General Partnership “Aggregate Theory” + AAA Delegation Clause: Partners’ Individual Signatures Can Compel Arbitration and Send Scope to the Arbitrator

1. Introduction

Parties and business structures. Neil Maune (“Maune”) and Marcus Raichle (“Raichle”) operated a law practice as a general partnership known by a fictitious name, the Maune Raichle Law Firm (“MR Law”), without a written partnership agreement. Later, Maune, Raichle, and three others formed an LLC law firm, Raichle Hartley French & Mudd, LLC (“MRHFM”), governed by an operating agreement (“OA”) containing a broad arbitration clause in Section 11.15 that incorporated the American Arbitration Association’s (“AAA”) commercial arbitration rules.

Insurance proceeds dispute. MR Law originally owned and was beneficiary of two $10 million term life policies (one on each partner). After MRHFM formed, MRHFM paid premiums; Raichle’s policy beneficiary was changed to MRHFM, but Maune’s policy continued to list MR Law as beneficiary. When Maune died (July 16, 2023), the $10 million death benefit was paid to MR Law.

Lawsuit and key issues. Maune’s Estate sued MR Law and Raichle, alleging (among other theories) tortious interference, unjust enrichment, and breach of fiduciary duties, all premised on retention of the insurance proceeds. Defendants moved to compel arbitration under the OA. The circuit court denied the motion on the ground that “MR Law is not a party” to the OA and cannot enforce its arbitration clause.

The appeal raised two recurring arbitration questions: (i) who is bound by the arbitration agreement (including whether MR Law can invoke it), and (ii) who decides whether the Estate’s claims fall within the arbitration clause’s scope—court or arbitrator—given the OA’s incorporation of AAA rules (and their delegation clause).

2. Summary of the Opinion

The Supreme Court of Missouri vacated the order denying arbitration and remanded with instructions to sustain the motion to compel arbitration. The Court held:

Missouri follows the aggregate theory of general partnerships: a general partnership has no legal existence separate from its partners. Therefore, treating “MR Law” as a separate non-signatory entity was a foundational error.
Because all partners of MR Law (Maune and Raichle) signed the OA (and thus its arbitration provision), they had authority under § 358.090.3(5) to submit partnership claims/liabilities between them to arbitration.
By incorporating the AAA Rules, the OA included a delegation clause (AAA Commercial Rule R-7(a)) committing “gateway” questions—such as scope/applicability of arbitration—to the arbitrator.
Under Karlin v. UATP Springfield, LLC, because the Estate did not specifically challenge the delegation provision, the court had to compel arbitration and leave scope questions to the arbitrator.

3. Analysis

3.1. Precedents Cited

A. Delegation clauses and “gateway” arbitrability

Brown v. GoJet Airlines, LLC, 677 S.W.3d 514 (Mo. banc 2023): The Court used Brown’s framework identifying the two usual “threshold” issues (existence/enforceability of an arbitration agreement; and scope) and emphasized that parties may agree to arbitrate those gateway questions through a delegation provision. Brown relied on the U.S. Supreme Court’s delegation doctrine.
Rent-A-Center, W., Inc. v. Jackson, 561 U.S. 63 (2010): Quoted via Brown for the proposition that parties can arbitrate gateway questions of arbitrability.
Karlin v. UATP Springfield, LLC, 706 S.W.3d 810 (Mo. banc 2025): This was the controlling Missouri decision. Karlin draws a bright line: when there is a prima facie showing of an arbitration agreement that purports to bind the parties and contains a delegation clause, the court must compel arbitration unless the opponent specifically challenges the delegation clause. A general attack on the arbitration agreement (or arguments about scope) is insufficient.
State ex rel. Pinkerton, 531 S.W.3d 36 (Mo. banc 2017), abrogated on other grounds by Theroff v. Dollar Tree Stores, Inc., 591 S.W.3d 432 (Mo. banc 2020): Pinkerton supported the proposition that incorporating the AAA commercial arbitration rules manifests intent to delegate arbitrability questions to the arbitrator. The Court acknowledged Pinkerton’s partial abrogation but preserved its relevance to delegation-by-AAA-incorporation.
Theroff v. Dollar Tree Stores, Inc., 591 S.W.3d 432 (Mo. banc 2020): Used to explain the limited circumstance where a more deferential standard of review applies—when the factual existence of an arbitration agreement is genuinely disputed (e.g., alleged non-signature and lack of knowledge). The Court distinguished this case because the Estate conceded Maune and Raichle signed the OA.

B. Missouri partnership “aggregate theory” (non-entity status)

Naylor Senior Citizens Hous., LP v. Side Const. Co., 423 S.W.3d 238 (Mo. banc 2014), and Scott v. Edwards Transp. Co., 807 S.W.2d 75 (Mo. banc 1991), overruled on other grounds by Hampton v. Big Boy Steel Erection, 121 S.W.3d 220 (Mo. banc 2003): Cited for the foundational premise that Missouri treats general partnerships as aggregates of partners, not separate legal entities.
Kelley v. DeKalb Energy Co., 865 S.W.2d 670 (Mo. banc 1993): Reinforced that Missouri’s adoption of the Uniform Partnership Act in chapter 358 did not convert general partnerships into distinct legal entities.
Haney v. Thomson, 98 S.W.2d 639 (Mo. banc 1936): Cited for the procedural consequence of aggregate theory—general partnerships cannot sue or be sued in the firm name; partners must be named.
25 Mo. Prac., Business Organization § 5.6(1) (citing Snyder Bros. Co. v. Library Landholders, Inc., 718 S.W.2d 633 (Mo. App. 1986)): Used to support the proposition that partners, not the partnership name, are the proper parties.

C. “Capacity” distinctions: corporations/LLCs versus general partnerships

Tucker v. Vincent, 471 S.W.3d 787 (Mo. App. 2015); Jones v. Paradies, 380 S.W.3d 13 (Mo. App. 2012); and Springfield Iron & Metal, LLC v. Westfall, 349 S.W.3d 487 (Mo. App. 2011): The Estate relied on these cases for the idea that signing “in a corporate capacity” does not bind an individual personally. The Supreme Court of Missouri distinguished them as inapplicable because a general partnership has no separate legal existence; partners do not have a distinct “corporate capacity” analogous to LLC managers/members or corporate officers/directors.
Am. Fed'n. of State, Cnty. & Mun. Emps., AFL-CIO, Council 61 v. State, 653 S.W.3d 111 (Mo. banc 2022): Cited for Missouri’s “cardinal rule” of contract interpretation—ascertain intent from the plain language when unambiguous. The Court used this to read the OA signature blocks stating signers acted “individually and on behalf of the Company.”

D. Nonsignatory enforcement (not reached)

CD Partners, LLC v. Grizzle, 424 F.3d 795 (8th Cir. 2005): Raised as an alternative theory for allowing a nonsignatory to enforce an arbitration agreement, but the Court expressly declined to reach it because it concluded MR Law was not a separate entity from its partners for purposes of the relevant binding analysis.

3.2. Legal Reasoning

A. The Court separated “who is bound” from “what is arbitrable”

A central move in the Court’s reasoning was insisting on a clean distinction between: (1) formation/binding (whether the parties are bound to arbitrate at all), and (2) scope (whether the asserted claims fall within the arbitration clause). The circuit court effectively treated MR Law’s purported nonsignatory status as dispositive and then proceeded to decide (implicitly) that the arbitration clause could not be used. The Supreme Court corrected this by analyzing partnership identity and delegation first.

B. Partnership identity under Missouri’s aggregate theory

The Court held the Estate’s argument depended on a false premise: that “MR Law” is an entity separate from Maune and Raichle. Under Naylor Senior Citizens Hous., LP v. Side Const. Co., Kelley v. DeKalb Energy Co., and related authority, Missouri’s general partnership is an “aggregate”—the partners are the partnership. This undermined the circuit court’s “stranger to the contract” rationale.

C. Authority to arbitrate partnership claims: § 358.090.3(5)

The Court then used § 358.090.3(5) to explain how arbitration authority works in a general partnership: less than all partners lack authority to submit a partnership claim/liability to arbitration, but all partners can do so by signing or authorizing the agreement. Because Maune and Raichle were the only partners, their signatures sufficed to submit partnership claims/liabilities between them to arbitration—subject to the arbitration clause’s scope.

D. “Capacity” argument rejected by (i) partnership theory and (ii) OA’s plain signature language

The Estate argued Maune and Raichle signed only as MRHFM “members/managers,” not as MR Law partners/individuals. The Court rejected this in two ways:

No separate “partner capacity” like a corporate capacity. Unlike corporate officers or LLC managers (as in Tucker v. Vincent and Jones v. Paradies), general partners are not legally distinct from the partnership.
The OA explicitly says “individually.” Applying Am. Fed'n. of State, Cnty. & Mun. Emps., AFL-CIO, Council 61 v. State, the Court read the unambiguous signature page: the members/managers signed “individually and on behalf of the Company.” Thus, the arbitration agreement “purports to bind” Maune and Raichle as individuals.

E. Delegation controls: the arbitrator decides scope because the AAA Rules were incorporated

The Court treated incorporation of the AAA rules as incorporation of a delegation clause (AAA Commercial Rule R-7(a)), consistent with State ex rel. Pinkerton. That triggered Karlin v. UATP Springfield, LLC: absent a challenge directed specifically at the delegation provision itself, courts must compel arbitration and allow the arbitrator to decide disputes over the arbitration clause’s existence/scope/validity as delegated.

Accordingly, the Estate’s contention that its claims do not “arise out of or relate to” the OA was characterized as a scope objection that, under the delegation clause and Karlin, must be decided by the arbitrator—not by the court as a threshold matter.

3.3. Impact

Stronger enforcement of delegation clauses in Missouri. The opinion operationalizes Karlin in a business-organization context: once AAA rules are incorporated and no delegation-specific challenge is raised, Missouri courts will compel arbitration even when scope arguments appear substantial or case-dispositive.
Partnership defendants gain a clearer path to arbitration. Litigants can no longer defeat arbitration simply by naming a general partnership (by firm name) as an alleged nonsignatory “entity” separate from its partners. Where all partners signed the arbitration agreement, courts will treat partnership-related claims as potentially arbitrable and send scope to the arbitrator if delegated.
Pleading/party-naming consequences. The Court’s reaffirmation of Haney v. Thomson (partners must be named) signals that misnaming the partnership as an entity can create avoidable procedural confusion—yet will not, by itself, prevent arbitration when the partner-signatories are before the court.
Estate/successor posture. The opinion assumes the Estate is bound to the same extent Maune was bound (the Estate did not contest that), suggesting that successor representatives should anticipate being held to the decedent’s arbitration commitments—especially when delegation is present.
Practical shift of “scope fights” out of court. Disputes about whether tort, fiduciary-duty, interference, or unjust-enrichment claims “relate to” an operating agreement will increasingly be decided in arbitration when AAA delegation language is used.

4. Complex Concepts Simplified

Aggregate theory (general partnerships): In Missouri, a general partnership is not a separate “person” from its partners. It is legally an association of the partners themselves. That is why the Court says the partners “were MR Law.”
Delegation clause: A delegation clause is an agreement to let the arbitrator decide “gateway” questions like whether a dispute is covered by the arbitration clause. Here, the delegation clause came from incorporating the AAA rules (AAA Commercial Rule R-7(a)).
Gateway questions of arbitrability: These are threshold issues a court often decides before ordering arbitration—e.g., whether an arbitration agreement binds the parties, and whether the dispute falls within the clause’s scope. If there is a valid delegation clause, the arbitrator decides these issues.
“Capacity” to sign (corporate vs. partnership): Corporate/LLC actors can sign “as officer/director/manager” without binding themselves personally (as in Tucker v. Vincent and Jones v. Paradies). General partners are different under Missouri law because the partnership is not separate from the partners—so the “capacity” distinction does not work the same way.
Prima facie showing (in arbitration motions): The moving party must show, on its face, a written arbitration agreement that purports to bind the parties and (here) contains a delegation clause. Once shown, Karlin requires compelling arbitration unless the delegation clause itself is specifically challenged.

5. Conclusion

Maune vs. Raichle reinforces two interlocking Missouri arbitration principles in the partnership/LLC setting: (1) under Missouri’s aggregate theory, a general partnership has no existence separate from its partners, so the partners’ signatures can bind partnership claims/liabilities under § 358.090.3(5); and (2) where an arbitration clause incorporates the AAA Rules, the resulting delegation clause requires courts—under Karlin v. UATP Springfield, LLC—to compel arbitration and leave scope disputes to the arbitrator unless the delegation clause is specifically attacked.

The decision’s broader significance lies in its insistence that courts must not short-circuit delegation by deciding “this dispute doesn’t relate” arguments themselves; once delegation is established and unchallenged, the arbitrator decides what the arbitration agreement covers.