Tampa Maritime Association-International Longshoremen’s Association Pension Plan and Trust (“AppeEant”) appeals the district court’s grant of summary judgment in favor of Tampa Bay International Terminals (“Ap-peEee”). AppeEant asserted in a letter to AppeEee, dated May 28, 1993, that AppeEee was an employer subject to withdrawal EabEity under Section 3(5) of the Employee Retirement Income Security Act of 1974 (“ERISA”), 29 U.S.CA. §§ 1001-1461 (West 1985 & Supp. 1995), and demanded payment of such withdrawal EabEity. AppeEee filed an action seeking declaratory judgment that it was not subject to withdrawal EabEity on grounds that it was not an “employer” within the meaning of ERISA as amended by the Multi-Employer Pension Plan Amendments Act (“MPPAA”), 29 U.S.CA. §§ 1381-1453 (West 1985 & Supp. 1995). AppeEant answered and counterclaimed to collect Appel-lee’s aEeged withdrawal EabEity. Both sides moved for summary judgment, and the district court granted summary judgment in favor of AppeEee.

This appeal presents a straightforward question of law: whether AppeEee is an “employer” for purposes of ERISA, as amended by the MPPAA, even though AppeEee is not contractuaEy obEgated to contribute to AppeEant.

AppeEant argues essentiaEy that because AppeEee bears some of the haEmarks of a common law “employer,” AppeEee should be considered an “employer” under the MPPAA. The definition of “employer,” however, is a matter of federal law. See Carriers Containers Council v. Mobile S.S. Ass’n, 896 F.2d 1330, 1343 (11th Cir. 1990). In Carriers Containers, this Court adopted the “contributing obEgor” test for determining whether an entity is an “employer” under the MPPAA. A “contributing obEgor” is one who is “obEgated to contribute to a plan for the benefit of a plan’s participants.” Id.

We are persuaded by the Eighth Circuit’s appEcation of the “contributing obEgor” test under circumstances nearly identical to this case. See Seaway Port Authority of Duluth v. Duluth-Swperior ILA Marine Ass’n Restated Pension Plan, 920 F.2d 503 (8th Cir. 1990). In Seaway, the Eighth Circuit held that a party must be contractuaEy bound to make pension contributions in order to be an “employer” under MPPAA. Id. at 509. We beEeve that this is the best reading of Carriers Containers and is consistent with the treatment that other Circuits have given to withdrawal EabEity under ERISA as amended by MPPAA

*341 Accordingly, we conclude that this appeal is without merit.

AFFIRMED.