Global mobility compliance is the bundle of immigration, tax, payroll, and labor obligations a company inherits the moment an employee starts working outside their home jurisdiction. One employee crossing a state line or a national border can create new withholding duties, corporate tax filings, work-authorization requirements, and registration obligations that did not exist the day before. Getting any part of it wrong exposes the business to back taxes, penalties, and restrictions on its ability to operate in the new location.
Work Authorization for the Employee
If the person you’re moving is a foreign national coming to work in the United States, the correct visa classification has to be in place before they start. The Immigration and Nationality Act is the governing federal statute.1GovInfo. Immigration and Nationality Act Employers typically file Form I-129, Petition for a Nonimmigrant Worker, with USCIS, either online or by mail.2U.S. Citizenship and Immigration Services. I-129, Petition for a Nonimmigrant Worker Standard processing can take a few weeks to several months depending on the category and USCIS backlog. Premium processing guarantees an initial response within a set number of business days, but that response can be a request for additional evidence rather than an approval. Effective March 1, 2026, premium processing costs $2,965 for most nonimmigrant worker classifications (H-1B, L-1, O-1, TN, and others) and $1,780 for H-2B and R-1 petitions.3U.S. Citizenship and Immigration Services. USCIS to Increase Premium Processing Fees
Every employer, regardless of the employee’s citizenship, must complete and retain Form I-9 to verify identity and work authorization. Those records have to be producible within three business days if federal officers request an inspection.4U.S. Citizenship and Immigration Services. Handbook for Employers M-274 – 10.0 Retaining Form I-9 Employing someone without valid work authorization carries civil penalties that start at $250 to $2,000 per unauthorized worker for a first offense and rise to $3,000 to $10,000 per worker for employers with multiple prior orders.5Office of the Law Revision Counsel. 8 USC 1324a – Unlawful Employment of Aliens Those statutory ranges are adjusted for inflation, so real-world assessments tend to run higher than the base figures suggest.
Where the Employee Owes Income Tax
An employee’s move almost always triggers a new withholding obligation for the employer. At the federal level, the IRS uses the Substantial Presence Test to decide whether a foreign national is a U.S. tax resident, counting days of physical presence over a three-year window.6Internal Revenue Service. Substantial Presence Test Anyone who meets that test or the green card test is treated as a U.S. tax resident.7Internal Revenue Service. Determining an Individual’s Tax Residency Status
State rules are less uniform. Many states use a 183-day threshold as part of their statutory residency tests: an individual with a home available year-round in the state who spends more than 183 days there in the year can be classified as a resident regardless of where they claim their permanent home. Other states trigger withholding for nonresident employees after far fewer days of work, and some do so from the first day. There’s no single national standard, so employers have to track each state’s rules on their own.
Where a tax treaty applies, the employer can reduce or eliminate withholding by having the employee file Form 8233 with the withholding agent. The employee has to be a resident of the treaty country, be the beneficial owner of the income, and identify the specific treaty article. A new Form 8233 is required for each tax year and each withholding agent.8Internal Revenue Service. Instructions for Form 8233
Where the Company Owes Tax: Nexus and Permanent Establishment
This is where mobility programs get blindsided. Placing a single employee in a new state can create corporate income tax nexus, meaning the state now treats the company as doing business there and expects returns and tax on apportioned income. A remote worker answering emails from an apartment can be enough to establish physical presence.
Public Law 86-272 offers a narrow shield: a state cannot impose a net income tax on a company whose only in-state activity is soliciting orders for sales of tangible personal property, provided those orders are approved and fulfilled from outside the state.9Congress.gov. The Evolution of P.L. 86-272’s State Income Tax Immunity The protection does not extend to companies selling services, software, or digital products, and several states have taken the position that remote employees performing activities beyond solicitation, such as customer support or contract fulfillment, fall outside the shield.
Internationally, the risk is creating a permanent establishment. Under most tax treaties following the OECD model, a permanent establishment exists when a company has a fixed place of business in a country, or when a dependent agent habitually concludes contracts on the company’s behalf there. Once that threshold is crossed, the company owes corporate income tax in the foreign jurisdiction on profits attributable to the establishment. A single employee who negotiates and closes deals from a foreign location can trigger it.
Registering the Company in the New State
Corporate income tax nexus is separate from the business registration requirement, and both can be triggered by the same employee. Most states require any corporation, LLC, or limited partnership doing business within their borders to register as a foreign entity with the secretary of state through a process called foreign qualification. Filing fees and annual report requirements vary by state.
The consequences of skipping this step are immediate. An unregistered company generally cannot file or maintain a lawsuit in the state’s courts, which means it cannot enforce contracts or collect debts through litigation there. States can also assess back fees for every year the company should have been registered, and the attorney general may seek to block the company from doing business in the state altogether.
Payroll Taxes When Location Changes
Every paycheck to a mobile employee has to reflect the correct payroll tax withholding for the location where the work is actually performed. Federally, employers pay Social Security tax at 6.2% and Medicare tax at 1.45% on each employee’s wages, for a combined employer share of 7.65%.10Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates The Social Security tax applies only up to the wage base, which is $184,500 for 2026.11Social Security Administration. Contribution and Benefit Base Medicare has no wage cap.
The Federal Unemployment Tax Act imposes a 6.0% tax on the first $7,000 paid to each employee during the year. Employers who pay state unemployment taxes on time receive a credit of up to 5.4%, reducing the effective FUTA rate to 0.6% in most cases.12Internal Revenue Service. Topic No. 759, Form 940 – FUTA Tax Return Filing and Deposit Requirements When an employee moves to a new state, the employer typically has to register with that state’s unemployment insurance program and begin paying state unemployment taxes there. New employer rates vary by state and sometimes by industry.
Federal law also requires employers to report new and rehired employees to the state where those employees work within 20 days of the hire date.13Administration for Children and Families. New Hire Reporting An employee who relocates mid-assignment may need to be reported as a new hire in the destination state, depending on how that state interprets the requirement.
Social Security on International Assignments
When an employee works abroad, both the U.S. and the host country may claim the right to collect social security taxes on the same earnings. The United States has bilateral totalization agreements with 30 countries to prevent this double taxation. Under most of these agreements, an employee sent on a temporary assignment expected to last five years or fewer stays covered exclusively by the home country’s system.14Social Security Administration. U.S. International Social Security Agreements
To claim the exemption, the employer requests a Certificate of Coverage from the Social Security Administration, available online, by mail, or by fax.15Social Security Administration. Certificate of Coverage The certificate is presented to the foreign authorities to avoid double contributions. Without it, both countries may withhold, and the employer pays twice. For assignments to countries with no totalization agreement, there is no automatic exemption, and the employer can owe social security taxes in both jurisdictions at the same time.
Shadow Payroll
When an employee on an international assignment keeps getting paid through their home country’s payroll, the host country still expects local tax and social security to be reported and remitted. A shadow payroll handles this by mirroring the employee’s compensation, calculating what would be owed under the host country’s rules, and generating the filings needed there. No actual wages flow through it; it exists purely for reporting and remittance. Shadow payroll also supports tax equalization policies, where the company ensures the employee does not pay more total tax because of the assignment than they would have paid staying home. Without it, the employee risks double taxation on the same income and the employer risks penalties for failing to withhold in the host country.
Wage Rules, Workers’ Comp, and Benefits
Labor law follows the employee’s physical work location. The Fair Labor Standards Act requires that most nonexempt employees receive overtime pay at one and a half times their regular rate for hours worked beyond 40 in a workweek.16U.S. Department of Labor. Overtime Pay When an employee is working in a state with stricter wage or overtime standards, the employer must follow whichever law is more favorable to the employee.17U.S. Department of Labor. Wages and the Fair Labor Standards Act An employer that violates federal minimum wage or overtime rules is liable for the unpaid wages plus an equal amount in liquidated damages, effectively doubling the bill.18Office of the Law Revision Counsel. 29 USC 216 – Penalties
Workers’ compensation trips up employers with distributed teams. Most states require coverage for employees physically working within the state, even remotely. An employee who moves from one state to another may need to be covered under the new state’s program, and requirements, reporting rules, and approved insurers differ by jurisdiction.
Health benefits add another layer. ERISA, the federal law governing most employer-sponsored health and retirement plans, preempts state insurance regulations for self-funded plans, which gives large multistate employers some uniformity.19U.S. Department of Labor. ERISA Fully insured plans remain subject to the insurance laws of the state where the policy is issued, and a relocated employee may find their plan’s provider network offers poor coverage in the new location. Employers need to confirm that relocated employees have meaningful access to in-network care, which sometimes means offering a different plan option.
The Data You Need Before Any of This Works
None of the obligations above can be met without accurate, centralized data. At a minimum, the company needs each mobile employee’s home jurisdiction, host jurisdiction, exact dates of physical presence in each location, total compensation including bonuses and equity, and current visa or work authorization status. Travel logs and internal relocation requests are the raw material.
Getting the home-versus-host distinction right from the start matters a lot. The home jurisdiction is where the employee normally works; the host is where they are temporarily or permanently going. That distinction drives which tax treaties apply, which payroll withholding rules govern, and whether the company needs to register in a new state. Bad data at this stage cascades into miscalculated withholding, late filings, and failed visa applications downstream.
For employees who may claim tax treaty benefits, the data requirements go further: residency in the treaty country, the specific treaty article that applies, and whether the employee has a fixed base of operations in the U.S. that might disqualify them. Collecting this upfront avoids expensive year-end corrections.
Keeping Compliance Current
The initial filings are the beginning, not the end. Compliance has to be monitored for as long as the employee is in the host jurisdiction, and sometimes longer.
Trailing tax liabilities are among the most commonly missed obligations. When an employee receives a bonus or equity that vests after they have left a jurisdiction, that compensation may still be taxable where the work was originally performed. These liabilities can persist for years after the employee has moved on, requiring coordination between payroll and tax advisors to allocate the income correctly.
Visa expiration dates need their own tracking. Renewals should be initiated months before expiration to absorb processing delays. An employee whose work authorization lapses creates immediate legal exposure for the employer.
Role changes can also trigger new compliance requirements. A promotion, a shift in duties, or a move to a different department may invalidate the original visa classification or alter tax status. A worker originally authorized for a specialized technical role who begins managing a sales team may no longer be covered by the original petition. Periodic reviews catch these before they become violations.
The company’s own footprint needs monitoring too. Corporate registrations, unemployment insurance accounts, and state withholding accounts each carry annual reports, tax rate notices, and renewal deadlines. Missing one can bring penalties or involuntary loss of the company’s authority to do business in that state.