Mercer Advisors buys AI tax firm Fifteenth to automate work at its $114B RIA
What's the deal? Mercer AdvisorsDealroom has a profile for this one. Try Dealroom →, the Denver-based registered investment advisor with $114 billion in client assets, has acquired FifteenthDealroom has a profile for this one. Try Dealroom →, an AI-native tax and accounting firm. The deal was announced on November 5, 2026, for undisclosed terms.
What does Fifteenth do? Its proprietary AI platform is built to handle stock option exercises, tender offers, liquidity events, and multi-entity filings. The firm serves more than 1,000 professionals, mostly employees of Silicon Valley technology companies navigating equity-driven wealth events.
Why now? More than half of the ultra-high-net-worth clients joining Mercer are seeking tax capabilities as part of a unified offering — a trend the firm ties to rising wealth complexity and a wave of executive equity and liquidity events. Tax professionals now make up about one in 10 of Mercer's roughly 1,880 employees, a ratio it expects to reach one in eight by the end of 2026.
The talent: Fifteenth co-founders Ankur Dahiya and Laura Moreno join Mercer as part of the deal, bringing both a CPA team and the firm's tech builders. Moreno becomes chief tax officer. "Joining Mercer Advisors gives us the opportunity to bring that combination to more clients at greater scale," she said.
What's different? The deal breaks from Mercer's earlier tax acquisitions, which centered on established CPA practices such as Beach Freeman Lim & ClelandDealroom has a profile for this one. Try Dealroom → and Glass Jacobson. Fifteenth is a technology company first, adding infrastructure that extends existing staff rather than headcount alone.
What's the endgame? Mercer said Fifteenth's platform can process complex returns faster and at greater scale than a headcount-driven model. For a firm that passed 100 deals in its decade-long acquisition run in May 2025, buying repeatable technology marks a shift in strategy.
"What sets Fifteenth apart is that their AI capabilities aren't theoretical," said Cynthia Loh, chief platform officer of Mercer Advisors. "They've been built and refined through supporting thousands of returns."
The signal: AI tax-planning software became the highest-impact AI category in RIA practices in 2026. As ultra-wealthy clients demand year-round tax planning, mega-RIAs are buying technology, not just talent, to scale at the top of the market.
Read more: investmentnews.com
Image credit: Generated with Gemini
