Mercer Advisors Shifts Strategy with Acquisition of AI-Native Tax Firm Fifteenth

In a decisive move that underscores the evolving requirements of the ultra-high-net-worth (UHNW) market, Denver-based Mercer Advisors has announced the acquisition of Fifteenth, an artificial intelligence-native tax and accounting firm. The deal, announced on November 5, 2026, marks a significant departure from the registered investment advisor’s (RIA) previous growth strategy. While Mercer has historically focused on acquiring established CPA practices to bolster its in-house tax capabilities, the acquisition of Fifteenth signals a transition toward prioritizing proprietary technology as the primary driver of operational scale.

Mercer Advisors, which manages $114 billion in client assets, is positioning this acquisition to address the intensifying demand for integrated, sophisticated tax planning. By bringing both a specialized CPA team and the architects of Fifteenth’s proprietary AI platform into the fold, Mercer is aiming to redefine its service model. The platform was purpose-built to navigate the complexities of stock option exercises, tender offers, and liquidity events—areas of acute need for high-earning professionals in the technology sector.

Tax Demand is Reshaping the Mega-RIA Model

The acquisition of Fifteenth is not an isolated event; it is a response to a fundamental shift within Mercer Advisors’ own client base. Data from the firm reveals that more than 50% of the ultra-high-net-worth clients joining the practice now explicitly request comprehensive tax capabilities as an integrated component of their wealth management experience. This trend is driven by an environment of rising wealth complexity and a rapid, ongoing surge of executive equity and liquidity events among growth-stage companies, particularly in Silicon Valley.

As these clients navigate increasingly intricate financial lives, the traditional model of treating tax preparation as a seasonal, siloed compliance exercise is becoming obsolete. Mercer is responding by embedding tax professionals directly into its advisory structure. As of late 2026, tax professionals account for approximately one in 10 of Mercer’s 1,880 employees. The firm projects this ratio will increase to one in eight by the close of the year.

Cynthia Loh, Chief Platform Officer at Mercer Advisors, emphasized that the decision to acquire Fifteenth was rooted in the proven efficacy of its technology. "What sets Fifteenth apart is that their AI capabilities aren’t theoretical," Loh stated. "They’ve been built and refined through supporting thousands of returns, real numbers that made us excited about bringing their time-tested technology into our organization."

Unlike traditional firms that rely on incremental headcount growth to manage seasonal filing burdens, Fifteenth’s model centers on year-round planning. By pairing continuous, proactive strategy with annual preparation, the firm offers a level of service that aligns with the high-stakes needs of top-tier clients. For Fifteenth’s co-founders, Ankur Dahiya and Laura Moreno—both of whom will join Mercer Advisors—the partnership provides a pathway to scale their technology-first approach to a broader national audience. "We built Fifteenth around a simple idea: even the most complex tax situations shouldn’t have to feel complex for the client," Moreno noted.

A Technology Acquisition as Much as a Talent Deal

The acquisition of Fifteenth stands in stark contrast to Mercer’s previous tax-focused deals, such as the additions of Beach Freeman Lim & Cleland and Glass Jacobson. Those transactions were primarily focused on acquiring established human capital and expanding regional footprints. While those acquisitions were successful in bringing in veteran tax practitioners, the Fifteenth deal represents an evolution toward infrastructure-based growth.

The goal is to leverage technology to handle complex returns with greater speed and precision than a purely headcount-driven model could achieve. For a firm that surpassed the 100-deal milestone in its decade-long acquisition strategy in May 2025, the ability to integrate repeatable, scalable technology is a critical strategic pivot. As Mercer Advisors continues to grow, the ability to increase capacity without a linear increase in staff costs is expected to provide a significant competitive advantage.

Daniel Gourvitch, President of Mercer Advisors, highlighted the importance of this shift, stating, "Our partnership strategy is ultimately about building a better experience for clients, and technology that works in partnership with high-caliber professionals is a significant part of that. Fifteenth fits that model with a tax focus and technology that can be extended to the clients who need it."

This commitment to technical infrastructure is consistent with Mercer’s broader roadmap. The firm has already begun deploying the second generation of "Aspen," its internal AI-enabled advisory platform. By integrating Fifteenth’s tax-specialized tech into the firm’s existing digital environment, Mercer is signaling that artificial intelligence is no longer a peripheral feature—it is becoming the foundational infrastructure of the firm.

Equity Compensation as a Client Acquisition Strategy

Beyond the immediate operational gains, the acquisition of Fifteenth serves as a potent client acquisition strategy. By embedding itself into the financial lives of technology professionals well before a major liquidity event—such as an IPO, merger, or secondary sale—Mercer can establish a deep planning relationship early in the wealth creation cycle.

Many technology executives historically turn to boutique equity compensation specialists or independent tax advisors when faced with the complexity of unvested stock and intricate option structures. By providing these specialized services in-house, Mercer is effectively removing the barrier between tax planning and wealth management, creating a more cohesive, "sticky" relationship with the client. This upstream engagement is a key differentiator in the increasingly crowded competition for high-net-worth business.

AI Becomes Infrastructure at Mercer, Not Just a Feature

The acquisition of Fifteenth is the second major technological advancement announced by the firm in November 2026. Just days prior, on November 3, Mercer Advisors announced a multi-year partnership with Arch, a leading infrastructure layer for private markets.

The Arch platform is designed to automate the collection and routing of data related to alternative investments, such as K-1s, capital calls, and distributions. Since beginning their collaboration in early 2025, the partnership has already yielded substantial results, saving Mercer more than 7,000 operational hours annually and reducing the cost of managing client alternative investments by 40%.

Don Calcagni, Chief Investment Officer at Mercer Advisors, noted that the Arch platform has become essential for providing transparency. "Arch has become a key component of our private investments platform and operations, bringing critical investment data into our central advisory platform and giving advisors and clients real-time visibility into private investments, much like they already have with public markets," Calcagni said.

The strategic integration of these tools—Arch for private market data and Fifteenth for tax and equity compensation—means that the firm’s central Aspen platform is becoming increasingly intelligent and interconnected. With private markets data, sophisticated tax planning, and comprehensive financial planning now flowing through a single, connected infrastructure, Mercer is aiming to provide a seamless experience for its growing roster of ultra-high-net-worth families.

Mercer Advisors, which is majority-owned by a consortium including Oak Hill Capital, Genstar Capital, Altas Partners, and GIC, continues to operate with a national footprint of more than 120 locations. Having been recognized as the top-ranked RIA firm by Barron’s for three consecutive years, the company’s recent technology-focused acquisitions suggest a firm that is looking to cement its leadership position by leveraging scale, technology, and specialized human expertise. As of the latest reporting period, the firm remains focused on building a durable, tech-enabled advisory model that can adapt to the shifting needs of the modern wealthy client.