Moving from Missouri to California: Residency, Taxes, and What to Prove

In Missouri

Missouri has no statutory carve-out for travel nurses distinct from its general residency test; the federal tax-home question under IRS Publication 463 governs stipend treatment, and Missouri residency then follows the statutory domicile/183-day framework like any other taxpayer. Missouri's major hospital systems in St. Louis, Kansas City, and Springfield draw a steady stream of travel nursing assignments, and a nurse who claims an out-of-state tax home while actually renting and living in Missouri most of the year risks the same tax-home disallowance pattern documented nationally on travel-nurse forums, which would also expose them to Missouri's statutory 183-day resident test if they maintain a Missouri residence.

In California

California is both a major origin state, since many nurses domiciled here take travel contracts elsewhere, and the single highest-paying destination state for travel assignments. A nurse's tax home must be a genuine, regularly-returned-to residence with duplicated living expenses; nurses who claim a tax home in Texas or Florida but never actually go back risk having the FTB or IRS reclassify housing stipends as taxable wages if the facts show California, not the claimed state, is really home. A nurse domiciled outside California who works a temporary California assignment as a W-2 traveler does not become a California resident from that assignment alone, but the wages earned during the California contract are still California-source and must be reported on a nonresident Form 540NR.

In Missouri

Missouri is home to the Chiefs (whose stadium sits in Missouri just across the state line from Kansas), Royals, Cardinals, and Blues. Missouri applies duty-day apportionment to nonresident professional athletes' income earned from games and team activities in Missouri, consistent with how most income-tax states administer the jock tax, and Missouri-domiciled players on these teams owe Missouri tax on their full income before credits for tax paid to other states where they play road games.

In California

California is the most aggressive jock-tax state. FTB counts not just game days but practices, walkthroughs, and even voluntary workouts held at a California team facility during game week, which can turn one road game into three or four California duty days. With the Lakers, Clippers, Warriors, Kings, 49ers, Rams, Chargers, Dodgers, Giants, Padres, and Athletics all based here, nonresident athletes playing any California team face California nonresident tax on their duty-day-apportioned income, while California-domiciled athletes owe California tax on their full worldwide income.

In Missouri

A Missouri snowbird who is Missouri-domiciled and winters in Florida or Arizona only escapes Missouri tax as a nonresident if they maintain no permanent Missouri residence, keep a permanent residence in the destination state, and spend 30 days or fewer in Missouri for the entire year, which is a much tighter safe harbor than most states offer. A non-domiciled owner of a Missouri vacation or second home faces the opposite risk: maintaining a permanent Missouri residence and crossing 183 days in the state during the year makes them a Missouri statutory resident regardless of where they consider their true domicile.

In California

The nine-month presumption under §17016 only creates a rebuttable presumption of residency past that point; it does not create a safe harbor below it. Spending fewer than nine months in California does not guarantee nonresidency; FTB still applies the closest-connections test. This is the classic dual-home audit target described across Bogleheads and r/tax threads: a retiree who keeps the California house, splits time with a Nevada or Arizona property, but leaves a spouse, kids, doctors, or the majority of actual annual days in California.

In Missouri

Missouri has no convenience-of-the-employer rule, so a genuine Missouri resident working remotely for an out-of-state employer is taxed as a Missouri resident regardless of employer location, and a nonresident working remotely for a Missouri employer generally is not pulled into Missouri tax solely because the employer is headquartered there. The recurring Missouri-specific version of this is Kansas City and St. Louis metro commuters whose employer sits on the other side of a state line; because Missouri applies its statutory 183-day and permanent-residence test rather than a convenience rule, actual physical work location and Missouri presence both matter for anyone with ties on both sides.

In California

California has no convenience-of-employer rule like New York's. A nonresident who physically performs all their work outside California for a California-headquartered employer is not California-taxed on those wages solely because the employer is based here. The trigger is the employee's own residency and physical work location, not the employer's address. A California resident, however, owes California tax on remote wages regardless of where the employer sits.

In Missouri

Missouri follows the federal Servicemembers Civil Relief Act and Military Spouses Residency Relief Act. A servicemember whose home of record is Missouri remains a Missouri domiciliary and taxpayer regardless of duty station, and Missouri does not tax a nonresident servicemember's military pay solely because they are stationed in Missouri under orders. Fort Leonard Wood and Whiteman Air Force Base are the state's major installations, and a nonmilitary spouse residing in Missouri solely due to military orders can elect the servicemember's state of legal residence under MSRRA.

In California

California follows the federal Servicemembers Civil Relief Act and the Military Spouses Residency Relief Act. Active-duty military domiciled outside California but stationed here under orders are not California residents and their military pay isn't California-taxed. Under MSRRA and the Veterans Benefits and Transition Act, a nonmilitary spouse can elect the servicemember's domicile for state tax purposes instead of being pulled into California residency by physical presence alone.

In Missouri

Federal law (49 U.S.C. §40116) limits any state's ability to tax an air carrier employee's pay to the employee's state of residence and any state where more than 50% of pay is earned. Kansas City International and St. Louis Lambert are both significant airports, and Southwest and other carriers maintain crew presence in the Kansas City metro; crew based there who are domiciled elsewhere are protected by the federal carve-out from full Missouri taxation solely because Missouri is their duty station.

In California

Federal law (49 U.S.C. §40116) limits taxation of air carrier employees to their state of residence and any state where they earn more than 50% of their pay, overriding ordinary duty-day sourcing. California hosts major crew bases at LAX and SFO, so this carve-out matters heavily for California-based flight crew who fly national or international routes.