Mercer Advisors announced an agreement to acquire Fifteenth, an AI-native tax and accounting firm, according to a Vestor Club post dated November 5, 2026. The deal value was not publicly disclosed.
Fifteenth specializes in complex tax situations, particularly equity compensation and stock-related wealth events. The firm combines AI-powered tax technology with experienced accounting professionals to help clients with stock option exercises, tender offers, liquidity events and complex tax filings.
According to the source, Fifteenth serves more than 1,000 professionals, and its technology has supported thousands of tax returns. Co-founders Ankur Dahiya and Laura Moreno are joining Mercer Advisors as part of the transaction.
The source states that the acquisition brings both specialized tax talent and proprietary AI technology into Mercer's wealth management platform. Mercer Advisors, based in Denver, Colorado, manages approximately $114 billion in client assets.
The source describes the deal as an example of how artificial intelligence is changing traditional professional services, noting that Mercer is bringing in technology intended to improve efficiency, expand tax-planning capabilities and support increasingly complex client needs rather than simply acquiring another accounting practice.