until his normal retirement age (or the end of the current year if later) and retirement on such date with the normal form of retirement benefit under the plan.
If it is claimed that the requirements of section 401(a)(3)(A) are satisfied, also the data and computations necessary to show that such requirements are satisfied.
In the case of corporate employers, the information required to be submitted by this paragraph shall, except as otherwise provided by the Commissioner, be filed on Form 2950 for taxable years ending on or after December 31, 1961. In the case of other employers, the information required to be submitted by this paragraph shall, except as otherwise provided by the Commissioner, be filed on Form 2950 for taxable years ending on or after December 31, 1962.
26 C.F.R. §1.404(a)-2