Example. Employer A maintains Plan 1 pursuant to a collective bargaining agreement. Plan 1 covers 100 of Employer A's noncollectively bargained employees and 900 of Employer A's collectively bargained employees. Employer A also maintains Plan 2, which covers Employer A's other 400 noncollectively bargained employees. The collective bargaining agreement under which Plan 1 is maintained was entered into on January 1, 1986, and expires December 31, 1992. Because Plan 1 is a plan maintained pursuant to a collective bargaining agreement, section 410(b) applies to the first plan year beginning on or after January 1, 1991. In applying section 410(b) to Plan 2, the 100 noncollectively bargained employees in Plan 1 must be taken into account. The deferred effective date for plans maintained pursuant to a collective bargaining agreement is not applicable in determining how section 410(b) is applied to a plan that is not maintained pursuant to a collective bargaining agreement.
26 C.F.R. §1.410(b)-10