Related employers.
(B) Related employers. Service with an employer is treated as service for certain related employers for the period during which the employers are related. These related employers include members of a controlled group of corporations (within the meaning of section 1563(a), determined without regard to subsections (a)(4) and (e)(3) (C) thereof) and trades or businesses (whether or not incorporated) which are under common control (see section 414 (b) and (c) and 29 CFR Part 2530, Department of Labor regulations relating to minimum standards for employee pension benefits plans).