Private Equity Investment in U.S. Law Firms (Part II): Deal Architecture, Regulatory Boundaries, and the Lender Playbook

In our prior Sidley Update, “Private Equity Investment in U.S. Law Firms: Current Models and Recent Developments” (November 25, 2025), we provided a high-level overview of the principal pathways being used to facilitate third-party investment (including private equity investment) in U.S. law firms, including management services organization (MSO)/split-practice structures and, in a handful of jurisdictions, alternative business structure (ABS) regimes or regulatory sandboxes. This article (Part II) builds on that foundation and focuses on execution: how these transactions are architected and documented in practice, where the key ethics and regulatory pressure points typically arise, and what lenders often require to underwrite and collateralize financings in this market.

For decades, Model Rule 5.4-style restrictions on nonlawyer ownership, control, and fee sharing meant that U.S. law firms were largely off-limits to traditional private equity ownership. Today, the landscape is evolving in a handful of jurisdictions, but most transactions still rely on carefully structured MSO arrangements in nonpermissive states. Sidley is active in this market and has experience representing buyers/sponsors, sellers and law firm principals, and lenders in connection with these investments and financings.

I. A Changing Regulatory Landscape

As discussed in our prior Sidley Update, the foundational barrier to traditional private equity investment in U.S. law firms is the principle of lawyer independence, reflected in Model Rule 5.4-style prohibitions on nonlawyer ownership, control, and fee sharing. Even apart from ethics rules, law firms often present structural challenges for leveraged investment, including limits on enforceable noncompetes for lawyers, revenue tied to individual relationships, and practice-area-specific cash flow volatility (particularly in contingency-fee matters). These constraints have historically made conventional buyout structures difficult, and they continue to shape how sponsors and lenders design transactions.

The U.S. independence model remains a patchwork: Most jurisdictions continue to follow some version of Model Rule 5.4, while a limited number have created jurisdiction-specific pathways for nonlawyer economic participation.

Arizona represents the most significant departure, having eliminated its version of Rule 5.4 and implemented an ABS licensing regime. Utah has permitted certain nontraditional ownership and delivery models through its regulatory “sandbox,” and Washington, D.C., has long had a limited exception permitting certain nonlawyer ownership where the nonlawyer assists the firm in providing legal services and agrees to be bound by applicable conduct rules.

Recent developments include Puerto Rico’s adoption of new ethical rules allowing nonlawyers to own up to 49% of a law firm (with a planned reassessment after three years) and California’s October 2025 enactment of legislation restricting fee sharing with out-of-state ABSs while leaving room for properly structured MSO arrangements (e.g., flat-fee MSO compensation that is not tied to recoveries and does not pay for referrals or lead generation).

Several other jurisdictions continue to study potential reforms, but the traditional prohibition remains the dominant rule. As a result, sponsors, law firms, and lenders typically approach these transactions with conservative, jurisdiction-by-jurisdiction structuring assumptions.

II. The Core Deal Architecture: Two Investment Pathways

Building on the pathways discussed in our prior Sidley Update, current transactions generally fall into one of two categories: (i) equity participation in law firms where expressly permitted by regulation and (ii) MSO or split-practice structures in jurisdictions that continue to prohibit nonlawyer ownership of the practice of law. Most other deal features are best understood as tools used within one of these two pathways.

A. Direct Equity Participation Where Permitted

In jurisdictions such as Arizona or under Utah’s sandbox framework, nonlawyer investors may be permitted to take a direct economic interest in, and/or exert control over, a law firm or legal services entity. Importantly, however, the ethical rules of nonpermissive jurisdictions generally prevent a law firm with nonlawyer ownership from operating outside of its home (permissive) jurisdiction — effectively limiting its growth prospects. These investments are subject to prior regulatory approval, disclosure obligations, and ongoing oversight, and they often include guardrails designed to ensure that legal judgment remains independent.

Even in these jurisdictions, investment transaction documents are typically drafted conservatively. Sponsors often avoid provisions that could be read as allowing investors to direct legal strategy, settlement decisions, or client selection. The regulatory permission to invest does not eliminate reputational risk or the possibility of regulatory reassessment.

B. The MSO / Split-Practice Model

In jurisdictions that prohibit nonlawyer ownership of law firms, the dominant structure is the MSO or split-practice model. Under this approach, the law firm remains owned and controlled by licensed lawyers, while a sponsor-owned MSO owns and operates the nonlegal business platform that supports the firm.

The MSO typically holds or manages all nonlegal assets of the law firm including brand and intellectual property, marketing and advertising infrastructure, technology systems, data and analytics platforms, real estate, cash flows (with some limited exceptions for client funds being held in trust and the like), and nonlawyer personnel. The law firm focuses on providing legal services and retaining authority over professional judgment, ethics compliance, conflicts, and client relationships.

Rather than having an equity stake in the law firm directly, the sponsor will make an equity investment in the MSO and derive its economic return from the MSO’s revenues under a long-term management services agreement (MSA) and related contractual arrangements.

III. MSO Economics and Design: Avoiding Fee-Sharing and Nonlawyer Control Concerns

The MSA is the fulcrum of the MSO structure. Its economic terms must be sufficiently robust to support sponsor underwriting while avoiding impermissible fee sharing or de facto nonlawyer control.

A. Guiding Principle

The central objective is to demonstrate that the MSO is compensated for bona fide nonlegal services at fair market value, not for the provision of legal services or participation in legal fees, and that it performs its role without directing or controlling the professional judgment of the practicing lawyers. While there is no universal safe harbor, the structure, labeling, and optics of the fee arrangement matter and warrant a close review under the applicable jurisdiction’s specific regulatory environment.

B. Common Fee Approaches Viewed as Lower Risk

Market practice increasingly favors fee designs such as these:

• fixed fees for defined services, with scheduled increases
• cost-plus arrangements for operational services, providing reimbursement of documented costs plus an agreed fixed margin
• fair market value pricing, supported by third-party benchmarking or periodic valuation resets
• separately priced components (e.g., technology licensing, call center services, nonlawyer staffing, facilities) rather than a single blended management fee
• operational performance incentives tied to nonlegal metrics such as intake efficiency, speed to contact, or administrative cycle times

These approaches help reinforce the narrative that the MSO is operating a business platform rather than participating in legal fees.

C. Fee Structures That Attract Greater Scrutiny

By contrast, compensation formulas that are variable without clear nonlegal metrics, percentage-based or that otherwise resemble a direct percentage of legal fees, gross receipts, or case recoveries — particularly in contingency-fee practices — are more likely to raise concerns that the MSO is sharing in legal fees. Similarly, compensation contingent on the outcome of legal matters can undermine the distinction between nonlegal services and the practice of law.

Ultimately, the analysis is jurisdiction-specific and fact-driven, but sophisticated deal structuring increasingly emphasizes arm’s-length, service-based economics at fair market value over revenue-participation models.

D. Preserving Professional Independence

The carefully drafted MSA expressly delineates the parties’ roles, allocating responsibility to the law firm for supervision and direction of the legal and legal support services, including the employment and compensation of lawyers, client acceptance or termination, establishment of fee structures, determination of case strategy, and provision of client advice. The MSO’s role is limited to administrative services in support of the business of the firm, such as IT, cybersecurity, bookkeeping, HR administration, facilities and real estate, accounting, and marketing, and its access to client and financial data, trust accounts and client confidential information is appropriately limited. To further this ethical delineation of responsibilities, market practice generally includes a provision affirmatively stating the parties’ intent to comply with applicable ethics rules and directing that the MSA be interpreted in furtherance of such intent. 

IV. Deal Tools Commonly Used Within MSO and ABS Transactions

A. Rollover Equity and Minority Interests

Rollover equity is frequently used to align incentives, bridge valuation gaps, and preserve operational continuity following a transaction. In many transactions, a portion of the selling lawyers roll value into the MSO platform (or, where permitted, into an ABS entity), allowing them to participate in postclosing upside while the law firm itself remains under lawyer ownership and control.

Transactions also frequently involve situations in which one or more majority shareholders sell all or a portion of their interests while other minority shareholders remain invested in the law firm postclosing. In those circumstances, deal structures are often designed with the explicit objective that the remaining minority shareholders are no worse off economically or governancewise as a result of the transaction. This principle is typically addressed through a combination of valuation parity, preservation of existing economic arrangements, indemnification and other make-whole mechanics, and governance protections designed to ensure that the introduction of a sponsor-backed MSO does not dilute minority interests or alter their relative position within the firm.

From a structuring perspective, this often requires careful attention to intercompany economics, distributions, and control rights to avoid creating incentives or cash flow arrangements that favor selling shareholders or the sponsor at the expense of those who remain. Governance rights for minority holders — such as information rights, consent rights over fundamental changes, and protections against adverse amendments to intercompany agreements — are commonly used to reinforce this “no worse off” outcome while remaining consistent with applicable ethical constraints.

B. Leadership and Continuity Arrangements

Because sponsors in MSO-based transactions cannot rely on traditional equity control mechanisms to manage the law practice, many deals incorporate continuity or leadership agreements with designated managing lawyers or management committees. These arrangements are intended to provide operational stability, establish accountability, and facilitate integration with the sponsor-backed platform, while preserving the lawyers’ professional independence.

Leadership and continuity agreements typically set forth performance expectations, reporting obligations, operational benchmarks, and succession planning frameworks. In some transactions, these agreements also include provisions that permit the management company — often controlled by the sponsor — to require the replacement of designated managing lawyers under defined circumstances, such as material breach, persistent failure to meet objective performance standards, or incapacity. In other transactions, instead of the limited ability to replace managing lawyers for a specified reason, the agreement may provide the management company with the option to do so at any time for no specific reason.

Where such replacement rights are included, they are generally drafted with significant care. Market practice generally anchors replacement mechanics in requirements that any successor managing lawyer be duly licensed, qualified, and acceptable under applicable professional responsibility rules. The intent is to provide the sponsor with a measure of continuity and risk mitigation without granting nonlawyers the ability to direct legal strategy, influence professional judgment, or interfere with client relationships.

Properly structured, these arrangements function as an operational safeguard rather than a control mechanism, reinforcing continuity and accountability while respecting the ethical requirement that legal decisions remain within the exclusive province of licensed lawyers.

V. Selecting Appropriate Targets

Not all law firms are equally suitable for private equity investment. For example, plaintiff-side personal injury firms often underwrite better than relationship-driven practices because

• client demand is consistent and can be generated through scalable advertising and digital channels
• intake and conversion metrics can be measured and optimized
• case management can be standardized across large volumes of matters
• revenue is less dependent on individual rainmakers or on relationships with individual lawyers

Firms that already operate with centralized systems, disciplined data tracking, and institutional processes tend to integrate more effectively into sponsor-backed platforms.

VI. The Lender Perspective: Underwriting, Collateral, and Ethics Comfort

When the consideration paid by sponsors in these transactions includes the proceed of debt incurred by the law firm or other applicable law-firm-related party, lenders play a central role in shaping these structures. Their underwriting, collateral, and enforcement decisions must align with both credit fundamentals and ethical constraints.

A. Core Credit Thesis

For MSO transactions, lenders typically focus on whether the value resides in the nonlawyer platform and whether that value can be collateralized and enforced without appearing to control the practice of law. This leads lenders to concentrate on MSO assets, contracts, and cash flows, as well as how the MSA captures such cash flows, rather than on the law firm itself. Because the value of the MSO ultimately depends on the financial performance of the law firm and the retention of the remaining shareholders, lenders may also focus on the treatment of the remaining shareholders in the transaction and their go-forward economic incentives.

B. Loan Parties and Guarantees

Market practice for financing these transactions generally includes all non-law-firm entities — such as the MSO and its parent companies — as borrowers and/or guarantors. These entities typically grant security interests in substantially all of their assets, including the equity interests that the parent companies hold in the MSO and any applicable rights under the intercompany credit facilities, and other related documents, providing lenders with collateral held by these entities while avoiding direct control over legal services.

C. Contract Collateral

Because the MSA and related agreements often represent the economic backbone of the investment transaction, lenders commonly require security interests in, and collateral assignments, of

• the management services agreement
• leadership or continuity agreements
• intercompany debt instruments and security agreements (including any Uniform Commercial Code financing statements filed against the law firm in favor of the MSO)
• at times, key IP and technology licenses

These assignments must be drafted carefully to ensure that lender step-in rights do not translate into control over legal judgment.

D. Asset Migration and Structural Integrity

Lenders frequently require confirmation that nonlegal assets have been transferred into the MSO as a condition to closing (and even if not required as an express condition to the financing, it is often a condition to the underlying acquisition). This supports both credit underwriting and the compliance narrative that the sponsor acquired a business platform rather than the law practice itself.

E. Security Interests in Law Firm Assets

Whether a lender can or should take a security interest in law firm assets is a nuanced, jurisdiction-specific question. While some forms of law firm collateral may be permissible as a commercial law matter, taking such collateral in the context of an MSO-backed transaction can raise regulatory and optics concerns. Further, the remaining shareholders in the law firm may be hesitant to consent to the law firm guaranteeing the debt or granting a security interest in the assets of the law firm to support the debt. Sophisticated lenders often prioritize MSO collateral and approach law firm assets cautiously, with tailored ethics analysis and enforcement limitations, particularly as a security grant may be of limited practical utility in a downside scenario in regulatory environments where control by nonlawyers is prohibited, as a lender’s exercise of remedies against the law firm will be constrained by such prohibition. At the same time, lenders carefully consider the amount of debt permitted to be incurred at the law firm level (as compared to the MSO level, which is subject to restrictive covenants under the loan documentation) to minimize the amount of any structural subordination built into the transaction.

F. Ethics Diligence and Regulatory Comfort

Lenders increasingly conduct independent ethics diligence, often engaging specialized counsel to assess whether the structure is consistent with applicable professional responsibility rules. Credit documentation commonly includes representations, covenants, and notice provisions designed to preserve compliance and address regulatory developments.

G. Enforcement and Workouts

In a default scenario, lenders must be able to enforce remedies without becoming de facto operators of a law practice. Well-structured transactions anticipate this by allowing lenders to enforce against MSO assets and contracts, sell or restructure the platform, and preserve lawyer control over legal services.

Conclusion

Private equity investment in law firms is no longer hypothetical, but it remains highly regulated and structurally complex. The market has converged around two core pathways — direct investment where permitted and MSO structures elsewhere — supplemented by a sophisticated toolkit of contractual and economic arrangements.

Sponsors and lenders that succeed in this space will be those that treat ethical compliance as a core design principle rather than a constraint to be worked around. As regulators, investors, and lenders continue to engage with these models, transaction sophistication — and scrutiny — will only increase. Legal advisers who understand both the regulatory boundaries and the commercial imperatives will be best positioned to guide the next phase of this evolving market.