Wealth managers serving families are adding specialised tax technology as equity compensation and liquidity events grow more complex. Mercer Advisors has acquired Fifteenth, an AI-native tax and accounting firm built for equity compensation and complex tax situations, to deepen its integrated family office offering.
The deal brings Fifteenth's proprietary platform and tax team into Mercer Advisors' national wealth management and financial planning partnership. Mercer Advisors says the acquisition strengthens its ability to deliver comprehensive family office services spanning financial planning, tax planning and preparation, estate planning and investment management.
What Fifteenth brings
Fifteenth pairs tax expertise from Big Four and other leading firms with a proprietary AI platform designed for high-complexity tax work. It combines annual tax preparation with year-round planning, helping clients navigate stock option exercises, tender offers, liquidity events and multi-entity filings. The firm has a strong following among employees of Silicon Valley technology companies, and its AI-focused technology builders will join Mercer Advisors.
Ankur Dahiya, chief executive and co-founder of Fifteenth, said the firm combines personalised, high-touch service with modern software, and that joining Mercer Advisors would bring specialised tools already serving more than 1,000 professionals to more families.
Rising demand for tax among UHNW clients
Tax services remain in high demand. Mercer Advisors said more than half of the ultra-high-net-worth clients who join the firm are actively seeking tax capabilities as part of a unified offering, a trend it attributes to rising wealth complexity and a wave of executive equity and liquidity events across fast-growing companies. Tax professionals now make up roughly one in 10 of the firm's employees, a share expected to reach one in eight by the end of 2026.
Cynthia Loh, chief platform officer of Mercer Advisors, said Fifteenth's AI capabilities have been built and refined through supporting thousands of returns, rather than remaining theoretical. As the firm integrates those tools with its existing tax infrastructure, it expects to expand the capacity of its tax teams while keeping the expertise clients expect.
Fifteenth's focus on equity compensation adds depth where tax and wealth planning often intersect, and creates opportunities to engage clients earlier — ahead of a sale, IPO or other major liquidity event, not only at filing time.
Laura Moreno, chief tax officer and co-founder of Fifteenth, said the firm was built around the idea that even complex tax situations should not feel complex for the client, combining technology with the judgement of experienced tax professionals. Joining Mercer Advisors, she said, lets that combination reach more clients at greater scale, and connects existing Fifteenth clients to comprehensive wealth management.
Daniel Gourvitch, president of Mercer Advisors, said the partnership strategy is about building a better client experience, and that technology working alongside high-calibre professionals is a significant part of that. Fifteenth fits the model with a tax focus and technology that can be extended to the clients who need it.
Mercer Advisors has also been investing in AI tools for its advisory teams. In the summer it announced the second generation of Aspen, its AI-enabled platform used by wealth advisory teams for fiduciary family offices.
Founded in 1985 and based in Denver, Mercer Advisors offers fee-based family office services including financial planning, estate and tax planning, insurance, and corporate trustee and trust administration. It has more than 1,880 employees, operates through more than 120 locations and has $114 billion in client assets. It is majority owned by Oak Hill Capital, Genstar Capital, Altas Partners and GIC.
For family offices and UHNW families, the deal underlines how tax capacity and practical AI are becoming core to integrated wealth platforms rather than add-ons.
Source: Mercer Advisors via Business Wire.
This post originally appeared here.
