Missouri law is explicit: Chapter 347 says LLC members shall adopt an operating agreement, and its definition recognizes a written or oral agreement among all members or a written declaration by a sole member. The agreement stays internal, but the Articles of Organization must state whether management is vested in members or managers, so the operating agreement should be drafted to match that filing.
Choose the version that matches your Missouri LLC structure.
Is an Operating Agreement Required in Missouri?
Yes. Missouri is unusually direct on this point. Section 347.081 says the member or members of an LLC “shall adopt an operating agreement.” Missouri then gives members broad freedom to decide what that agreement covers.
The operating agreement is not a formation filing. The Missouri Secretary of State’s Small Business Startup Guide describes it as an internal document that is not filed with the Secretary of State or another government agency. The LLC itself is created by filing Articles of Organization.
Missouri also makes the management choice part of the formation record. The official Articles of Organization, Form LLC 1 requires the organizer to select whether management is vested in managers or members.
Chapter 347 requires adoption of the agreement but does not impose a notarization requirement.
How Missouri Defines an Operating Agreement
“Operating agreement”, any valid agreement or agreements, written or oral, among all members, or written declaration by the sole member concerning the conduct of the business and affairs of the limited liability company and the relative rights, duties and obligations of the members and managers, if any;
That definition creates an important Missouri distinction: a multi-member LLC can have a written or oral operating agreement, while the statutory definition refers specifically to a written declaration for a sole-member LLC.
For an LLC with multiple members, Missouri’s statutory definition recognizes either form. Putting the terms in writing avoids having ownership and governance depend on proving an oral agreement later.
For a one-member LLC, the statute uses the more specific phrase “written declaration by the sole member”. That makes a written single-member document especially important in Missouri.
Missouri makes that policy explicit in § 347.081(2), directing that the LLC statute give maximum effect to freedom of contract and the enforceability of operating agreements. Section 347.081(1) also lets members customize matters such as management authority, voting, transfer restrictions, allocations, and other internal rules within the limits of law.
The Missouri Secretary of State LLC FAQs also explain how this works with management: member-managed LLCs give members management authority, while manager-managed LLCs place that authority with the managers selected under the operating agreement.
Missouri LLC Default Rules When the Agreement Does Not Say Otherwise
Missouri leaves substantial room for private drafting, but Chapter 347 supplies some unusually specific fallback rules when the operating agreement does not say otherwise.
Business matters generally require approval of more than one-half by number of the authorized persons, not automatically a majority of ownership percentages.
§ 347.079(4)Unless the agreement changes the rule, all members must approve certain actions, including amending a written operating agreement, admitting a new member, approving a merger, changing management structure, and taking action outside the usual course of business.
§ 347.079(3)Contributions are returned proportionately first. After that, remaining distributions are shared equally among the members unless the agreement provides another split.
§ 347.101Losses follow contributions already made and promised. Profits first offset prior loss allocations, then follow the members’ post-contribution distribution sharing.
§ 347.111A member may withdraw on 90 days’ prior written notice. If the withdrawal violates a written operating agreement, the LLC may recover damages and offset them against amounts otherwise distributable.
§ 347.121A membership interest is assignable unless the agreement says otherwise, but the assignee generally receives the economic rights only. The assignment does not by itself make the assignee a member or give management rights.
§ 347.115