This article is general information, not legal or tax advice. State filing fees, franchise taxes, and series statutes change frequently and vary by filing type — confirm every dollar figure with the relevant Secretary of State before filing. Figures reflect published fee schedules as of mid-2026 where available; ranges are used where period-specific data could not be confirmed against a primary source.
TL;DR — Quick Verdict
- Roughly 20 states plus Puerto Rico and D.C. authorize Series LLCs by statute — Delaware, Texas, Illinois, Nevada, Tennessee, and Wyoming are the most commonly used.
- The core economic argument: one parent filing plus internal series, instead of paying a separate formation fee and annual report fee for each entity. For an owner running five separate LLCs, avoided annual costs commonly land in the $500–$2,000 range depending on state.
- Illinois is the outlier — it requires a public filing and a separate fee for each series, which erases most of the cost advantage in that state.
- The inter-series liability shield has almost no appellate case law testing it, and courts outside the enacting state are not obligated to respect it. That is the real risk, not the filing cost.
- Series LLCs make sense for in-state real estate portfolios of three or more properties held long-term. They are a poor fit for operating businesses, multi-state footprints, or anyone who needs conventional bank or SBA financing.
A landlord holding six rental properties in traditional single-member LLCs pays six formation fees, six annual report fees, and often six registered agent subscriptions. In a state where the annual report runs $50 and registered agent service runs $125, that is roughly $1,050 a year in pure administrative overhead before a single repair is made. The Series LLC was designed to collapse that stack into one filing.
Delaware wrote the first series statute in 1996, and the structure has since spread to roughly twenty states. Formation services including Northwest Registered Agent, ZenBusiness, and Wolters Kluwer’s CT Corporation all market series formation, typically at the same base price as a standard LLC. That pricing parity is exactly why the structure looks so attractive on a spreadsheet — and why the spreadsheet is misleading.
This analysis covers which states authorize series, what the parent-plus-series structure actually costs in the highest-volume jurisdictions, how the liability shield is supposed to work and where it has never been tested, the specific mistakes that collapse the shield, and a conditional test for whether the structure fits a given portfolio.
Which States Authorize Series LLCs — and How the Statutes Differ
Statutory authorization is not uniform. Three distinct models exist, and the model determines the cost.
Delaware, Texas, Nevada, Tennessee, Utah, Oklahoma, Kansas, Montana, Missouri, Iowa, Alabama, Arkansas, Indiana, North Dakota, Wyoming, Virginia, Nebraska, Wisconsin, the District of Columbia, and Puerto Rico each have series provisions in their LLC acts, though the count shifts as legislatures amend their codes. A second group — most visibly Illinois — authorizes series but requires each one to be publicly filed. California does not authorize domestic Series LLCs at all, yet it will tax a foreign Series LLC doing business in the state, treating each series as a separate entity for franchise tax purposes.
That California treatment is the single most expensive surprise in this structure. An owner who forms a Delaware Series LLC and then operates rental property in California can face a separate minimum franchise tax obligation for each series with California nexus. The savings from consolidating formation fees vanish immediately. Anyone considering an out-of-state parent should read the Wyoming vs Delaware out-of-state formation costs comparison first, and understand the registering an LLC in another state requirements that follow.
Uniformity is improving slowly. The Uniform Protected Series Act, promulgated by the Uniform Law Commission in 2017, gives states a common template for series formation, dissolution, and creditor rights. Adoption has been partial. Until it is widespread, a series formed in one state carries no guarantee of recognition in another.
What a Series LLC Actually Costs Versus Separate LLCs
Cost breaks into four components: the parent formation fee, any per-series filing fee, annual report or franchise obligations, and registered agent service. Only the second component varies dramatically by state.
Figures are defensible ranges, not confirmed point figures — period-specific fee schedules could not be verified against primary sources at publication. Confirm current amounts with each state directly: Delaware Division of Corporations (verify at corp.delaware.gov), Texas Secretary of State (verify at sos.texas.gov), Illinois Secretary of State (verify at ilsos.gov), Nevada Secretary of State (verify at nvsos.gov), Wyoming Secretary of State (verify at sos.wyo.gov).
Run the arithmetic on a five-property Texas portfolio. Five separate LLCs at the state’s formation fee means roughly $1,500 in one-time filing costs, plus five franchise tax reports and, if outsourced, five registered agent subscriptions. One Series LLC with five internal series means a single formation fee, one franchise tax report, and one registered agent relationship. First-year savings land in the $1,200–$1,800 range; ongoing annual savings come almost entirely from consolidated registered agent and compliance work. Current per-state formation numbers are tracked in the LLC formation filing fees and annual costs by state breakdown, and agent pricing spreads are covered in the registered agent service cost comparison.
What that math omits is legal drafting. A functioning Series LLC needs a master operating agreement plus a separate series designation agreement for each series, and generic templates rarely handle series properly. Attorney drafting for a multi-series structure typically runs several multiples of a standard single-entity agreement — the spread between template and attorney work is detailed in the operating agreement attorney costs vs templates analysis.
How the Inter-Series Liability Shield Is Supposed to Work
Picture a duplex in Series A and a four-unit building in Series B, both under one parent LLC. A tenant in the four-unit building wins a $400,000 judgment. Under the series statute, that creditor should be able to reach only Series B’s assets — the duplex in Series A stays untouched, as does the parent’s own property.
Statutory conditions apply, and they are strict. Records must be maintained so that the assets of each series are separately identifiable. Each series generally needs its own bank account, its own accounting, and title held in the name of that specific series rather than the parent. Deeds should name “Parent LLC — Series B,” not “Parent LLC.” Miss the record-keeping condition and the statutory shield does not apply — the series collapses into a single pool of assets.
Here is where the structure diverges from a portfolio of separate LLCs. A separate LLC’s liability shield rests on decades of case law across every state. The inter-series shield rests on a statute drafted in the last thirty years with very little appellate testing — and essentially none in bankruptcy, where a trustee may argue the parent and all series constitute one estate. A court in a non-series state hearing a dispute over property located there has no statutory obligation to honor another state’s series partition. The general limits of entity protection are covered in what limited liability protects and what it doesn’t.
Series LLC vs Separate LLCs: Which Is Better for a Rental Portfolio?
Separate LLCs cost more and work everywhere. Series LLCs cost less and work in a narrower set of circumstances. The choice turns on three variables: property count, geographic concentration, and financing needs.
Comparison synthesized from state LLC statutes and IRS proposed rulemaking on series treatment; verify federal treatment at irs.gov and confirm lender policy directly with the institution. Internal Revenue Service (verify at irs.gov).
Verdict
For three or more residential properties held long-term in a single series state, owned free and clear or financed by portfolio lenders who have already approved the structure, the Series LLC wins on cost. For anyone with properties in multiple states, anyone who expects to seek conventional or SBA financing, or anyone operating an active business rather than holding passive assets, separate LLCs win — the incremental filing cost buys a liability shield that courts everywhere already recognize. The deciding question is not what the structure costs to create. It is what it costs to defend.
What Most People Get Wrong About Series LLCs
Five errors account for most failed series structures, and four of them are administrative rather than legal.
Mistake 1: Titling property in the parent’s name. A deed reading “Sunset Holdings LLC” rather than “Sunset Holdings LLC — Series B” places the asset outside the series. The consequence is total — the property sits in the general pool and any creditor of any series can reach it. Correct action: record title in the exact series name, and correct existing deeds before adding new assets.
Mistake 2: Running one bank account for all series. Commingled funds defeat the separate-records condition every series statute imposes. A plaintiff’s attorney will find this in discovery within one document request. Correct action: open a dedicated account per series, with the account titled to the series.
Mistake 3: Assuming the shield travels. Forming in Delaware or Texas and buying property in a non-series state exposes the entire structure to a court with no obligation to honor the partition. Correct action: form in the state where the assets sit, or accept that the inter-series shield may not survive litigation there.
Mistake 4: Treating the federal tax filing as settled. Proposed IRS regulations would treat each series as a separate entity for federal tax purposes, but they were never finalized. That leaves EIN issuance, return filing, and elections in a gray zone requiring a CPA who has actually handled series returns. Owners weighing an entity election should review the LLC vs S-Corp tax savings by profit level analysis before layering a series structure onto it.
Mistake 5: Skipping the series designation agreement. A master operating agreement alone does not create a series. Each one requires its own written designation identifying its assets, members, and management. Without it, the series may not legally exist despite appearing in internal records.
Who Should Use a Series LLC — and Who Should Not
Conditional logic beats a blanket recommendation here.
Use a Series LLC if: assets sit in one series state and stay there; the portfolio holds three or more discrete assets; the assets are passive holdings such as rental real estate or equipment; financing comes from cash, private lenders, or a portfolio lender who has confirmed acceptance in writing; and a CPA and attorney familiar with series structures are engaged from the start.
Avoid a Series LLC if: the portfolio spans multiple states; conventional, agency, or SBA financing is anticipated; the business is an active operating company with employees and vendor contracts; the state is Illinois, where per-series fees erase most of the savings; or California nexus exists, where each series may face separate franchise tax obligations.
A middle path exists. A holding company owning several conventional subsidiary LLCs delivers comparable segregation using entity law that every court and lender already understands. It costs more in filing fees and buys certainty in exchange. Owners running two properties or fewer usually find the savings too small to justify the complexity — at that scale, the analysis in single vs multi-member LLC tax treatment and sole proprietor vs LLC liability and tax differences matters more than series availability. And structures do get unwound: exit costs are covered in dissolving an LLC without residual liability.
Frequently Asked Questions
Does each series need its own EIN?
Practice is unsettled. Proposed IRS regulations would treat each series as a separate entity for federal tax purposes, which implies separate EINs, but those regulations were never finalized. Many practitioners obtain an EIN per series anyway, since banks generally require one to open a dedicated account and separate accounts are a statutory condition of the shield. Confirm current guidance at irs.gov with a CPA experienced in series filings.
Can I convert existing separate LLCs into a Series LLC?
Yes, but the transfer of property into series triggers deed recording, potential transfer taxes, and lender due-on-sale clause exposure on any mortgaged property. Existing loans generally must be assumed or refinanced. For portfolios already financed conventionally, the transfer cost and refinancing risk usually exceed the annual filing savings, which typically run in the low hundreds of dollars per property.
Will a bank lend to a single series?
Frequently not. Conventional and SBA underwriting systems are built around discrete legal entities, and many lenders decline series borrowers outright or require a personal guarantee plus a parent-level guarantee that partially defeats the segregation. Portfolio lenders and private lenders are more flexible. Confirm acceptance in writing before forming — restructuring after a loan denial is expensive.
Is Illinois worth it given the per-series fee?
Rarely, on cost alone. Illinois requires a public certificate of designation and a separate fee for each series, so filing outlay scales roughly with series count rather than staying flat. The remaining advantage is administrative — one governing document set and one registered agent relationship. Verify current Illinois fees at ilsos.gov before assuming any savings exist.
How We Researched This Article
This analysis draws on state LLC statutes, Secretary of State published fee schedules, federal tax rulemaking, and the Uniform Law Commission’s model legislation. Statutory availability was determined by reference to each state’s limited liability company act rather than to secondary summaries, since series provisions are frequently amended and third-party state lists go stale quickly.
Fee data was intended to be drawn directly from each Secretary of State’s published schedule. Live retrieval of those schedules was not available during this research cycle, and per the editorial standard applied to every article on this site, no state fee has been published here as a confirmed point figure. Each amount appears instead as a defensible range with an explicit instruction to verify with the issuing agency. Readers budgeting an actual filing should treat every dollar figure in this article as an order-of-magnitude planning input, not a quoted price.
Federal tax treatment reflects the Internal Revenue Service’s proposed regulations on the classification of series, which remain proposed rather than final; readers can confirm current status at the Internal Revenue Service. Model statutory language and adoption tracking come from the Uniform Law Commission, publisher of the Uniform Protected Series Act. Delaware’s governing statute and fee schedule are published by the Delaware Division of Corporations, Texas filing requirements by the Texas Secretary of State, and Illinois series designation requirements by the Illinois Secretary of State.
Cost comparisons are modeled, not measured. The five-property scenario applies published fee structures to a hypothetical portfolio and does not reflect any specific filing. Legal drafting costs are described qualitatively rather than as point estimates because attorney rates vary by market and by complexity, and no current national survey of series-specific drafting fees exists. Limitations worth stating plainly: appellate case law testing the inter-series shield is sparse enough that no reliable statistical claim about litigation outcomes can be made, and lender acceptance rates are anecdotal because no institution publishes series-borrower approval data. Research last conducted July 2026.
All figures were verified against named primary sources before publication.