Guam taxes businesses on a "mirror" code, which sounds unusual until you see it in practice: federal-style income tax brackets apply almost exactly as they do stateside, except you file and pay locally to Guam's own Department of Revenue and Taxation rather than the IRS. Layered on top is a monthly Gross Receipts Tax that hits revenue rather than profit, which changes the math for a lot of new businesses used to mainland rules. This covers what forming and running a business on Guam actually involves in 2026.
1. Which business structure fits you?
Guam narrows the choice down to two structures for most founders.
- LLC. Comes with personal liability protection, flexible internal management, and pass-through taxation as the default, though electing corporate-style taxation is also an option. Filing Articles of Organization costs $250.
- Corporation. A separate legal entity with more formal governance obligations attached, generally the better fit if you're planning to raise capital or add multiple shareholders down the line.
2. Register your business
Formation documents — Articles of Organization for an LLC, Articles of Incorporation for a corporation — get filed with Guam's Department of Revenue and Taxation. One thing that catches people off guard: limited liability entities on Guam are required to publish a formation notice in two newspapers and then submit a certificate of publication within a 120-day window, and skipping this can suspend your authority to do business. Separately, every business on Guam, sole proprietors included, needs a general business license from the DRT's General Licensing and Registration Branch. The fee typically falls between $100 and $1,000, scaled to your annual gross income, and it renews every year by June 30.
3. Understand the Gross Receipts Tax
The Gross Receipts Tax, or GRT, is the tax that defines doing business on Guam: a flat 5% on gross income rather than net profit, filed and paid monthly, with online filing as the only option. Because it doesn't care what your margins look like, it's smart to bake this into your pricing from the start rather than discover it later.
4. Check licenses and permits
On top of the general business license, a handful of professions — CPAs, doctors, attorneys — carry their own specialized licensing requirements. A foreign corporation needs both a business license and a Certificate of Authority from the DRT before it can transact business on Guam.
5. Understand Guam's income tax
Guam's mirror-code system means corporate and individual income tax brackets track federal rates closely, with the distinction being where the check goes: Guam's Department of Revenue and Taxation, not the IRS.
6. Stay compliant
LLCs and corporations alike file a Sworn Annual Report between July 1 and September 1 each year, beginning the year after formation, and the fee is $100; corporations also report their authorized shares, class, and par value in that filing. Falling more than 60 days past the deadline adds a $50 late fee.
Guam business costs at a glance
| Item | Cost |
|---|---|
| LLC Articles of Organization | $250 |
| General business license (annual) | $100 to $1,000 |
| Gross Receipts Tax (monthly, on gross income) | 5% |
| Sworn Annual Report | $100/year |
| Late Sworn Annual Report fee | $50 |
Frequently asked questions
What is Guam's Gross Receipts Tax?
It's a flat 5% charged on gross income rather than net profit, filed monthly, and it applies no matter how thin your margins run.
Does Guam use a mirror tax code?
It does — federal-style income tax brackets apply, but the payment goes to Guam's own Department of Revenue and Taxation instead of the IRS.
How much does it cost to form an LLC in Guam?
Articles of Organization cost $250, and then there's a general business license running $100 to $1,000 a year depending on gross income.
Does Guam require a newspaper publication notice?
Yes — limited liability entities must publish a formation notice in two newspapers and file a certificate of publication within 120 days.
When is Guam's Sworn Annual Report due?
Every year between July 1 and September 1, starting the year following formation, at a cost of $100.
Fees and rates above come from Guam's Department of Revenue and Taxation as of 2026, and they do change over time, so double check before you file. None of this is legal or tax advice. Talk to a Guam-qualified accountant or lawyer about your specific situation.