Building a Book of Business: What Makes a Partner Marketable?

For law firm partners, a strong book of business is more than just a collection of clients, it’s the cornerstone of professional value and long-term career security. In today’s competitive legal market, firms increasingly measure a partner’s marketability by their ability to generate and sustain client relationships. Understanding what goes into building and maintaining that book is critical for attorneys seeking to advance or transition their careers. 

A partner’s marketability often comes down to the strength of their book of business. Firms value attorneys who can demonstrate trusted client relationships, steady revenue, and the ability to generate new opportunities while retaining existing work. A portable book shows not only legal expertise but also proven business development skills, qualities that make a partner indispensable. In the sections ahead, we’ll break down the core factors that make a book of business both valuable and sustainable. 

Why a Portable Book of Business Matters 

A partner’s portable book of business, a portfolio of clients likely to follow them to a new firm, is foundational to both career security and marketability. Law firms often look for lateral partner candidates with a portable book ranging from $1 to $3 million, especially in competitive legal centers. This kind of book not only provides negotiating power but also offers the firm a real return on hiring investment. 

That said, portability isn’t perfect. Data shows that while candidates claim about 57% client portability, the actual rate tends to be closer to 35%, reflecting the difficulty of shifting long-standing client loyalties. Still, partners with substantial and convincing client relationships remain highly desirable. Even smaller books, when profitable or deeply tied to niche clients, can set candidates apart in the marketplace.

Building a Strong Book of Business 

For partners, a book of business is more than a revenue stream. A strong book signals to firms that your value goes beyond technical expertise, demonstrating that clients choose you for trust, judgment, and results. Building such a book requires a deliberate approach to client development and relationship management. 

• Prioritize Direct Client Relationships: Clients who view you, not just your firm, as their advisor are the backbone of a portable practice. Regular communication, responsiveness, and a personal investment in their success help establish loyalty that extends beyond any single institution. 
• Target Clients Who Value You Specifically: Not every client relationship is equally portable. Focus on cultivating clients who appreciate your unique contributions, whether it’s industry knowledge, strategic insight, or responsiveness. These clients are more likely to follow you if you make a move. 
• Diversify Your Client Base: Relying too heavily on a single client or sector creates risk. A well-rounded client portfolio across industries, company sizes, and geographies not only increases stability but also protects you from downturns in one area. Diversification also shows firms that your book is resilient and sustainable. 
• Stay in Touch Beyond Transactions: The most successful partners nurture relationships even when no deal or case is pending. Thoughtful follow-ups, sharing industry updates, or offering informal guidance reinforce your role as a trusted advisor rather than a transactional lawyer. These touchpoints keep you top-of-mind when future matters arise. 
• Take Ownership of Origination Credit: Within firms, origination credit is a key measure of a partner’s contribution. Ensuring you receive proper recognition for bringing in and managing client relationships is essential to demonstrating your marketability. It not only reflects your current influence but also helps preserve the portability of those relationships. 
• Maintain Ethical Boundaries: While business development is critical, it should always be balanced with professional responsibility. Adhering to ethical guidelines, especially regarding client solicitation and confidentiality, builds credibility and long-term trust. A reputation for integrity can often be as valuable as the size of your book. 

Other Factors That Can Impact Partner Marketability 

Although a book of business is central to partner value, it’s not the only factor firms weigh. A partner’s ability to bring complementary skills, reputation, and leadership qualities can significantly influence marketability and long-term success. 

• Specialized Expertise and Reputation: Lawyers with recognized authority in high-demand practice areas, such as data privacy, energy, or cross-border transactions, are often attractive to firms even if their books aren’t large. A strong personal brand, bolstered by speaking engagements, publications, or bar association leadership, signals to clients and firms alike that you’re a thought leader worth investing in. 
• Leadership and Team-Building Skills: Firms seek partners who can not only deliver client work but also contribute to firm culture. Partners who mentor associates, foster collaboration, and drive cross-selling opportunities strengthen the entire institution. These skills demonstrate staying power and make a lateral move more appealing. 
• Adaptability to Market Trends: The legal industry is constantly evolving, shaped by new technologies, client expectations, and regulatory changes. Partners who anticipate and adapt to these shifts, such as embracing AI tools, alternative fee structures, or ESG-related services, position themselves as forward-thinking leaders. Adaptability shows firms that you bring more than a book of business; you bring a vision for the future. 
• Geographic or Market Knowledge: Regional or industry-specific insight can dramatically increase partner value. A lawyer with deep connections in an emerging business hub or specialized industry sector can open doors to client opportunities that firms might not otherwise access. This knowledge not only enhances portability but also underscores your strategic importance. 

In today’s competitive legal market, a strong book of business paired with professional credibility is what makes partners truly marketable. By investing in client relationships, diversifying your portfolio, and honing leadership skills, you can position yourself for long-term success and flexibility. Momentum Search Partners works with attorneys at every stage of their careers to identify the right opportunities and firms that value their contributions. If you’re ready to strengthen your career trajectory, contact us to guide the way.