Carpenters Fringe Benefit Funds of Illinois v. McKenzie Engineering, 217 F.3d 578 (8^th Cir. 2000)-The Funds sued for unpaid pension fund contributions. This court reversed the district court after finding that the Funds failed to prove that the collective bargaining agreements required McKenzie to pay the amounts the Funds claimed were due. Under ERISA § 515, a Fund may collect only those contributions that an employer is contractually obligated to pay. In this case, the Funds' audit failed to distinguish between covered and non-covered employees and types of work.

This court further denied the Funds' request that the burden of proving such details be shifted to the employer once genuine questions are raised about the accuracy of the employer's records. See Brick Masons Pension Trust v. Industrial Fence & Supply, Inc., 839 F.2d 1333, 1338 (9th Cir. 1988). Without commenting on the applicability of that case, this court pointed out the Funds simply made a series of invalid assumptions in their audit, so that their claims amounted to nothing more than an "unremedied failure of proof."