Residency Migration Reference
Moving from Colorado to Guam: Residency, Taxes, and What to Prove
Colorado's 4.40% top income tax rate becomes 37% under the mirrored federal brackets; as low as roughly 25% of that (a 75% reduction) for up to 20 years for approved GEDA Qualifying Certificate holders in Guam. This move trades a lighter tax environment for a heavier one, so timing income around the transition year matters.
Residency Tests Side by Side
Colorado does not use a simple day-count threshold; it applies a facts-and-circumstances test instead. Guam's statutory residency test uses a 183-day threshold.
| Factor | Colorado | Guam |
|---|---|---|
| Statutory Residency Test | Under Colorado Department of Revenue Rule 39-22-103(8)(a), a natural person is a Colorado resident if either domiciled in Colorado or the person satisfies the six-month rule: maintaining a permanent place of abode in Colorado and spending, in the aggregate, more than six months of the tax year in Colorado. A permanent place of abode is any place a person has a possessory right to live, including a leased apartment or an employer-paid apartment the person actually pays for and returns to on days off; a motel room or an RV camp lot without hookups generally does not qualify. | Guam, like the other four territories, has no day-count statutory residency overlay of its own. Bona fide residency is governed by the federal IRC section 937 three-part test: the presence test, the tax home test, and the closer connection test, all of which must be satisfied for the same tax year. DRT applies the identical federal standard used by the IRS. |
| Domicile Test | Colorado's domicile rule defines domicile as a place of abode combined with the present intention of returning after any absence, regardless of how long the absence lasts. A person can have only one domicile at a time (with a narrow exception for genuine seasonal dual-domicile arrangements), domicile continues until affirmatively changed, and the burden of proving a change rests on the person asserting it. The regulation lists 18 non-exclusive indicia the Department weighs, including prior domicile, length of time in the new place, spouse/dependent location, driver's license and vehicle registration jurisdiction, voter registration, employment location, government benefits received, mailing address for financial documents, professional licenses, prior-year filing positions, and even social media statements of residency; no single factor controls. | Closer connection functions as Guam's domicile test under Treasury Regulation 1.937-1(c): the location of a permanent home, family, personal belongings, social/political/cultural/religious affiliations, routine banking, business activity, and the jurisdiction of a driver's license and voter registration are weighed against the total of U.S. and foreign-country contacts. Publication 570's own illustrative example uses a Guam/CNMI fact pattern (a hotel employee who splits time between the two) to show how the tax home and closer connection tests interact when someone has ties to more than one territory. |
| Day Count Threshold | No fixed threshold | 183 days |
| Any Part of a Day Rule | The regulation text sets the threshold as 'more than six months' rather than a codified exact day count, so practitioners generally treat it as 183-plus days. The published rule does not spell out an explicit any-part-of-a-day counting convention the way New York's does; absent that guidance, taxpayers close to the line should assume any day with Colorado presence could be counted and keep contemporaneous records. | Any part of a day physically present in Guam counts as a full presence day, and a day spent in both Guam and the mainland U.S. counts toward Guam. The standard exceptions for qualified medical treatment, presidentially declared disasters, mandatory evacuations, and a limited 30-day travel allowance apply under the Form 8898 instructions. |
| Presumptions | The place where a person currently lives is presumed to be their current domicile, and once domicile is established it is presumed to continue. Spouses are presumed to share a domicile until separated. A person who lives in a motorhome and owns no real property elsewhere is treated as a full-year Colorado domiciliary if their permanent ties are here and they spend more aggregate time in Colorado than anywhere else; conversely, someone who owns a home in another state but travels to Colorado seasonally is not treated as a Colorado domiciliary absent other factors. | None published |
| Safe Harbors | None published | 183-day presence test; 549-day / 3-year test; 90-day U.S. cap; Low U.S.-earned-income test; No significant U.S. connection |
Leaving Colorado
Colorado does not have the reputation or enforcement infrastructure of California, New York, or the other states named repeatedly in practitioner and taxpayer discussions (California, New York, New Jersey, Connecticut, Maryland, Minnesota) as aggressive residency-audit states. The Department's own domicile regulation is unusually detailed and taxpayer-facing, which suggests the state has litigated or ruled on enough close cases to want the factor list written down, but there is no publicly documented pattern of large-scale departing-resident sweeps comparable to California's FTB program. The people most likely to draw scrutiny are those who keep a Colorado home, spouse, or dependents in place while claiming to have moved, or who cross the six-month permanent-place-of-abode threshold while still filing as a nonresident.
Trailing Income
Colorado-source income, such as income from Colorado real property, a Colorado business, or Colorado-performed services, continues to be taxed to nonresidents after departure via the DR 0104PN nonresident computation. Colorado has no state-specific convenience-of-employer rule reaching remote workers who have genuinely left, and deferred compensation from qualifying retirement plans generally follows the federal 4 U.S.C. §114 rule reserving taxation to the state of residence at the time each payment is received.
Part-Year Filing
Form DR 0104, the Colorado Individual Income Tax Return, filed together with the DR 0104PN, Part-Year Resident/Nonresident Tax Calculation Schedule, which prorates tax so it applies only to income received while a Colorado resident plus any Colorado-source income earned before arriving or after leaving.
Enforcement Methods
Common Exit Mistakes
Establishing Guam Residency
| Action | Agency | Deadline |
|---|---|---|
| Get a Guam driver's license | Department of Revenue and Taxation, Motor Vehicle Division | no published fixed deadline for new residents |
| Register to vote | Guam Election Commission (GEC) | in-person registration deadline is 10 business days before an election; register ahead of any election you intend to vote in |
| Apply for a GEDA Qualifying Certificate (business owners/investors seeking tax abatement) | Guam Economic Development Authority (GEDA) | application and approval precede any benefit; ongoing investment/employment commitments must be maintained for the certificate term |
| File Form 1040GU as a bona fide resident | Department of Revenue and Taxation, Taxpayer Services Division | April 15, calendar-year filers |
Declaration of Domicile
Guam has no standalone sworn declaration-of-domicile filing. Bona fide residency is established through the same federal section 937 factual record used across the territories: a Guam driver's license, Guam voter registration, Guam banking, and, where applicable, GEDA Qualifying Certificate compliance records showing genuine local business operations.
Homestead
Guam does not have a distinct homestead exemption program comparable to Florida's or Puerto Rico's CRIM exemption; the territory's advantage is instead its low baseline real property tax rate (roughly 0.5% to 1% of assessed value), and Qualifying Certificate holders can receive a full real property tax exemption on an approved project for up to 10 years.
Voter Registration
Register at the Guam Election Commission office, through a volunteer registrar, at a village mayor's office, or online through the GEC portal: https://gec.guam.gov/register/. In-person registration must generally be completed at least 10 business days before an election.
Vehicle Registration Deadline
null days
New Resident Tax Traps
The most common trap is treating Qualifying Certificate approval as self-executing rather than a benefit that depends on maintaining real, ongoing investment and employment commitments plus genuine bona fide residency; GEDA and DRT can review compliance throughout the certificate term, not just at approval. A second trap, highlighted in Publication 570's own worked example, is splitting time between Guam and the CNMI without a clear tax home, which can jeopardize the closer connection analysis for both territories at once.
What Changes on Tax
Colorado Top Rate
4.40%
Guam Top Rate
37% under the mirrored federal brackets; as low as roughly 25% of that (a 75% reduction) for up to 20 years for approved GEDA Qualifying Certificate holders
Moving from Colorado to Guam raises the top marginal income tax rate from about 4.4% to about 75%, an increase of roughly 70.6 percentage points.
Withholding Reciprocity
Colorado and Guam do not have a wage-withholding reciprocity agreement with each other, so this move follows ordinary source-state and resident-state filing rules rather than a reciprocity exception.
Community Property Transition
Colorado and Guam both use common law, equitable-distribution marital property rules, so no community property transition applies to this move.
Beyond Income Tax
Colorado
Capital gains: Taxed as ordinary income at the flat 4.40% rate. Colorado once allowed a broad $100,000 capital gain subtraction for qualifying property held five-plus years, but for tax years commencing on or after January 1, 2022 that subtraction was narrowed to apply only to capital gains recognized by farmers who file federal Schedule F on the sale of agricultural real property. Nearly everyone else pays the full flat rate on gains.
Estate or inheritance tax: None. Colorado has no estate tax and no inheritance tax.
Property tax: Effective rate is roughly 0.50% of value, among the lowest in the country. Colorado's Senior Property Tax Exemption is a targeted homestead-style break, not a general portability system: it exempts 50% of the first $200,000 of actual value for owners 65 and older who have owned and occupied the home for at least 10 consecutive years, funded by state reimbursement to counties when the legislature appropriates it.
Sales tax: 2.90% state rate, with average combined state-and-local rates around 7.89% once city, county, and special-district taxes are layered on.
Guam
Capital gains: Capital gains follow the same rates as the mirrored federal code; there is no separate Guam capital gains schedule. A Qualifying Certificate from the Guam Economic Development Authority (GEDA) can reduce the effective tax rate, including on qualifying business-related gains, for an approved project.
Estate or inheritance tax: Guam has no separate territorial estate or inheritance tax; federal estate tax rules apply through the mirror code framework to Guam-domiciled decedents, administered locally by DRT rather than the IRS.
Property tax: Real property tax rates run roughly 0.5% to 1% of assessed value annually, among the lowest effective property tax burdens under the U.S. flag, and Qualifying Certificate holders can receive a full real property tax exemption for up to 10 years on an approved project.
Sales tax: Guam has no general retail sales tax. Instead it imposes a 5% Business Privilege Tax (BPT, Guam's gross receipts tax) on businesses and a matching 5% use tax on imported personal goods, both of which GEDA Qualifying Certificate holders can have substantially abated.
Who This Move Applies To
Travel Nurses
In Colorado
Denver, Colorado Springs, and the Front Range hospital systems make Colorado a significant travel-nurse market. A nurse whose actual domicile is Colorado and who takes Colorado contracts is simply taxed as a resident. A nurse who claims a Colorado tax home while working assignments in other states needs a genuine, regularly used, duplicated-expense Colorado residence; the same indicia list the Department applies to ordinary domicile disputes (driver's license, voter registration, time actually spent) applies to a nurse's claimed tax home, and a thin paper trail risks the same stipend-to-wages reclassification travel nurses face in every state.
In Guam
Guam is not a major travel-nurse assignment market compared to the 50 states, but Guam Memorial Hospital and private facilities do draw contract clinical staff; the underlying federal tax-home analysis is identical to any state, requiring genuine maintenance of and return to a Guam home between assignments to sustain a Guam tax-home claim.
Professional Athletes
In Colorado
Colorado is home to the Broncos, Nuggets, Rockies, and Avalanche, and nonresident athletes on visiting teams owe Colorado tax on the duty days they spend in the state under standard apportionment against total season duty days. Because Colorado's rate is a flat 4.40% with no separate capital-gains carve-out, the jock-tax math is simpler than in graduated-rate states, but the liability is real and applies to every visiting team that plays a game in Denver.
In Guam
No major U.S. professional sports franchise is based in Guam, so there is no home-team jock-tax apportionment regime specific to the territory. Visiting athletes or performers earning income from events physically held in Guam owe Guam-source tax on income attributable to that work under the mirrored federal withholding framework administered by DRT.
Snowbirds, Long Visitors, and RVers
In Colorado
Colorado's scenario runs in both directions. Wealthy buyers in Aspen, Vail, Telluride, and other mountain resort towns who keep a primary domicile elsewhere need to track aggregate days against the six-month, permanent-place-of-abode threshold, since a leased or owned ski home plainly qualifies as a permanent place of abode. Separately, Colorado's own domiciliaries who spend winters in Arizona or Florida remain presumed Colorado domiciliaries under the regulation's continuing-domicile presumption unless they affirmatively establish a new domicile elsewhere, so simply wintering out of state does not by itself cut Colorado ties.
In Guam
A mainland resident who buys a Guam property and spends significant time there while keeping a permanent mainland home risks failing the closer connection test even with a solid day count, unless family, banking, and business ties also shift to Guam. Publication 570's own example addresses a related pattern directly: someone with ties to both Guam and the CNMI must determine which is the actual tax home based on where their regular place of business is located, not simply where they own property.
Remote Workers
In Colorado
Colorado has no convenience-of-employer rule: a nonresident performing all work physically outside Colorado for a Colorado-based employer is not Colorado-taxed on those wages solely because the employer is headquartered here. Colorado has been a significant landing spot for remote workers relocating from California, Texas, and the coasts since 2020, and the state has no reciprocal withholding agreements with any other state, so a genuine mid-year move still requires the DR 0104PN part-year split rather than a simple withholding switch.
In Guam
Guam has no convenience-of-the-employer rule of its own, but a mainland employer's own state convenience rule can still reach a Guam-based remote worker's wages if the employer continues to treat them as mainland-sourced. Guam's IRC section 931 exclusion for bona fide residents' Guam-source income is valuable, but only applies cleanly once the employer correctly treats the work as Guam-sourced and DRT-withheld rather than leaving it entangled with a mainland payroll system.
Military
In Colorado
Colorado follows the federal Servicemembers Civil Relief Act and Military Spouses Residency Relief Act. A service member stationed in Colorado on orders does not become a Colorado domiciliary from the posting alone, and neither does an accompanying spouse who elects to keep the service member's home-state domicile under MSRRA. Colorado also offers a military retirement subtraction that interacts with, but does not simply duplicate, the general pension and annuity subtraction.
In Guam
Guam hosts significant U.S. military presence (Andersen Air Force Base and Naval Base Guam) and follows the federal Servicemembers Civil Relief Act (SCRA) and Military Spouses Residency Relief Act (MSRRA): a servicemember's home-of-record does not change solely due to Guam orders, and a civilian spouse can elect to keep the servicemember's tax residence. A servicemember who qualified as a bona fide Guam resident before deployment elsewhere does not lose that status due to absence under military orders, but being stationed on Guam under orders alone does not create bona fide residency.
Airline Crew
In Colorado
Denver International Airport (DEN) is a major hub for United Airlines and a large Southwest Airlines operation, giving Colorado a meaningful resident and crew-base airline population. Federal law (49 U.S.C. §40116) limits state taxation of air carrier employees to their state of residence and any state where they earn more than 50% of their pay, which matters directly for DEN-based crew who fly national routes.
In Guam
Guam's A.B. Won Pat International Airport is a hub connection point for trans-Pacific carriers, and the federal carve-out at 49 U.S.C. section 40116, limiting taxation of air carrier employees to their state or territory of residence and, in limited cases, a jurisdiction where they earn more than half their pay, applies to Guam the same way it applies to the 50 states. Crew who are bona fide Guam residents owe Guam tax on their wages under the mirrored federal framework rather than IRS tax on Guam-source pay.
Tools for This Move
Colorado to Guam FAQ
Does Colorado use the 183-day rule?+
Not exactly as codified. Colorado's six-month rule under Department Rule 39-22-103(8)(a) makes you a statutory resident if you keep a permanent place of abode in Colorado and spend more than six months (commonly treated as 183-plus days) here in the aggregate during the year, separate from and in addition to the ordinary domicile test.
Does Guam have its own separate income tax system like Puerto Rico?+
No. Guam uses a mirror code under 48 U.S.C. section 1421i, meaning it applies the U.S. Internal Revenue Code word for word with 'Guam' substituted for 'United States.' You pay the same 10% to 37% federal brackets, just to Guam's Department of Revenue and Taxation instead of the IRS, which is a fundamentally different structure from Puerto Rico's or American Samoa's independently legislated tax codes.
How does Colorado decide if I'm still domiciled here after I move?+
Colorado weighs 18 non-exclusive factors, including where your driver's license, vehicle registration, and voter registration are, where your spouse and dependents live, your employment location, your mailing address for financial documents, and even public statements of residency. No single factor controls, and once Colorado domicile is established it's presumed to continue until you affirmatively establish a new one elsewhere.
If I get a GEDA Qualifying Certificate, do I automatically qualify as a Guam resident for tax purposes?+
No. A Qualifying Certificate sets up eligibility for a tax reduction, generally up to a 75% income tax reduction for up to 20 years in the standard category, but you must still independently satisfy the federal presence, tax home, and closer connection tests every year, and GEDA and DRT can review whether the underlying business and residency are genuine throughout the certificate term.
I bought a place in Aspen but I'm domiciled in Texas. Do I owe Colorado tax?+
Not from domicile alone, since a person who owns a home in another state but visits Colorado seasonally isn't treated as a Colorado domiciliary absent other factors. But the ski home is a permanent place of abode, so if your aggregate Colorado days exceed six months in a year, the separate statutory six-month rule makes you a Colorado resident regardless of your Texas domicile.
How many days do I need to spend in Guam to be a bona fide resident?+
183 days in the tax year is the cleanest path, but there are four alternatives: 549 days across the current and two prior years with at least 60 days each year, 90 days or fewer in the U.S., $3,000 or less in U.S.-source earned income with more Guam days than U.S. days, or no significant U.S. connection at all. Meeting a presence prong alone is not enough; the tax home and closer connection tests must also be satisfied.
What form do I file if I only lived in Colorado part of the year?+
Form DR 0104 along with the DR 0104PN, the Part-Year Resident/Nonresident Tax Calculation Schedule, which prorates your Colorado tax to income earned while you were a Colorado resident plus any Colorado-source income earned before you arrived or after you left.
I split time between Guam and the CNMI. Which one is my tax home?+
Your tax home is your regular or main place of business or employment, regardless of where you also own property or spend leisure time. The IRS's own Publication 570 example addresses this exact situation: a hotel worker employed seasonally in Guam but living the rest of the year in the CNMI was found to have a Guam tax home because that's where the regular place of business was, even though the CNMI held stronger personal and social ties.
Does Colorado tax Social Security and retirement income?+
Yes, but with a growing subtraction. Through 2025 the pension and annuity subtraction (which covers qualifying Social Security, pensions, and certain IRA income) is capped at $20,000 for filers 55 to 64 and $24,000 for filers 65 and older. Starting with tax year 2026, Colorado removes that cap entirely, letting any individual subtract their full qualifying pension and annuity income.
What tax return do I file if I'm a bona fide Guam resident?+
You generally file Form 1040GU with Guam's Department of Revenue and Taxation reporting your worldwide income, and you're not separately liable to file with or pay the IRS for that year as long as the Guam return is properly filed and the tax fully paid. If you're not a full-year bona fide resident but have Guam-source income, you file with the IRS and may need to attach Form 5074 to allocate tax between the jurisdictions.
Does Colorado have a capital gains tax?+
Capital gains are taxed as ordinary income at the flat 4.40% rate. Colorado used to allow a broad $100,000 subtraction for long-held qualifying property, but since tax year 2022 that subtraction only applies to farmers who file federal Schedule F on the sale of agricultural real property, so most taxpayers get no special break on gains.
Can I keep my mainland home after moving to Guam?+
You can own it, but keeping it available as a livable home for your own use works against you on the closer connection test, which compares your Guam ties to the total of your U.S. and foreign ties. Renting it out at fair market value with limited personal-use days is a safer pattern than leaving it available for regular stays.
Considering the reverse move?
Guam to Colorado
Moving the other direction is a different fact pattern, not a mirror image: exit risk and establishment mechanics both flip.
View the Guam to Colorado guideAlso Consider, Leaving Colorado
Colorado to Guam Reading
Reviewed Against 20 Primary Sources
ResidencyIQ organizes public residency research into a reviewable reference. It does not provide legal or tax advice. Consult a qualified professional before making a residency decision.
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