A Delaware Series LLC is a single limited liability company that uses Delaware’s LLC Act to create internal divisions, called series, each with its own assets, members, and liabilities, without forming a separate legal entity for each one. The structure is common for real estate portfolios, investment funds, and businesses running distinct product lines, because it can cut formation and maintenance costs compared with setting up a separate LLC for every venture. What you actually get, how much it costs, and how well the liability walls hold up all depend on choices you make at formation.
How the Internal Liability Shield Works
The structure begins with one parent LLC, sometimes called the master LLC. That parent creates individual series through its operating agreement, and each series can hold its own property, take on its own debts, and operate with its own members or managers. Someone assigned to one series has no automatic stake or authority in another series under the same parent.
The core feature is internal liability separation. When the structure is properly maintained, the debts and obligations of one series can be enforced only against that series’ assets, not against the parent LLC’s general assets or any other series. A claim against Series A shouldn’t reach the real estate held by Series B. That “shouldn’t” is doing real work in that sentence: the separation holds only if you keep the paperwork and records the statute requires.
Protected Series or Registered Series
Delaware gives you two ways to create these internal divisions, and the practical differences matter more than most formation guides suggest.
Protected Series
A protected series is created entirely through the operating agreement. No separate state filing is required for each individual series. The parent LLC’s certificate of formation must include a notice that the company has series with limited liability, but beyond that, individual protected series stay private and don’t appear in any state database.
That privacy comes with trade-offs. A protected series cannot obtain its own certificate of good standing from the Delaware Secretary of State, which makes it harder to open bank accounts, secure financing, or satisfy third-party due diligence. A protected series also does not qualify as a “registered organization” under the Uniform Commercial Code, which complicates secured lending against a specific series’ assets. Protected series are not subject to Delaware’s annual series tax.
Registered Series
A registered series requires filing a Certificate of Registered Series with the Delaware Division of Corporations. The filing fee is $110. Each registered series must have a name that starts with the parent LLC’s name and is distinguishable from every other entity name on file with the state.
In exchange, a registered series can obtain its own certificate of good standing, qualifies as a registered organization under the UCC for secured-transaction purposes, and appears in state records. If a series needs to borrow money, hold titled property, or deal with counterparties who require official state verification, registered is the way to go. The cost is a $75 annual tax per registered series on top of the parent LLC’s own annual tax.
Converting Between the Two
Delaware allows conversion in either direction. To convert a protected series into a registered series, you file two documents at the same time with the Secretary of State: a certificate of conversion and a certificate of registered series. The certificate of conversion must identify the parent LLC, the original protected series name, the new registered series name, the date the protected series was established, and a statement that the conversion was properly approved. The conversion certificate costs $180, plus the $110 for the new certificate of registered series.
What Goes in the Certificate of Formation
The certificate of formation creates the parent LLC. Under 6 Del. C. § 18-201, the certificate must include the LLC’s name (which must contain “Limited Liability Company,” “L.L.C.,” or “LLC”), the street address of its registered office in Delaware, and the name and address of its registered agent for service of process.
For a series LLC, the certificate must also include a notice that the company’s debts and obligations attributable to one series are enforceable only against that series’ assets. This notice activates the liability shield under 6 Del. C. § 18-215(b). Without it, you have a regular LLC with some internal bookkeeping divisions and no statutory liability separation between them. The Delaware Division of Corporations provides fillable templates with a designated field for this language.
What the Operating Agreement Has to Cover
The operating agreement is where the series structure actually lives. For a protected series, it is the only document that creates the series at all. Even for registered series, the operating agreement governs day-to-day operations. At a minimum, a series LLC operating agreement should address:
- Liability limitation language stating clearly that no debt or obligation of one series is enforceable against any other series or against the parent LLC’s general assets, mirroring the notice in the certificate of formation.
- An affirmative obligation to maintain distinct records and accounts for each series, with assets held and tracked separately.
- Which members and managers are associated with each series, and their rights and authority. A member of one series has no automatic voting power or profit interest in another.
- The events that will cause a specific series to dissolve, and who has authority to wind up its affairs.
- Indemnification obligations payable only from the assets of the relevant series, not from the parent or other series.
A boilerplate single-member LLC agreement will not do the job. The operating agreement has to address the multi-series structure explicitly, or you’re building liability walls on paper while leaving the doors unlocked.
Record-Keeping That Actually Holds the Shield
The wall between series only holds if you maintain it. Delaware’s statute is explicit: records for each series must account for that series’ assets separately from the parent LLC’s general assets and from every other series. Let the bookkeeping slide and the entire liability shield is at risk.
The statute is flexible about how you track assets. Records can identify a series’ assets by specific listing, by category or type, by a percentage allocation formula, or by any other method that makes the assets “objectively determinable.” What the statute will not tolerate is ambiguity. If a creditor or court can’t tell which assets belong to which series, the separation fails.
In practice, this means each series should have its own bank account, its own ledger, and its own contracts. Commingling funds across series is the fastest way to lose the very protection the structure was designed to provide.
Filing Fees and Processing Speed
The standard filing fee for a Certificate of Formation is $110, which includes the $70 statutory filing fee and a $40 municipality fee. A Certificate of Registered Series costs the same $110. Conversion from protected to registered costs $180 for the conversion certificate plus $110 for the new registered series certificate.
Delaware offers several processing speeds on top of the base fee:
- Standard processing is included in the base filing fee, with processing time varying.
- 24-hour service adds $100.
- Same-day service adds $200.
- Priority 2 (two-hour) service adds $500.
- Priority 1 (one-hour) service adds $1,000.
Filings can be submitted through the Delaware Global Connected portal (eCorp) or sent by mail or fax. Every submission must include a filing memo and the appropriate payment.
Annual Delaware Tax
Every Delaware LLC owes a $300 annual tax, due June 1. That applies to the parent series LLC no matter how many series it contains. Each registered series owes an additional $75 annual tax, also due June 1. Protected series trigger no additional annual tax.
The math adds up fast. A parent LLC with ten registered series pays $300 plus $750 in series taxes, or $1,050 a year in Delaware annual taxes alone. The same structure using protected series would owe only the $300 parent tax. That gap is one reason many series LLC owners default to protected series unless they need the registered form’s certificate of good standing or UCC status.
Federal Tax Treatment Is Unsettled
Federal tax classification for series LLCs is still not fully resolved. The IRS published proposed regulations in 2010 stating that each domestic series should be treated as a separate entity for federal tax purposes, with classification determined under the standard entity-classification rules: a single-member series would default to a disregarded entity, a multi-member series would default to a partnership, and any series could elect corporate taxation using Form 8832.
Those proposed regulations have never been finalized. In practice, most tax professionals treat each series as a separate entity consistent with the proposed rules, but the lack of final guidance creates real uncertainty. The IRS has not issued clear rules on whether each series needs its own Employer Identification Number. The conservative approach is to obtain a separate EIN for any series that has its own employees, files its own tax return, or opens its own bank account. Talk to a tax professional familiar with series LLC structures before filing; getting this wrong can be expensive to unwind.
Doing Business Outside Delaware
This is where the elegant structure runs into friction. Roughly 20 jurisdictions have enacted their own series LLC statutes, including Delaware, Illinois, Texas, Nevada, and Wyoming. The rest have no series LLC legislation, and the open question is whether courts in those states will respect the internal liability shields of a series formed in Delaware.
The honest answer is that nobody knows for certain. Series LLCs have not been widely tested in litigation, and courts in states without series statutes have little reason to defer to Delaware’s framework when a dispute arises in their own jurisdiction. California, for example, allows a Delaware series LLC to register as a foreign entity but provides no statutory basis for enforcing the liability separation between series. Other states have no framework for series LLCs at all.
If your series LLC will operate only in Delaware or another state with its own series statute, this risk is manageable. If you plan to do business across multiple states, especially states without series legislation, weigh whether separate LLCs would provide more reliable liability protection despite the higher formation and maintenance costs. Savings from a series structure mean little if a court in another state collapses the walls when it matters most.
Dissolving a Single Series
One advantage of the structure is that you can wind down a single series without touching the parent LLC or any other series. A series dissolves on the first of several events: the time or event specified in the operating agreement, a vote of members holding more than two-thirds of the profits interest in that series, or a decree from the Delaware Court of Chancery when continuing the series’ business is no longer reasonably practicable.
Unless the operating agreement says otherwise, winding up is handled by a manager associated with the series who did not wrongfully cause the dissolution. If no such manager exists, members owning more than half the profits interest in the series can appoint someone. The person winding up must settle the series’ debts and distribute remaining assets under the statutory priority rules.
Registered series have one extra step: after winding up is complete, you file a certificate of cancellation with the Secretary of State. That certificate identifies the parent LLC, the registered series name, and the date of the original certificate of registered series. The filing fee is $180. Protected series, never separately filed, require no state filing to dissolve; the operating agreement governs the entire process.