An employee secondment is a temporary arrangement in which one employer loans a worker to another organization while keeping the original employment contract in place. Three parties are involved: the home employer, which remains the employer of record; the host, which directs the worker’s day-to-day tasks; and the worker, who sits in a legal middle ground between them. Handled well, the arrangement is straightforward. Handled poorly, it exposes both organizations to joint employer liability, unexpected tax bills, and benefit plan problems neither side saw coming.
Internal Versus External Secondments
Secondments come in two forms. An internal secondment moves a worker between divisions, branches, or subsidiaries inside the same corporate group. An external secondment sends the worker to a legally separate organization, typically a client, joint-venture partner, or industry body.
The legal stakes are higher when the two employers share no corporate structure, because questions about control, liability, and taxes cannot be resolved by pointing to a common parent. In both cases the original employment contract stays active, and a separate secondment agreement layers on top of it: what the worker will do, where, for how long, and under whose supervision. The home employer keeps the fundamental power to hire and fire; the host directs the work. That split sounds clean on paper and gets messy in practice, which is why the joint employment question sits at the center of every secondment.
The Joint Employment Risk
The biggest legal exposure in any secondment is that the host ends up classified as a joint employer. Once that happens, both organizations share liability for wage-and-hour violations, discrimination claims, and other employment obligations. The Fair Labor Standards Act defines “employ” broadly as “to suffer or permit to work,” so the host does not need a formal employment contract with the worker to become an employer in the eyes of the law.1Office of the Law Revision Counsel. 29 U.S.C. 203 – Definitions
Federal regulations look at four factors to determine whether the host has crossed into joint employer territory: whether it hires or fires the worker, whether it substantially controls the work schedule or conditions, whether it sets the rate and method of pay, and whether it maintains employment records for the worker.2eCFR. 29 CFR 791.2 The more of those boxes the host checks, the stronger the case for joint employment. A secondment where the host merely provides workspace and project direction looks very different from one where the host sets hours, evaluates performance, and decides whether to extend the assignment.
Courts and enforcement agencies look at what actually happens on the ground, not what the paperwork says. If the host functionally acts as the employer, it becomes one, regardless of the contract’s language.
Discrimination and Safety Liability
Both employers carry anti-discrimination duties toward a seconded worker. The EEOC has stated that when a staffing arrangement gives both organizations the right to control the worker, and each meets the fifteen-employee threshold, they qualify as joint employers under Title VII and the ADA.3U.S. Equal Employment Opportunity Commission. Enforcement Guidance on Application of EEO Laws to Contingent Workers Placed by Temporary Employment Agencies and Other Staffing Firms The ADA defines an employer as a person in an industry affecting commerce with fifteen or more employees.4Office of the Law Revision Counsel. 42 U.S.C. 12111 – Definitions
If a seconded worker is harassed at the host site, both employers can face liability. The home employer is on the hook if it knew or should have known about the discrimination and failed to take corrective action within its control. The host is liable for discriminatory conduct occurring under its supervision. Where both employers’ actions contribute to the harm, they face joint and several liability for back pay, front pay, and compensatory damages, meaning the worker can recover the full amount from either one.3U.S. Equal Employment Opportunity Commission. Enforcement Guidance on Application of EEO Laws to Contingent Workers Placed by Temporary Employment Agencies and Other Staffing Firms
Workplace safety runs in parallel. OSHA’s multi-employer worksite policy allows citations against any employer that creates, exposes workers to, controls, or has the ability to correct a hazardous condition. In a secondment, the host typically functions as both the exposing and controlling employer, while the home employer can still be cited if it knew about hazards and failed to act.5Occupational Safety and Health Administration. CPL 02-00.124 – Multi-Employer Citation Policy The agreement should say which employer handles safety training, provides protective equipment, and reports incidents.
Injuries, Indemnification, and Workers’ Compensation
When a seconded worker injures a third party or damages property during the assignment, financial responsibility depends on who controlled the work that led to the harm. Courts apply the borrowed servant doctrine to decide whether the host has assumed enough control to bear vicarious liability. The factors are whether an implied employment relationship exists between host and worker, whether the worker is primarily engaged in the host’s business, and whether the host directs the details of the work. Both employers can be held liable when both exercised control.
Because of that shared exposure, secondment agreements between unrelated companies almost always include cross-indemnification clauses. Each party typically covers losses arising from its own negligence or breach, and where both share fault, liability is allocated proportionally. Well-drafted agreements also address insurance offsets, reducing any indemnification payment by insurance proceeds the indemnified party receives under its own policies.
Workers’ compensation is a separate puzzle. The home employer’s policy generally covers the worker because the employment relationship stays with the home employer. But if the host exercises enough control to qualify as a “special employer” under the borrowed servant doctrine, the host’s workers’ compensation carrier may also be on the line. The safest approach is to address this explicitly in the agreement rather than fight about it later. Some home employers add the host as an additional insured on their workers’ compensation policy; others require the host to maintain its own coverage for seconded workers.
What the Secondment Agreement Should Cover
The secondment agreement supplements the worker’s existing employment contract and binds all three parties. Vague terms invite the disputes secondments are supposed to prevent.
Duration, Duties, and Termination
The agreement needs a clear start date and either a fixed end date or a defined trigger for conclusion. Open-ended secondments are riskier because they blur the line between temporary assignment and permanent transfer, which affects joint employment analysis and benefit plan obligations. Duties at the host site should be specific enough to prevent scope creep but flexible enough to accommodate reasonable project evolution. Notice periods for early termination commonly run thirty to ninety days, and the agreement should identify what counts as cause for immediate termination by any party, such as material breach, misconduct, or loss of a required license.
Reporting Structure
Name who manages the worker’s daily output at the host site and who handles career development, performance reviews, and discipline at the home employer. Keeping those roles distinct helps support the position that the home employer retains ultimate employment authority. When the host starts running formal performance evaluations or making disciplinary calls, it strengthens the case for joint employment.
Intellectual Property
Federal copyright law treats a “work made for hire” created by an employee within the scope of employment as belonging to the employer by default.6Office of the Law Revision Counsel. 17 U.S.C. 101 – Definitions In a secondment, the question becomes which employer. If the worker creates deliverables for the host’s projects using the host’s resources, a court could find that the host is the employer for work-for-hire purposes. Common approaches are assigning all IP to the host, retaining it with the home employer and licensing it to the host, or splitting ownership by the nature of the work. Patentable inventions need their own provisions, especially if the worker signed a pre-existing invention assignment with the home employer.
Confidentiality and Non-Solicitation
The seconded worker will encounter trade secrets, client lists, and proprietary processes at the host site. Confidentiality provisions should bind the worker and the home employer to protect that information during and after the assignment, and the host should agree to protect the home employer’s confidential information that the worker brings in.
Non-solicitation clauses stop the host from poaching the seconded worker, either through direct offers during the assignment or for a restricted period afterward. These restrictions commonly run one to two years after the secondment ends. Define what counts as solicitation and carve out exceptions for responses to general job postings. In states that limit or ban non-compete agreements, enforceability varies, so the clause should be tailored to the governing jurisdiction.
Payroll and Tax Administration
The home employer usually stays responsible for payroll: issuing paychecks, withholding federal income tax, collecting FICA contributions, and paying the employer share of Social Security and Medicare. FICA defines wages as all remuneration for employment, and the common paymaster rules let related corporations that concurrently employ the same worker designate one entity to handle payments and avoid double taxation.7Office of the Law Revision Counsel. 26 U.S.C. 3121 – Definitions FUTA obligations similarly remain with the entity that meets the statutory definition of employer.8Office of the Law Revision Counsel. 26 U.S.C. 3306 – Definitions
The host reimburses the home employer through periodic invoices covering salary plus a markup for administrative overhead, benefits costs, and employer tax contributions. Both sides need clean records showing the flow of funds, what each payment covers, and how employment taxes were allocated.
Multi-State Withholding and Nexus
Cross-state secondments create withholding headaches. States generally require income tax withholding based on where the work is physically performed, not where the employer is headquartered. If a worker is seconded from a Texas office to a New York project site, the home employer may need to register for withholding in New York after a threshold number of working days. Thresholds vary: some states trigger withholding after as few as fourteen days, others at thirty days, and some use an income-based test. Reciprocity agreements between certain neighboring states simplify the picture by allowing withholding only in the worker’s state of residence.
Corporate tax exposure is a related concern. Having an employee working in a state can establish enough physical presence to create nexus, potentially requiring the home employer to file a corporate income tax return there. Federal law offers some protection: P.L. 86-272 bars states from imposing net income tax when the in-state business activity is limited to soliciting orders for tangible personal property, with orders approved and shipped from outside the state.9Office of the Law Revision Counsel. 15 U.S.C. 381 – Imposition of Net Income Tax If the worker’s activities go beyond solicitation, that protection disappears, and service businesses get no P.L. 86-272 protection at all, since the statute only covers tangible personal property.
Benefits and the Leased Employee Rules
The seconded worker generally stays enrolled in the home employer’s benefit plans throughout the assignment. Health insurance, retirement plan participation, and paid time off continue under the original employment terms, and continuity of service is preserved so the worker does not lose vesting progress or tenure-based benefits.
The tax code adds a wrinkle for longer assignments. Under IRC Section 414(n), a “leased employee” who works for a recipient organization under its primary direction or control, on a substantially full-time basis for at least one year, must be treated as an employee of the recipient for purposes of retirement plan nondiscrimination testing.10Office of the Law Revision Counsel. 26 U.S.C. 414 – Definitions and Special Rules The host’s qualified retirement plan may need to count seconded workers when running coverage and participation tests. The leasing organization can avoid this by maintaining its own qualifying plan for the worker, but only if leased employees make up no more than twenty percent of the recipient’s non-highly-compensated workforce.11Office of the Law Revision Counsel. 26 U.S. Code 414 – Definitions and Special Rules
Companies inside the same controlled group face a related issue. Section 414(b) treats all employees of all corporations in a controlled group as employed by a single employer for retirement plan purposes.10Office of the Law Revision Counsel. 26 U.S.C. 414 – Definitions and Special Rules Internal secondments between subsidiaries do not change that analysis, but external secondments to unrelated companies can inadvertently trigger the leased employee rules if the assignment runs long enough.
Immigration and Work Authorization
Secondments involving workers on employment-based visas need extra planning. An H-1B worker’s visa is tied to a specific employer and work location. When the worker is seconded to a site outside the metropolitan statistical area covered by the existing petition, the sponsoring employer must file an amended H-1B petition with USCIS along with a new or amended Labor Condition Application. The worker can start at the new location as soon as the amended petition is filed, without waiting for approval.12U.S. Citizenship and Immigration Services. USCIS Draft Guidance on When to File an Amended H-1B Petition After the Simeio Solutions Decision
Short-term placements get some relief. No amended petition is needed for assignments of up to thirty days at a new location, or up to sixty days if the worker remains based at the original site. Moves within the same metropolitan statistical area also do not require an amended petition, though the employer must post the original LCA at the new location.12U.S. Citizenship and Immigration Services. USCIS Draft Guidance on When to File an Amended H-1B Petition After the Simeio Solutions Decision Failing to file when required can jeopardize the worker’s status and expose the employer to penalties, so immigration compliance belongs on the checklist before any secondment starts.
Executing and Ending the Arrangement
Once the agreement is signed by all three parties, the home employer’s HR and payroll functions update internal records, adjust billing codes, and set up the reimbursement invoicing schedule with the host. The host handles onboarding: IT access, security credentials, workspace, and any site-specific safety training required under OSHA standards.
At the end of the term, the worker returns to the home employer, where the original position or a comparable role should be available. Off-boarding at the host site includes revoking system access and closing out the reimbursement ledger. The reintegration plan should be outlined in the original agreement so the worker knows from day one that a path back exists.