Who signs a Plan Doc when multiple owners are not all Ind. Trustees?

Professional firm, each partner with their own corp.

On prior plan document restatements, all of the partners have signed, but for amendments, only the 2 who are designated as Individual Trustees have signed.

I'm curious what the standard approach is? I think the partners like to feel involved, but is it really necessary?

About what’s required:

“Every employee benefit plan shall . . . provide a procedure for amending such plan, and for identifying the persons who have authority to amend the plan[.]” ERISA § 402(b)(3), unofficially compiled as 29 U.S.C. § 1102(b)(3).

Yet, the Supreme Court holds that stating as little as “[t]he Company” may amend the plan is enough to meet ERISA § 402(b)(3)’s two requirements—that a plan “provide a procedure for amending [the] plan, and [a procedure] for identifying the persons who have authority to amend the plan[.]”). Curtiss-Wright Corp. v. Schoonejongen, 514 U.S. 73, 18 Empl. Benefits Cas. (BL) 2841 (Mar. 6, 1995).

For a restatement or other amendment, one looks to the governing documents (as they exist just before the restatement one is about to adopt) to find what the documents require for an amendment of them to be effective.

An IRS-preapproved document likely allows almost anything as an amendment.

About “each partner with their own corp.”, check whether each corporation is a participating employer or a participant. (For situations in which the corporations comprise the partners of the partnership, either configuration is possible.) If a corporation is a participating employer, check that it signs whatever the documents require for an organization to join as a participating employer. Likewise, if the adoption agreement doesn’t name the participating employers, one might add something to show the plan sponsor’s assent.

Whether to do something more than what ERISA, the Internal Revenue Code, and the governing documents require is up to the organizations’ business judgment.

Just to add a thought to Peter's post:  it's important to know what an entity requires in its governing documents for action.  In a partnership, does the partnership require agreement by all partners?  Does the partnership documentation and/or the "resolution" document of the partners (if there is one) authorize someone to act on behalf of the partnership?  Perhaps there is a managing partner that has been so authorized?

The key issue is that the signor on plan document should be someone who is authorized to act on behalf of the entity, whether it's a corporation or a partnership.  (Clearly a sole proprietor can act on behalf of the proprietorship.)  If that authorization is in the governing documents for the company, fine.  If not, you want to have something signed by the Board or whoever is the governing group/person that delegates the authority for signature to the person signing the plan.  (That's why you normally see in a Board resolution some language that says, "Any officer of the Corporation is hereby authorized to adopt such amendment or take such further action as is necessary to carry out these resolutions.")  It can also be a matter of state law.  Under most states, i believe, any general partner (but NOT a limited partner) is authorized to act on the partnership unless the governing documents provide otherwise.