What is Co-Employment?

If you work in HR and your organization uses staffing agencies, independent contractors, or a professional employer organization, you are almost certainly operating within a co-employment arrangement. That term appears constantly in contracts, compliance discussions, and vendor agreements. For many HR professionals, especially those newer to contingent workforce management, co-employment is not clearly understood. What it means in practice and why it matters are often unclear.

This article covers the fundamentals: what is co-employment, how it works, what it is not, and what a well-structured co-employment relationship looks like for both the organization and the workers it engages. For HR teams navigating the legal dimensions, including current case law, state-specific liability rules, and risk management frameworks for EOR and MSP programs, we’ve published a deeper technical resource: Co-Employment & Joint Employer Law Technical Whitepaper.

What Is Co-Employment?

How Does Co-Employment Work?

The division of responsibilities in a co-employment arrangement follows a fairly consistent pattern, regardless of whether the structure involves a PEO, a staffing agency, or an EOR.

What the Client Company Typically Handles:

• Directing the day-to-day work of the employee, including task assignments and project oversight
• Making decisions about hiring, performance expectations, and whether a placement continues
• Managing the physical or virtual work environment and any tools or equipment the worker uses
• Setting operational standards and workplace policies that govern conduct on-site or in the project

What the Workforce Partner Typically Handles:

• Processing payroll and managing wage payments to the employee
• Withholding and remitting payroll taxes to federal, state, and local authorities
• Administering employee benefits, including health insurance, retirement plans, and leave
• Providing workers’ compensation coverage and managing claims
• Maintaining HR compliance with applicable labor laws and regulatory requirements
• Managing onboarding documentation, employment records, and separation processes

The co-employment agreement formalizes this division. The contract defines authority, liability, and responsibility when/ if issues arise.

Why Co-Employment Exists: The Business Context

Co-employment has scaled in parallel with the contingent workforce. According to the U.S. Bureau of Labor Statistics, 6.9 million American workers, representing 4.3%of the total employed population, held contingent jobs as their main role as of July 2023, up from 3.8% in 2017. The U.S. Government Accountability Office estimates that contingent workers already represent 30% to 40% of the broader U.S. labor market when all flexible work arrangements are counted.

Why Contingent Work is Driving Co-Employment

Organizations use contingent workers for legitimate operational reasons: filling specialized skill gaps, managing project-based work, maintaining flexibility during periods of growth or change, and controlling labor costs. But employing workers, even on a temporary basis, comes with legal and administrative obligations. At its core, co-employment solves an infrastructure problem. Organizations gain access to flexible talent without building the full employment administration layer internally.

Co-Employment vs. Related Terms: What It Is Not

HR teams often confuse co-employment with other workforce and legal concepts. These distinctions matter because they determine compliance obligations and risk exposure.

Co-Employment vs. Joint Employment

Co-employment is a structured, intentional arrangement with clearly defined roles. Joint employment refers to a legal finding that two entities both exercise meaningful control over the same workers, often without either party planning for or formalizing that shared authority. Joint employment tends to arise when the lines of operational control become blurred, such as when a client company begins managing a staffing agency’s workers as if they were its own employees. Co-employment describes the structure; joint employment describes what happens when that structure breaks down or was never properly established.

Co-Employment vs. Worker Misclassification

Worker misclassification occurs when a single employer incorrectly labels an employee as an independent contractor to avoid tax obligations, benefit costs, or labor protections. Co-employment involves two employers with a legitimate shared arrangement. These two issues can intersect because a staffing arrangement that drifts toward co-employment without proper structure can also surface misclassification risk, but they are governed by different legal theories and carry different consequences.

Co-Employment vs. Employee Leasing

Employee leasing involves a staffing agency or leasing company providing workers to a client for temporary assignments. The workers belong to the leasing agency’s pool and return to it when the assignment ends. In a true co-employment relationship, the active workforce is not supplemented by an outside labor pool. The workers are already employed in a structured shared arrangement, not on loan from a third party’s roster.

Co-Employment vs. Employer of Record (EOR)

An employer of record arrangement is a form of co-employment, but with the EOR assuming full legal employer status. In a standard co-employment arrangement, both parties share employer responsibilities. In an EOR model, the EOR becomes the legally recognized employer of record for tax, compliance, and benefits purposes, while the client directs the work. EOR structures are commonly used by organizations hiring internationally, where the EOR provides a legal entity in the worker’s country without requiring the client to establish one. The client directs the work; the EOR holds the employment relationship.

Where a Managed Service Provider (MSP) Fits In

A managed service provider, or MSP, is a different kind of workforce partner, and one that HR professionals at mid-to-large organizations will encounter frequently. Where a PEO or EOR is the employer of the workers in the arrangement, an MSP is not. Its role is program management. It oversees suppliers, staffing agencies, and contractor channels, typically through a vendor management system (VMS). In practice, the MSP consolidates intake, manages agency relationships, tracks compliance, handles invoicing, and provides reporting across the whole program. Importantly, the employment relationship still runs between each supplier and its workers.

How MSPs Differ From PEOs and EORs

That distinction matters for co-employment because the MSP’s structure is designed to keep the client at arm’s length from the direct employment relationship. The agencies in the program are the employers; the MSP governs how those agencies operate; and the client directs the outcomes of the work. When that structure is maintained cleanly, it supports a defensible co-employment posture across a large, complex contingent program. Risk increases only when governance boundaries are not followed, such as when client managers bypass suppliers or directly supervise contingent workers.

How MSPs Protect Against Co-Employment Risk

For HR professionals managing smaller contingent programs, a PEO or EOR may be the more relevant model. For enterprise-scale programs, an MSP adds governance and oversight that a PEO or EOR does not provide. The three models serve different workforce needs, and some organizations use a combination: an MSP to manage the overall program, with EOR arrangements for specific worker categories, particularly international hires or specialized independent contractors.

When an MSP Makes Sense

Understanding where each model sits in the co-employment spectrum and which one applies to your workforce is foundational to managing the arrangement well. The legal implications of each, including how courts have evaluated MSP and EOR structures when co-employment claims arise, are covered in detail in our white paper.

What a Well-Structured Co-Employment Agreement Looks Like

The co-employment agreement, often called a client service agreement (CSA), is where the arrangement is formalized. A well-written CSA does not just outline services; it clearly allocates authority and liability between the parties.

Key Elements of a Strong Co-Employment Agreement Include:

Clear Definition of Employer Responsibilities:

The CSA should specify, in explicit terms, which party handles payroll, which holds hiring authority, which manages performance, and which is responsible for compliance under each applicable law.

Liability Allocation:

Both parties should understand their exposure. A well-drafted agreement distributes risk to the party best positioned to manage it and, where permitted by applicable law, includes indemnification provisions for specific compliance failures.

Worker Classification Terms:

The agreement should define how workers engaged under the arrangement are classified, what that classification is based on, and the process for reviewing classifications over time.

Benefit Plan Definitions:

Benefit plans administered by the co-employer should clearly define which workers are covered, and any plans maintained by the client company should explicitly define whether and how contingent workers are included or excluded.

Termination and Transition Provisions:

The agreement should address what happens to active workers if the co-employment arrangement ends, including which party retains the employment relationship and how that transition is managed.

It is worth noting that a well-written contract is necessary but not sufficient. Courts prioritize how the relationship operates in practice over what the contract says. In short, the agreement sets the structure; operational discipline sustains it.

Why a Workforce Partner Matters in a Co-Employment Model

For HR professionals who are not HR departments of one, and who may be managing a contingent program in addition to a full slate of other responsibilities, the value of a capable workforce partner in a co-employment arrangement goes beyond administrative convenience.

Administrative Burden vs. Strategic Focus

A workforce partner absorbs employment administration at scale. This covers payroll taxes, workers’ compensation, benefits, and compliance. It also requires staying current with tax rules across jurisdictions, managing claims, and maintaining compliant onboarding and offboarding processes. For multi-state organizations, the compliance landscape is substantial and constantly changing.

Managing Administrative Complexity at Scale

HR teams that might otherwise spend significant time on payroll processing, benefits administration, and compliance tracking can redirect those hours toward workforce planning, talent strategy, and work that requires human judgment.

What to Look For in a Workforce Partner:

Compliance Infrastructure:

The partner should have demonstrated the capability to manage employment obligations across the states and countries where your workforce operates, with processes for tracking regulatory changes and updating practices accordingly.

Transparent Role Delineation:

The partner should be able to articulate clearly, in writing and in practice, which responsibilities belong to them, and which remain with your organization. Ambiguity in this area is a risk factor, not a minor administrative detail.

Benefits Access:

One of the primary reasons organizations enter co-employment arrangements is access to competitive benefits that would otherwise be unavailable or cost-prohibitive at their scale. A strong partner offers a substantive benefits package, not just a bare minimum.

Program Governance Support:

For organizations managing a larger contingent workforce, the partner should bring more than operational processing. Proactive compliance guidance, manager training resources, and regular program reviews are hallmarks of a partner invested in the arrangement’s health over time.

Co-Employment and Legal Risk: What HR Teams Should Know

Co-employment is a legally recognized arrangement, and when structured properly, it works. It operates in a fragmented and frequently changing regulatory environment. Federal laws like the FLSA, Title VII, ADA, and NLRA apply alongside stricter state frameworks.

Where Co-Employment Risk Comes From

HR professionals should focus less on case law and more on the behaviors that create compliance exposure. Most risks do not come from misconduct. They come from operational drift: client managers supervising contingent workers like employees, assignments extending too long, and systems blurring worker status.

Worker location matters. States like California, New Jersey, Illinois, Massachusetts, and New York impose stricter co-employer liability standards than federal law. For multi-state programs, those state standards are the effective compliance floor.

State Law Sets the Compliance Floor

Going deeper: If your organization is managing EOR or MSP arrangements, or if you are navigating the current regulatory environment around joint employer standards at the federal and state levels, our whitepaper covers the active legal landscape in detail, including current NLRA and FLSA standards, relevant case law, and what compliant program structures look like in practice.

The Takeaway for HR Professionals

Co-employment, at its core, is a practical framework: two organizations sharing employer responsibilities for the same worker, with each party accountable for the functions it is best positioned to manage. When that framework is clearly defined, properly documented, and consistently followed in practice, co-employment works well for all parties involved, including the workers themselves.

Many HR professionals are already operating within a co-employment arrangement, and this guide explains what that means and how to handle it. Organizations run into trouble when they treat co-employment as stock language in a vendor contract and never build the operational discipline to match.

A qualified workforce partner should make that discipline easier, not harder, by bringing the infrastructure, compliance expertise, and program governance support that allows your HR team to focus on the workforce strategy that drives your organization forward.

What A Strong Workforce Partner Delivers

A qualified workforce partner brings three capabilities that are difficult to build internally, especially without dedicated compliance resources:

• Regulatory intelligence that tracks legislative changes across jurisdictions and translates them into program adjustments before they become enforcement risks.
• Program governance frameworks that define role boundaries, escalation protocols, and compliance checkpoints as standard operating procedure rather than reactive measures.
• Risk allocation infrastructure, including clear contract language, indemnification provisions, and benefit plan exclusions that distribute liability to the party responsible for the relevant compliance obligation.

Market Growth and Increasing Enforcement

Allied Market Research projects the global contingent workforce management market will grow at a 10.5% CAGR from 2021 to 2031, reaching $465.2 billion. As the contingent workforce continues to grow, governments worldwide are increasing enforcement activity proportionately.

For HR teams managing flexible workforce programs, co-employment is not a legal technicality. It is a core workforce management discipline. It is a workforce management discipline that belongs at the center of how contingent talent programs are designed and operated from day one.

Understanding co-employment, its structure, and its risks is foundational. So are the operational practices that keep arrangements compliant. Those that get this right are the organizations treating co-employment as a management priority, not a contract clause.

Q&A

What is co-employment, and why do organizations use it?

Co-employment is defined as a structured arrangement where two separate organizations share employer responsibilities for the same worker. The client company directs day-to-day operations, while a workforce partner (such as a staffing agency, PEO, EOR, or MSP) handles employment infrastructure, including payroll, taxes, benefits, compliance, and workers’ compensation. 

In a co-employment model, who is responsible for what?

Client company typically directs daily work and project oversight; sets performance expectations; makes continuation decisions; manages the work environment and tools; and sets on-site or project policies. Workforce partner typically runs payroll and wage payments; withholds and remits payroll taxes; administers benefits; provides workers’ compensation coverage; ensures HR compliance; and manages onboarding records and separations. These allocations are formalized in a co-employment or client service agreement that clarifies authorities, responsibilities, and liability.

What should a strong co-employment agreement (CSA) include?

A robust CSA clearly delineates employer responsibilities (hiring, performance, payroll, compliance), allocates liability to the party best positioned to manage it (often with targeted indemnification), defines worker classifications and periodic review processes, specifies benefit eligibility and any client plan exclusions, and lays out termination/transition steps for active workers if the relationship ends. Crucially, courts weigh actual conduct more than contract language — operational discipline must match what the CSA says.

What are the biggest co-employment risk triggers, and how can HR mitigate them (especially across states)?

Common risk triggers include operational “drift” (client managers supervising contingents like employees), overlong assignments, and systems integrations that blur worker status. State laws (notably CA, NJ, IL, MA, NY) often set stricter co-employer liability standards than federal rules, creating a higher compliance floor for multi-state programs. Mitigation includes: clear role boundaries and routing decisions through suppliers/MSPs; manager training; periodic program reviews; and partnering with providers that offer strong compliance infrastructure, regulatory tracking, program governance, and well-crafted contracts (including indemnities and plan definitions). Consistent practice is what keeps co-employment defensible.

Does using an MSP reduce or increase co-employment exposure? 

Structured correctly, an MSP reduces exposure by keeping the client at arm’s length from direct employment. In an MSP model, suppliers are the employers; the MSP governs supplier performance via the VMS, consolidates intake, tracks compliance, handles invoicing, and reports on the program. Risk rises when client managers bypass suppliers—directly supervising workers or deciding whether engagements continue—eroding the intended separation. Maintaining clean governance lines supports a defensible co-employment posture at scale.

How do stricter state standards affect multi-state co-employment programs?

States like California, New Jersey, Illinois, Massachusetts, and New York often set stricter co-employer liability standards than federal rules. For multi-state programs, those states effectively set your compliance floor. Align policies and operational practices to the strictest applicable standard, and partner with providers that bring strong multi-jurisdiction compliance infrastructure and regulatory tracking. For deeper legal detail (e.g., NLRA/FLSA standards and case law), see: Co-Employment & Joint Employer Law Technical Whitepaper