Series LLC (master / protected series) (2026)

A series LLC is a state-law structure — available only in some states — that can create internal “series” with segregated assets and liabilities under one master LLC when the statute’s notice, records, and operating-agreement conditions are met. It is not a federal entity type, banks and counterparties may not treat series like separate LLCs, and it is not a substitute for separate LLCs or proper insurance. Short path: confirm the home-state series path → read notice / records / OA conditions → compare series vs separate LLCs vs insurance → ask banks and counterparties how they title series → file only if the statute fits, then run post-acceptance desks.

Neighbor desks: Merge LLCs · Domesticate an LLC to another state · Foreign qualification for an LLC · Foreign LLC and certificate of authority · Operating agreement basics · LLC vs corporation · Single-member vs multi-member LLC · First business checking account · Get an EIN · After you form an LLC · the 50-state formation index.

Short version for 2026: confirm home-state series path → notice + records + OA → compare vs separate LLCs / insurance → ask banks → file only if the statute fits. Delaware publishes § 18-215 (protected series) and § 18-218 (registered series); Texas publishes series FAQs under BOC Ch. 101 (protected vs registered; Form 205 notice language); Illinois publishes series articles / designation under 805 ILCS 180/37-40; Florida’s Uniform Protected Series Provisions under Ch. 605 are effective July 1, 2026. Confirm instruments and fees on the official portals — Formation Lane invents no 50-state series map or liability-firewall guarantee.

What is a series LLC?

A series LLC is a state-law LLC structure available only in some states. Where the statute allows it, a master (umbrella) LLC can establish internal “series” that hold segregated assets and liabilities under published conditions. It is not a federal entity type or a substitute for separate LLCs. Confirm availability, notice, records, and OA language on your SOS.

Five desk steps to map a series LLC path before you file:

1. Confirm the home state publishes a series LLC path. On the formation-state SOS (or equivalent) site and LLC act materials, look for series, protected series, registered series, or designated-series language. If none exists, stop — do not invent availability from a national blog.
2. Read statutory notice, records, and OA conditions. Where series exists, statutes usually require public notice, separate records/accounts, and operating-agreement language. Map those requirements before you rely on asset segregation between series.
3. Compare series vs separate LLCs vs insurance. Series is not automatically a cheaper substitute for separate LLCs or proper liability insurance. Decide which desk actually answers the risk you are trying to isolate.
4. Ask banks and counterparties how they treat series. Before filing, ask the bank, landlord, lender, or title desk whether they will title accounts or contracts to a series — many will not treat series like separate LLCs.
5. File only if the statute fits, then run post-acceptance desks. Use the official SOS instrument for series when the state publishes one. After acceptance: EIN where required, banking the bank will accept, written OA with series language, agent, renewals — see after-you-form.

Desks for the steps: combining separate filing entities — merge LLCs; home-state move — domesticate; second-state entry without changing home — foreign qualification; the private contract that usually carries series language — operating agreement.

How do series relate to the master / parent LLC?

A series sits inside the master (parent / umbrella) LLC under the formation-state statute — not a separate SOS filing entity like a second LLC. The master’s certificate/articles and OA typically carry series authority and liability-limitation notice. Whether each series can contract, hold title, or sue in its own name is statute- and OA-specific — confirm on the official code.

Completing a series filing does not guarantee that another state’s courts, a bank, or an insurer will treat each series like a separate LLC. Meeting statutory notice and records conditions is necessary where the statute says so — it is not a promise of outcome. Membership count remains its own desk — single- vs multi-member.

How does liability, notice, and records work between series?

Segregation is conditional, not automatic. Where series statutes exist, limited liability between series usually depends on public notice (often on the certificate/articles), separate records and accounts, and OA language establishing the series. Courts, other states, banks, and insurers may still treat series differently than separate LLCs. Confirm notice and records conditions on your formation-state statute with counsel.

Examples of public starting pages (confirm current forms and fees at filing time — not a national eligibility list):

• Delaware Code — Title 6, Ch. 18, Subchapter II (§ 18-215 protected series; § 18-218 registered series) (notice in the certificate of formation + separate records + LLC agreement for protected-series limitation; registered series adds a certificate of registered series filing)
• Texas SOS — Formation FAQs (Series LLCs) (Form 205 + § 101.602 notice language; protected series created under the company agreement without a creation filing; registered series = certificate of registered series, published fee $300 — confirm at filing; foreign series LLC → Form 313)
• Illinois — 805 ILCS 180/37-40 · IL SOS LLC forms index (series articles Form LLC-5.5(S) and certificate-of-designation path — confirm live fees)
• Florida Sunbiz — LLC forms index (Protected Series Forms) · About Florida Series LLCs (Ch. 605 Uniform Protected Series Provisions effective July 1, 2026; online Designation of Protected Series published at $25 per series — confirm at filing)

Is a series LLC available in every state?

No — not every state. Series / protected-series / registered-series LLC statutes exist only in some jurisdictions. This page does not invent or maintain a 50-state list. Open the home-state SOS business-entity / LLC act materials and look for series, protected-series, or designated-series language. If the official pages are silent, do not assume a national blog made series available.

• Formation-state statute first — series / protected series / registered series / designated series language on the LLC act and SOS forms index.
• Portal orientation only — use the matching form-LLC guide on this site to find the SOS portal; never treat this site as proof that series exists in that state.
• Foreign recognition is separate — even if home-state series works, a second state may treat the master LLC as one entity (Texas Form 313 pattern) or may not recognize series at all: Foreign qualification.
• Not a merger of separate LLCs — internal series structure is not a statutory merger of separate filing entities: Merge LLCs.

Texas SOS expressly notes that not all states recognize a series LLC and that you should contact the other state’s filing official before relying on series abroad. Florida’s July 1, 2026 protected-series rollout adds designation / change / cancel / dissolve filings for Florida LLCs and foreign protected-series CoA forms — still confirm live on Sunbiz.

What about tax, banking, and foreign recognition of series?

Banks and counterparties do not reliably treat each series like its own LLC — ask KYC desks before you file. Federal tax classification and whether each series needs its own EIN sit on IRS materials and CPA judgment. Foreign qualification is a separate SOS desk; other states may not recognize series the same way. Confirm on both portals with counsel.

• Banks / KYC — ask before you file; checking primer: First business checking account.
• OA / series schedules — usually where series are established and tied to asset pools: Operating agreement basics.
• EIN / tax classification — free EIN where required; series-as-entity and multi-EIN questions are CPA work on current IRS materials (LLC page, Pub. 3402, and any live series regs — do not invent from a blog).
• Second-state desks — Foreign qualification · Foreign LLC / CoA · home-state change: Domesticate.

After the master LLC / series filing is accepted: save the stamped packet, keep series schedules and account statements segregated the way the statute and OA require, open banking only in a title the bank will accept, keep the registered agent reachable, and calendar SOS renewals. First-month shape: After you form an LLC.

Series LLC FAQ

What is a series LLC?

A series LLC is a state-law LLC structure available only in some states. Where the statute allows it, a master (umbrella) LLC can establish internal “series” that hold segregated assets and liabilities under published conditions. It is not a federal entity type or a substitute for separate LLCs. Confirm availability, notice, records, and OA language on your SOS.

How do series relate to the master / parent LLC?

A series sits inside the master (parent / umbrella) LLC under the formation-state statute — not a separate SOS filing entity like a second LLC. The master’s certificate/articles and OA typically carry series authority and liability-limitation notice. Whether each series can contract, hold title, or sue in its own name is statute- and OA-specific — confirm on the official code.

How does liability, notice, and records work between series?

Segregation is conditional, not automatic. Where series statutes exist, limited liability between series usually depends on public notice (often on the certificate/articles), separate records and accounts, and OA language establishing the series. Courts, other states, banks, and insurers may still treat series differently than separate LLCs. Confirm notice and records conditions on your formation-state statute with counsel.

Is a series LLC available in every state?

No — not every state. Series / protected-series / registered-series LLC statutes exist only in some jurisdictions. This page does not invent or maintain a 50-state list. Open the home-state SOS business-entity / LLC act materials and look for series, protected-series, or designated-series language. If the official pages are silent, do not assume a national blog made series available.

What about tax, banking, and foreign recognition of series?

Banks and counterparties do not reliably treat each series like its own LLC — ask KYC desks before you file. Federal tax classification and whether each series needs its own EIN sit on IRS materials and CPA judgment. Foreign qualification is a separate SOS desk; other states may not recognize series the same way. Confirm on both portals with counsel.

Does a series LLC replace separate LLCs or insurance?

No — treat that claim as marketing, not a desk map. Even where series statutes exist, segregation usually depends on meeting published conditions (notice on the public record, separate records/accounts, OA language). Courts, other states, banks, landlords, and insurers may still treat the structure differently than separate LLCs. Liability insurance and separate entities remain separate decisions. Formation Lane does not give liability or insurance advice.

How does a series LLC relate to single- vs multi-member or LLC vs corporation?

Series is a state structure question inside the LLC family — not the same desk as membership count (single- vs multi-member) or choosing LLC vs corporation at the SOS (LLC vs corporation). You still decide who owns what, how the OA reads, and whether corporation articles are even on the table. Series does not replace those choices.

Do I still need an operating agreement, EIN, and post-formation desks?

Usually yes — and the OA is often more important for series because statutes typically require series language, asset segregation procedures, and notice. Keep a written operating agreement with company records. After the master LLC exists: free EIN where required, banking titled the way the bank will accept, registered agent, renewals. First-month shape: After you form an LLC. Whether each series needs its own EIN or tax filing is a CPA question on current IRS materials — not something this page invents.

Is forming a series LLC the same as foreign-qualifying or domesticating?

No. Foreign qualification / certificate of authority is a separate SOS desk when you do regular business in a second state — Foreign qualification for an LLC · Foreign LLC and certificate of authority. Domestication changes the home state of formation — Domesticate an LLC to another state. A series formed under one state’s statute may not be recognized the same way elsewhere. Confirm on both states’ SOS pages and with counsel.

Is this page legal advice on whether I should use a series LLC?

No. Formation Lane publishes a setup / desk map: what a series LLC usually is, that availability is state-specific, that banks and counterparties may not treat series like separate LLCs, and that series is not a substitute for separate entities or insurance. Whether series fits your facts — and how courts would treat segregation — is fact-specific. Confirm on your SOS and with a qualified professional when the stakes are real.

What this page does not cover

• A list of which states allow series LLCs — confirm on your SOS.
• Invented SOS filing fees, series designation fees, or a national liability-firewall guarantee.
• Whether series segregation will hold in court for your facts — ask qualified counsel.
• Whether series replaces separate LLCs or insurance for any particular risk.
• How many EINs or tax returns each series needs — CPA on current IRS materials.
• Statutory merger of separate filing entities — Merge LLCs.
• Home-state change while remaining an LLC — Domesticate an LLC to another state.
• Drafting series operating agreements or filing articles for you. Formation Lane is a publisher only.