For example, if a plan was adopted on January 2, 1974, effective as of January 1, 1974, the plan is not considered to have been in existence on January 1, 1974, because it was not both adopted and in writing on January 1, 1974.
26 C.F.R. §1.411(a)-2
Sec. 411 (88 Stat. 901; 26 U.S.C. 411 )