Series LLC

A series LLC is a special type of limited liability company that allows a single parent LLC to create multiple sub-units, called "series" or "cells," each with its own assets, liabilities, members, and operating rules. Each series functions as a legally separate compartment within a single overarching entity, providing liability insulation between series.

This structure, first introduced in Delaware in 1996 for the mutual fund industry, is designed for owners who manage multiple business lines, properties, or ventures and want to protect each one from the debts and legal exposure of the others, without forming and maintaining entirely separate LLCs for each.

Not all states recognize the series LLC. As of 2026, states including Delaware, Texas, Illinois, Nevada, and Wyoming have enacted series LLC statutes, but availability and governing rules vary significantly by jurisdiction.

How a series LLC works

A series LLC begins with the formation of a master or parent LLC, which is registered with the state in the same way as a standard LLC. The parent entity then establishes individual series beneath it, each designated in the operating agreement or a separate series designation document.

Each series can hold its own assets, such as real estate, intellectual property, or business operations, and carry its own liabilities. Crucially, if one series faces a lawsuit or debt obligation, the assets of other series and the parent LLC are generally shielded from that exposure, provided the series are properly maintained as separate units.

To preserve liability separation, each series typically requires.

• Separate accounting records and bank accounts
• Clear identification in contracts and agreements as a distinct series
• Proper documentation in the operating agreement governing each series

The parent LLC files one set of formation documents with the state, but the internal governance of each series is defined within the LLC's operating agreement.

Why a series LLC matters

The primary value of a series LLC is liability compartmentalization. A business owner with multiple rental properties, for example, can place each property in its own series. If a tenant sues over one property, the assets held in other series remain protected, assuming the series have been properly maintained.

This structure can also reduce administrative overhead by 60–80% compared with forming multiple standalone LLCs for owners with three or more assets. Instead of filing separate articles of organization, paying separate state fees, and maintaining separate registered agents for each entity, an owner manages one parent LLC with an internal series.

However, the liability protection a series LLC offers is only as strong as the state law recognizing it and the care taken to maintain proper separation between series. Commingling assets or failing to keep distinct records can allow creditors to pierce the protective veil and undermine the entire structure.

Common uses and examples of a series LLC

The series LLC is most commonly used in industries where a single owner manages multiple distinct assets or business activities. Practical examples include:

• Real estate investment. A property investor holds five rental properties, each in a separate series. A slip-and-fall lawsuit at one property cannot reach the equity held in the others.
• Franchise or multi-location businesses. An entrepreneur operating several retail locations under different brands places each location in its own series, keeping their financial exposure isolated.
• Investment funds. A fund manager uses separate series to segregate distinct investment portfolios or investor classes within a single legal entity.
• Licensing and intellectual property. A business owner separates a patent portfolio from an operating business by placing each in a distinct series, protecting IP assets from operational liability.

Key characteristics of a series LLC

The series LLC has several defining traits that distinguish it from a standard LLC.

Single formation filing. Only one set of articles of organization is filed with the state to establish the parent LLC. Individual series are typically created through the operating agreement or a series designation filing, depending on state law.

Internal liability walls. When properly structured and maintained, the debts and obligations of one series do not attach to the assets of another series or the parent entity.

Flexible governance. Each series can have its own members, managers, profit-sharing arrangements, and operating rules, all documented within the master operating agreement or individual series agreements.

Limited state recognition. Because not every state has a series LLC statute, and more states continue to adopt the Uniform Protected Series Act, operating a series LLC across multiple states can still create legal uncertainty. A series formed in Delaware, for instance, may not receive the same liability protection when doing business in a state that does not recognize the structure.

Tax treatment is unsettled. The IRS has not issued comprehensive final guidance on how series LLCs are taxed, and proposed regulations from 2010 remain unfinalized more than 15 years later. Some series may need to file separately; others may be treated as disregarded entities under standard IRS classification rules. Consulting a tax professional is essential before forming a series LLC.

Series LLC vs. standard LLC

A standard LLC is a single legal entity with one pool of assets and liabilities. A series LLC is a single legal entity that contains multiple legally separate compartments. The key distinction is internal liability insulation: A standard LLC cannot wall off one business activity from another within the same entity, while a series LLC is specifically designed to do so.

For owners managing a single business or a simple structure, a standard LLC is typically sufficient. The series LLC is most useful when multiple distinct assets or ventures need to be managed under a single umbrella, with liability separation among them.

Considerations and limitations

State availability. Before forming a series LLC, confirm that the state of formation has a series LLC statute and that the states where the series will operate also recognize the structure.

Maintenance requirements. The liability protection between series depends on strict operational separation. Commingled finances, shared contracts without proper series identification, or inadequate recordkeeping can collapse the liability walls.

Legal and tax complexity. Series LLCs involve more structural complexity than a standard LLC. The operating agreement must be carefully drafted to define each series, its assets, its members, and its governance rules. Given the unsettled federal tax treatment, which the American Bar Association has explored in detail, state-level treatment is equally inconsistent. California imposes its $800 annual LLC tax per series, treating each as a separate entity, making professional legal and accounting guidance strongly advisable before formation.

Lender and counterparty acceptance. Some lenders, title companies, and business partners are unfamiliar with the series LLC structure, which can complicate financing or contract negotiations.

Related terms and next steps

Understanding the series LLC is easier in context with related LLC structures and governance concepts. Key terms worth reviewing include:

• Multi-member LLC. A standard LLC with more than one owner; relevant when comparing governance structures across series
• Single-member LLC. A one-owner LLC; useful context for understanding how a series LLC can be owned by a single individual managing multiple series
• Operating agreement for an LLC. The governing document that defines each series within a series LLC; it’s critical to the structure's legal integrity
• Domestic limited liability company. Explains how LLCs are registered and recognized within a state, which is foundational to understanding series LLC formation
• Professional LLC. Another specialized LLC type; useful for comparing when a series LLC versus another LLC variant is appropriate

For those considering a series LLC, forming the parent entity correctly from the start is essential. LegalZoom's LLC formation services can help establish the foundational entity, and consulting with an attorney through LegalZoom's legal plan can help ensure the operating agreement properly documents each series.

FAQs about series LLCs

What is the difference between a protected series and a registered series?

A protected series is created entirely within the parent LLC's operating agreement, without filing any separate documents with the state, while a registered series requires its own filing with the state and receives formal recognition, including, in states like Delaware and Texas, the ability to obtain a certificate of good standing. Registered series are generally more useful when a series needs to open bank accounts, secure financing, or enter into contracts independently, since counterparties can verify its existence through state records.

Does each series in a series LLC need its own EIN?

Because the IRS has not finalized guidance on series LLC taxation, the answer depends on how each series is classified for federal tax purposes. A series treated as a separate entity for tax purposes will generally need its own employer identification number (EIN), while one treated as a disregarded entity may not. Given that proposed IRS regulations from 2010 were never finalized, consulting a tax professional before making any EIN decisions is the only reliable way to get this right for a specific structure.

Can a series LLC formed in Delaware do business in a state that doesn't recognize the structure?

A Delaware series LLC can operate in non-recognizing states, but the inter-series liability protection it relies on may not be honored there. A court in a state without a series LLC statute has no legal framework obligating it to treat the series as separate entities. Owners who manage assets or operations across multiple states should confirm with legal counsel how each state in which they do business treats the structure before relying on it for liability protection.

Is a series LLC a good fit for a business owner with only one or two assets?

For owners managing one or two assets, the administrative requirements and legal complexity of a series LLC typically outweigh the benefits. Separate records, separate bank accounts, and a carefully drafted operating agreement are all required to preserve the liability walls, and those obligations exist regardless of how few series are in use. A standard LLC, or multiple standalone LLCs, is generally a simpler and more straightforward solution at that scale.

Can insurance policies cover a series LLC and all of its series under a single policy?

Many insurance carriers are not equipped to properly underwrite a series LLC structure, which can result in coverage gaps. A single policy may not clearly extend to each series as a distinct insured unit, leaving some series exposed in ways the owner may not anticipate. Owners of a series LLC should work with an insurance broker who is familiar with the structure and can confirm that each series carrying meaningful assets or operational risk is adequately covered.

How does bankruptcy work for a series LLC if one series becomes insolvent?

The treatment of a series LLC in federal bankruptcy court remains legally unsettled, because bankruptcy is governed by federal law and the series LLC is a creature of state statute; there is no established precedent confirming that a bankruptcy filing by one series will be contained to that series alone without affecting the others. Owners relying on the series structure for asset protection in high-risk ventures should factor this uncertainty into their planning and discuss it with a bankruptcy attorney before assuming the inter-series liability walls will hold in a federal proceeding.