The Complete Series LLC Guide (2026)
A Series LLC can create internal liability compartments, but it is not one uniform national product. States differ on terminology, formation, per-series filings, asset-record requirements and foreign recognition. Florida's protected-series law is now effective, Texas distinguishes protected and registered series, Delaware has both protected and registered series, and Illinois requires a filing for each designated series.
What is a Series LLC?
A Series LLC is an LLC formed under a state law that permits one LLC to establish separate internal series with their own rights, assets, liabilities or business purposes. If the statute’s conditions are satisfied, liabilities associated with one protected series may be limited to that series rather than reaching the parent LLC or another series. But the mechanics are not uniform: Delaware distinguishes protected and registered series, Texas distinguishes protected and registered series, Illinois requires a Certificate of Designation for each series, and Florida—effective July 1, 2026—requires a protected series designation filing.
What a Series LLC Actually Is
Series terminology and legal effects depend on the jurisdiction. Distinguish the parent LLC from the types of series recognized by the applicable statute, and confirm each series’s formation, registration and liability requirements.
Those internal series can have separate assets, obligations and business purposes. Florida expressly treats a protected series as a person distinct from the series LLC, another protected series and specified owners/transferees. Delaware permits separate rights, powers and duties tied to specified property or obligations.
Verified 2026 State Examples
Instead of publishing an unverified “roughly 20 states” count as if every statute were equivalent, this guide uses current verified examples and tells readers to check their own filing jurisdiction before acting.
| Jurisdiction | Verified current structure | Important filing point |
|---|---|---|
| Florida | Protected-series regime effective July 1, 2026 | Protected series established by filing a protected series designation; member approval required |
| Delaware | Protected series and registered series | Protected-series liability requires statutory conditions; registered series requires a certificate filing |
| Texas | Protected series and registered series | Protected series need not have a separate certificate; registered series requires a certificate and current $300 filing fee |
| Illinois | Series LLC with individually designated series | Series-capable Articles currently $400; each series requires Certificate of Designation |
| Wyoming | Series LLC formation expressly supported | Secretary of State publishes dedicated Series LLC Articles of Organization |
| Nevada | Statute authorizes series of members/managers and series treatment | Confirm current articles/operating-agreement requirements before creating a series |
Why no national count here? States can authorize domestic formation, foreign recognition, protected series, registered series, or another variant. A raw “number of states” can hide meaningful legal differences and becomes stale quickly.
Florida's New Protected-Series Law
Florida is now a major 2026 update. Beginning July 1, 2026, Chapter 605 governs domestic and foreign protected-series structures transacting business in Florida. A Florida LLC establishes a protected series by obtaining the required member approval and filing a protected series designation with the Department of State.
Florida also requires the protected-series name to begin with the parent series LLC’s name and contain “protected series,” “P.S.” or “PS.” The statute gives each protected series capacity to sue and be sued in its own name and treats a protected series as distinct from the parent and other protected series for specified purposes.
How the Internal Liability Shield Really Works
Separate records, assets and business practices can be conditions for series liability protection. The governing jurisdiction determines the legal consequences of failing those conditions; commingling does not have one automatic nationwide result.
Delaware’s protected-series statute expressly conditions internal liability protection on, among other things, the LLC agreement providing for the limitation, notice in the certificate of formation, and records that account for the assets associated with each protected series separately. Delaware even explains that the records can identify assets through specific listing, category, formula or another objectively determinable method.
Florida’s new regime likewise uses detailed associated-asset records. An asset is treated as associated with a protected series only when the series maintains records identifying that asset with enough specificity to distinguish it and trace how it was acquired.
Better rule: maintain truly separate accounting, contracts, asset schedules and—where practical—banking for every series. But do not tell users that a separate bank account is the universal statutory test or that one bookkeeping mistake automatically destroys every internal shield nationwide.
Cross-State Recognition: A Real Issue, but Avoid Overstating It
When a series operates in a jurisdiction that does not authorize domestic series LLCs, check foreign qualification, internal-affairs rules, liability limitations, title ownership and litigation treatment. Recognition is a jurisdiction-specific question.
Texas’s Secretary of State explicitly warns that not all states recognize series LLCs and tells businesses to contact the filing official in each other state where they plan to transact business. That is the right model for LLC School: verify the destination state instead of assuming recognition or non-recognition.
Federal Tax Treatment
In 2010, Treasury and the IRS issued proposed regulations providing that a domestic series can be treated as an entity formed under local law for federal tax purposes, with classification then determined under the ordinary entity-classification rules. The proposal remains an important reference point, but proposed regulations are not the same thing as finalized regulations.
Therefore, do not automatically promise that every series “gets its own EIN” or “files its own return.” The correct filing depends on whether the series is treated as a separate entity, its owners, activities and tax classification. A CPA familiar with Series LLCs should map the federal and state tax treatment before implementation.
Series LLC Costs: Why the Old $110–$400 Range Was Misleading
Budget for the parent entity and every applicable series separately. Filing fees, registrations, annual reports and taxes can apply at different levels. The following examples illustrate why a parent filing alone is not a nationwide all-in price.
| State | Current verified filing example | Why cost scales differently |
|---|---|---|
| Illinois | Series-capable Articles of Organization: $400 | Each individual series also requires a Certificate of Designation |
| Texas | Registered-series certificate: $300 | Protected series and registered series use different filing models |
| Florida | Protected-series designation filing required | Each protected series is established through its own designation filing |
| Delaware | Protected and registered models coexist | Registered series have separate certificate filings and related state fees |
| Wyoming | Dedicated Series LLC Articles available | Series disclosure/record mechanics differ from Illinois/Texas |
Banking, tax preparation, title work, insurance, bookkeeping, state qualification and registered-agent requirements can also make the total ownership cost much closer to separate LLCs than the initial formation fee suggests.
Series LLC vs Separate Standalone LLCs
| Factor | Series LLC | Separate LLCs |
|---|---|---|
| Legal architecture | One LLC framework with internal protected/registered series | Each LLC independently formed |
| State filing duplication | Can be lower, but varies sharply by state and series type | Full formation/compliance for each LLC |
| Cross-state familiarity | More state-specific | Conventional LLC structure widely recognized |
| Asset/accounting discipline | Must clearly associate assets and obligations with each series | Separate legal entities naturally create separate records |
| Lender/title/insurance review | May require extra explanation or documentation | Usually more familiar to third parties |
| Best fit | Multiple distinct assets/ventures in supportive jurisdictions with disciplined administration | Cross-state portfolios or owners prioritizing structural simplicity/certainty |
What to Maintain for Each Series
Asset records
Identify which assets belong to which series with enough specificity to satisfy the governing statute.
Accounting records
Track revenue, expenses, liabilities, capital contributions and inter-series transactions separately.
Series-specific contracts
Make clear which series—not just the parent—is entering the contract when that is the intended obligor.
Separate banking where practical
Often a strong operational control, but do not confuse good practice with the exact statutory test in every state.
Foreign-state review
Before an asset or operation crosses state lines, confirm registration and liability treatment there.
Tax map
Determine whether each series is treated separately for federal/state purposes and what EIN/return rules apply.
Series LLC Fit & State Navigator
This tool avoids pretending that a simple “yes/no state list” resolves the legal analysis. It identifies the next verified issue to check.
Florida: file a protected-series designation
Florida's protected-series regime is effective July 1, 2026. Establishing a protected series requires the statutory member approval and a protected-series designation filing. Confirm the current Department of State filing mechanics and fee before creating each series.
Review Florida's 2026 rules →Where Northwest Fits
Series LLC formation support is state-specific
Northwest publishes state-specific Series LLC formation guidance and can be relevant for formation or registered-agent support in jurisdictions it serves. But do not assume the ordinary LLC formation workflow covers every protected or registered series filing. Confirm the exact state, series type and any per-series filing before purchasing.
Check Northwest's current Series LLC support →Affiliate link. Series LLC availability, per-series filings and pricing vary by state.
Primary Sources & Verification
Ahmad Adil
This guide was rechecked against current Florida, Delaware, Texas, Illinois, Wyoming, Nevada and IRS materials in August 2026. It intentionally avoids a single nationwide state count or generic cost range where the underlying legal structures and filing models differ.
About Ahmad Adil →