California: Assumed-Name (DBA) Registration Requirements

Requirements one by one

Who must register

The duty falls on anyone who "regularly transacts business in this state for
profit under a fictitious business name" (§ 17910). Whether a name is
"fictitious" depends on who you are (§ 17900):

• A sole proprietor needs a filing whenever the business name leaves out
  their surname or hints at other owners. "Maria Chen" doing business as "Chen
  Accounting" needs one (no first name is not the issue — the statute keys on the
  surname and on words like "Company," "& Associates," or "Brothers" that
  "suggest the existence of additional owners"). "Maria Chen, Bookkeeper" does
  not.
• A general partnership needs one unless the name includes the surname of
  every general partner.
• An LLC or corporation needs one for "any name other than" the exact name on
  file with the California Secretary of State. An LLC operating under its full
  registered name files nothing (see What trips people up).

Only for-profit business triggers the chapter.

Where and when to file

You file the fictitious business name statement with "the clerk of the county in
which the registrant has his or her principal place of business" (§ 17915). If
your business has no California location, you file with the Clerk of Sacramento
County. The deadline is "not later than 40 days from the time the registrant
commences to transact" business under the name (§ 17910(a)) — counted from when
you start using the name, not from when you form the entity.

The newspaper-publication step

After filing, you must publish the statement. Section 17917 gives you 45 days
from filing to run it "in a newspaper of general circulation in the county where
the fictitious business name statement was filed," and the publication itself
follows Government Code § 6064: "once a week for four successive weeks." Within
45 days after the last insertion, you file the newspaper's affidavit of
publication with the same county clerk. If there is no qualifying newspaper in
your county, you publish in an adjoining county; if you have no California
business location, you publish in Sacramento County.

How long it lasts

A statement "expires five years from the date it was filed" (§ 17920(a)). To
keep using the name, you refile before it lapses. Two events end it sooner: a
change in the facts on the statement (it expires 40 days after the change, with
a narrow partnership-withdrawal exception under § 17923), and filing a statement
of abandonment.

What happens if you skip it

California does not fine you for merely operating unregistered; instead it shuts
the courthouse. Until the statement "has been executed, filed, and published,"
you "may [not] maintain any action upon or on account of any contract made" in
the fictitious name (§ 17918). Separately, knowingly filing or publishing a
false statement "shall be guilty of a misdemeanor" punishable "by a fine not to
exceed one thousand dollars ($1,000)" (§ 17930).

What trips people up

• An entity using its exact legal name files nothing. The chapter only
  reaches a name "other than" the one registered with the Secretary of State
  (§ 17900). "Blue Oak Design LLC" operating as "Blue Oak Design LLC" has no DBA;
  the same LLC operating as "Blue Oak Studio" does.
• The suit-bar is a delay, not a death sentence. If you sued and then
  discovered you never filed, § 17918 blocks the case — but it is curable. You
  file and publish, and you can proceed; the underlying contract stays valid.
  The lesson is to file before you need to enforce anything, because a defendant
  will raise the bar at the worst moment.
• A change in the facts quietly expires your statement. A new business
  address or a change in ownership expires the statement 40 days after the
  change (§ 17920(b)) — long before the five-year mark — so update it when
  anything on it changes.
• Registering does not lock up the name. The filing is "not intended to
  confer any right or advantage" and only makes owners' identities public
  (§ 17900(a)). Another business can file the same name in another county, and a
  prior trademark holder can still stop you. Brand protection is a trademark
  question.

Common questions

Do I need a DBA to open a business bank account? The law does not say so, but
banks routinely require the filed statement (and often the published copy)
before opening an account in the business name. Filing early avoids that holdup.

I run my business from home in one county but sell across California — where do
I file? With the clerk of the county of your principal place of business
(§ 17915). You may also file in other counties, but the home-county filing is
the required one.

Does filing stop a competitor from using my name? No. Registration is public
notice only (§ 17900(a)). To keep others from using a brand name, look at state
or federal trademark registration, which is a separate process.

How much does it cost? The chapter sets no state fee. The county clerk
charges its own filing fee, which varies by county, and you separately pay the
newspaper that runs your four-week publication. Budget for both.

Statutes and sources

• Cal. Bus. & Prof. Code § 17900 — defines "fictitious business name" by
  entity type and states the public-notice purpose. Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17910 — duty to file within 40 days of commencing
  business. Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17915 — filing with the county clerk of the
  principal place of business, or Sacramento County. Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17917 — 45-day publication window and affidavit.
  Official text (accessed 2026-07-23).
• Cal. Gov. Code § 6064 — "once a week for four successive weeks." Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17918 — suit-bar until filed and published.
  Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17920 — five-year term and early-expiration
  triggers. Official text (accessed 2026-07-23).
• Cal. Bus. & Prof. Code § 17930 — misdemeanor for a knowingly false
  statement. Official text (accessed 2026-07-23).