Pension Benefit Guaranty Corporation 94-5 Septembe r 27, 1994 RE FERENCE: [*1] 4 211 Withdrawal Liability >29 CFR 2644 .2(d)> OP INION: I writ e in response to your letter requesting clarification o f PBGC Opinion Letter 90-2 to the extent it addressescalc ulation of unf unded vested benefits for purposes of section 4211 of the Employee Re