You cannot form a Colorado series LLC. The state’s LLC statute does not authorize series or protected series structures, and a 2020 bill that would have changed that died in committee. If you want to use the structure while doing business in Colorado, you form the series LLC in a state that allows them, such as Delaware, Nevada, Wyoming, Illinois, or Texas, and then register each operating series as a foreign entity with the Colorado Secretary of State for $100 per filing. The harder question is whether a Colorado court will honor the internal liability walls between your series, because no statute and no published case law says it will.
Why Colorado Doesn’t Allow Series LLCs
Colorado’s LLC law sits in Title 7, Article 80 of the Revised Statutes. Nothing in that article addresses series or protected series.1Justia. Colorado Code – Limited Liability Companies House Bill 20-1096 would have enacted the Uniform Protected Series Act, giving Colorado business owners both horizontal shields between series and vertical shields between the master LLC and its series. The House Judiciary Committee postponed the bill indefinitely, and no replacement has advanced since.2Colorado General Assembly. HB20-1096 Authorize Protected Series Of Limited Liability Co
So Colorado treats the series LLC the way it treats any other out-of-state entity: you can’t create one here, but you can bring one in after forming it somewhere that does authorize it.
Registering a Foreign Series LLC in Colorado
Any foreign entity transacting business in Colorado must first file a Statement of Foreign Entity Authority with the Secretary of State.3Justia. Colorado Code 7-90-801 – Authority to Transact Business or Conduct Activities Required The filing is online, the fee is $100, and approval is usually immediate. You can download a Certificate of Fact at no extra charge once the filing is accepted.4Colorado Secretary of State. Business Organizations Fee Schedule
The filing asks for the entity’s exact legal name as registered in the formation state (including the LLC designator), the jurisdiction where you formed it, a Colorado registered agent with a physical in-state street address, the principal office address, and the date you intend to start doing business here.5Colorado Secretary of State. Statement of Foreign Entity Authority As of July 1, 2025, individual registered agents must hold a valid Colorado driver’s license or ID, or verify residency with the Secretary of State’s office.6Colorado Secretary of State. Registered Agent Requirements Effective July 1, 2025
Do You Register the Master LLC, Each Series, or Both?
Colorado has no specialized registration pathway for series entities. Unlike Illinois or Virginia, which offer a separate Certificate of Designation for individual series, Colorado’s foreign filing system assumes a standard LLC. As a practical matter, if multiple series will each hold property, sign contracts, or operate businesses in Colorado, each series should file its own Statement of Foreign Entity Authority. Registering only the master LLC and operating everything under that single filing gives a future creditor a strong argument that the series are not actually distinct for Colorado purposes. Each separate filing is another $100.
Activities That Don’t Require Registration
Colorado law lists activities that don’t count as transacting business, so a series doing only those things doesn’t have to file. The safe harbor covers owning Colorado real estate without actively managing it, maintaining bank accounts, holding internal meetings, and collecting debts.3Justia. Colorado Code 7-90-801 – Authority to Transact Business or Conduct Activities Required A series that passively holds a rental managed entirely by a third-party property manager may fall inside it. Once that series starts signing leases directly, hiring contractors, or dealing with tenants, it has crossed the line.
Will Colorado Courts Honor the Series Shields?
This is the question that decides whether a series LLC is worth doing for Colorado operations. The honest answer is that nobody knows.
Colorado’s foreign entity law says that the laws of the formation state govern a foreign LLC’s organization and internal affairs and the liability of its members and managers. That language protects you personally as an LLC member the same way it would with any standard foreign LLC. The internal liability walls between series are a different question. Those shields limit the liabilities of subdivisions inside the entity itself, not the personal liability of owners, and Colorado’s foreign recognition provisions were not written with series structures in mind. A Colorado court could read formation-state deference broadly and respect the walls. It could also apply Colorado’s own creditor rules and treat the master LLC’s assets as one pool regardless of internal compartments. There is no published Colorado case on the question.
If you are using the structure to isolate high-value or high-risk assets from each other, you are betting that a judge who has never seen the issue will rule your way on an untested theory. For small portfolios or low-litigation businesses, that bet may be acceptable. For significant real estate holdings or businesses with real liability exposure, forming separate standalone LLCs costs more but gives you clean, settled Colorado law behind each wall.
Ongoing Cost and Compliance
Registration is not a one-time event. Each foreign entity authorized in Colorado must file an annual Periodic Report with the Secretary of State at $25 per filing.7Colorado Secretary of State. Periodic Reports4Colorado Secretary of State. Business Organizations Fee Schedule Five registered series means five reports and $125 a year in Colorado reporting fees, on top of whatever the formation state charges.
Each entity has its own reporting month, shown on its Summary page in the filing system. The window runs two months before the due date and two months after. Miss it and the entity’s status moves to “Noncompliant” and then “Delinquent.”8Colorado Secretary of State. Delinquency
Delinquency costs you good standing. After 400 days, the Secretary of State releases your entity name for others to claim and attaches “delinquent” to the record.8Colorado Secretary of State. Delinquency Curing it requires a Statement Curing Delinquency at $100 per entity.4Colorado Secretary of State. Business Organizations Fee Schedule After five years of delinquency, you also need an affidavit under penalty of perjury and a government photo ID proving you have authority to act for the entity.
Keep the registered agent current. If your agent resigns and you don’t name a replacement, that alone triggers delinquency.8Colorado Secretary of State. Delinquency A professional registered agent service generally runs roughly $35 to $200 per entity per year, and that multiplies across every series you register.
What Happens If You Skip Registration
A foreign entity transacting business in Colorado without authority cannot bring a lawsuit in any Colorado court to collect debts or enforce contracts until it registers.9Justia. Colorado Code 7-90-802 – Consequences of Transacting Business or Conducting Activities Without Authority If a tenant stops paying or a counterparty breaches, your series is locked out of court until it files and pays all back fees.
The state can also impose a fee of up to $100 for each calendar year you operated without authority plus a civil penalty of up to $5,000. The Colorado Attorney General can bring an enforcement action and obtain an injunction barring the entity from any further Colorado business until all fees, penalties, interest, and court costs are paid.9Justia. Colorado Code 7-90-802 – Consequences of Transacting Business or Conducting Activities Without Authority Contracts you have already signed stay valid, and you can still defend yourself if someone sues you. The handicap is that you can’t bring your own claims.
Running the Structure So the Shields Have a Chance
The liability walls exist on paper. Whether they hold up depends on whether you actually treat each series as its own operating unit. Courts in states that do have series statutes have been clear that commingling funds or blurring the lines between series lets creditors argue the walls are a fiction. In Colorado, which has no series framework of its own, sloppy records give a judge an easy reason to disregard the structure entirely.
Give each series its own dedicated bank account, titled in the series name exactly as registered. Run all income and expenses for that series through that account and nowhere else. If Series B needs money from Series A, paper it as a loan with written terms, not a casual transfer. Keep separate ledgers or at least a chart of accounts that tracks each series independently.
Operating agreements need the same discipline. Each series should have its own operating agreement, or a detailed supplement to the master agreement that spells out that series’ members, ownership percentages, assets, and management authority. When a series signs a contract, the signature block names that specific series. Signing as just the master LLC defeats the point.
Keep minutes for decisions affecting individual series. Record asset transfers in writing. Sale proceeds from a property owned by a series go back into that series’ account. The required discipline is close to what you would do running several separate LLCs, which is part of why the administrative savings of a series structure are often smaller than advertised.
Series LLC or Separate LLCs for Colorado Operations?
The pitch for a series LLC is one entity, one set of formation fees, one tax return, and the isolation of many LLCs. In the formation state, that pitch holds up well for someone running ten rentals: you avoid ten formations, ten annual reports, and potentially ten returns.
The pitch weakens the moment you operate in Colorado. Each series you register here costs the same $100 initial filing and $25 annual report as a standalone foreign LLC. You still need separate bank accounts, separate books, and separate operating agreements. You also carry the shield uncertainty described above.
Standalone LLCs give you one clean advantage: the liability protection of a single-member or multi-member LLC is settled Colorado law, with no novel question for a judge to answer. The trade-off is higher formation and maintenance costs. For a portfolio of two or three properties, separate LLCs are often cheaper and simpler once Colorado registration costs are counted. For larger portfolios where the formation-state savings are real, the series structure can still make sense if you accept the shield risk or if your main liability exposure sits in the formation state rather than here.