Switching travel nursing agencies mid-year does not reset your tax home status or restart the IRS one-year clock on an assignment — both depend on your physical assignment location, not which agency issues your paycheck. What it does reset: your W-4 elections, your 401(k) vesting clock, and — if you already worked for one agency this year — it can leave you with excess Social Security tax withheld that you can claim back on your federal return.
Key takeaways
- Your tax home and the IRS one-year rule track your physical assignment location and duration, not your employer — switching agencies while staying in the same metro area does not restart either clock.
- Two W2 employers in the same year can each withhold Social Security tax up to the annual wage base independently, meaning you can have more withheld combined than the law allows — and it comes back as a credit on your federal return, not automatically.
- Your W-4 elections do not transfer between agencies — a new employer starts you at default withholding unless you resubmit Steps 2 and 4(c).
- 401(k) vesting schedules are employer-specific. Switching agencies before you’re vested can forfeit the employer match you’ve accumulated so far.
What does not reset when you switch agencies
Your tax home is defined by where you maintain a permanent residence, incur duplicated living expenses, and return between assignments — none of which has anything to do with which staffing agency employs you. Switching agencies mid-assignment or between assignments doesn’t touch your tax home status one way or the other.
The IRS one-year rule works the same way. If you stay in the same general work area, the IRS aggregates consecutive and serial contracts toward the 12-month indefinite-assignment threshold under Revenue Ruling 93-86 — regardless of whether you switched staffing agencies partway through. A new agency does not give you a fresh 12-month clock in the same location. See The IRS One-Year Rule for the full aggregation mechanics.
Excess Social Security withholding across two employers
Each employer withholds Social Security tax independently, at 6.2% of wages up to the annual wage base ($184,500 for 2026), with no visibility into what any other employer withheld from you that same year. If you earn above the wage base combined across two or more W2 agencies, each one keeps withholding 6.2% on its own payroll — with no ceiling coordinated between them — so your combined withholding can exceed the legal maximum for the year.
The IRS calls this excess Social Security tax withheld (Topic no. 608), and it’s claimed as a credit on Schedule 3 of Form 1040 — not automatically refunded by either employer. You have to calculate it and claim it yourself when you file. It only applies to Social Security tax (the 6.2% portion); Medicare tax has no wage base and isn’t affected.
This only comes up if your combined W2 wages across agencies actually exceed the annual wage base — most single-agency travel nurses won’t hit it, but nurses who switch employers mid-year while working a lot of overtime, or who work two agencies concurrently, should check their year-end W-2s for this specifically.
Your W-4 starts over at each new agency
A new employer has no record of your prior withholding elections — you’ll fill out a fresh W-4 that defaults to standard withholding unless you actively add Step 2 (multiple jobs) or Step 4(c) (extra withholding). Travel nurse pay structures already tend to under-withhold by default because a large share of the package is tax-free stipends the W-4 doesn’t account for; a new agency compounds that if you don’t redo the adjustment. See Travel Nurse W-4 Withholding for exactly how to set Step 2/4(c) and the safe-harbor threshold to avoid an underpayment penalty.
Retirement account vesting resets too
Agency 401(k) plans have their own vesting schedules for the employer match, separate from your own contributions (which are always fully yours). Leaving before you’re vested forfeits the unvested portion of the match, even if your account balance shows it. If you’re mid-vesting and considering a switch purely for a marginally better rate, weigh the forfeited match against the pay difference. Full comparison of W2 401(k) vesting versus 1099 SEP/Solo 401(k) options is in Retirement Accounts for Travel Nurses.
Switching from W2 to 1099 (or back) mid-year
If the new agency offers the assignment as 1099 instead of W2, you become responsible for both halves of FICA (15.3% self-employment tax) and quarterly estimated payments the moment that contract starts — nothing carries over from the W2 side. Compare the real after-tax difference before accepting a 1099 offer that looks similar on paper; the break-even math is in W2 vs. 1099 Travel Nurse: The Real Tax Math.
FAQ
Does switching agencies affect my tax home?
No. Tax home status depends on maintaining a permanent residence, duplicated living expenses, and returning between assignments — none of that changes because your paycheck comes from a different staffing agency.
Will I automatically get back excess Social Security tax I overpaid?
No — you have to calculate and claim it yourself as a credit on Schedule 3 of Form 1040 when you file. Neither employer will refund it, since each one only sees its own payroll.
Do I need to tell my new agency about my old W-4 elections?
You’ll fill out a brand-new W-4 with the new agency from scratch — there’s no transfer of elections between employers. If you had Step 2 or Step 4(c) adjustments with the old agency to avoid underwithholding, make the same adjustments again with the new one.
Does a gap between contracts hurt my tax home?
A reasonable gap between assignments while you search for the next contract doesn’t by itself disqualify your tax home, as long as you’re still maintaining the residence and haven’t abandoned the area. It’s the same test either way — agency continuity isn’t one of the three IRS factors.
Comparing a new agency’s W2 offer against a 1099 one, or just want to see your real take-home either way? Run the numbers through our W2 vs. 1099 Calculator.