Oak Hill-backed Mercer Advisors acquires AI-native tax firm Fifteenth

Mercer Advisors, a national wealth management and financial planning firm, has acquired Fifteenth, an AI-native tax and accounting firm. The deal adds Fifteenth's proprietary platform, built for equity compensation and complex tax situations, to Mercer's family office services. The terms were not disclosed.

Fifteenth's team includes tax professionals from Big Four and other leading firms. The firm offers annual tax preparation alongside year-round planning for stock option exercises, tender offers, liquidity events and multi-entity filings.

Mercer is majority owned by Oak Hill Capital, Genstar Capital, Atlas Partners and GIC. Mercer's chief platform officer said Fifteenth's tools will be integrated with the firm's existing tax infrastructure to expand the capacity of its tax teams.