Parthenon Group , a 23-year-old Boston consulting firm founded by former Bain & Co. executives, has agreed to be acquired by Ernst & Young , in the latest deal among the “big four” accounting giants to expand their advisory services.
The deal, the price of which was not disclosed, would mark the end of independence for Parthenon, a boutique firm cofounded in 1991 by Bill Achtmeyer and John Rutherford. The firm employs 350 people and had revenue in excess of $80 million in 2013.
Achtmeyer, Parthenon’s chairman and managing partner, said the firm was not under any pressure to sell. But its 33 partners voted unanimously to merge into New York-based Ernst & Young, both to deepen Parthenon’s ability to compete and to position it financially for the retirement of senior partners in the future.
“It’s given us a really interesting opportunity that we couldn’t have dreamed of doing by ourselves. And it certainly vastly increases the level of growth we could see,’’ said Achtmeyer, 59.
Parthenon has experienced strong growth in recent years, Achtmeyer said, and attracted more than one suitor.
The deal follows Deloitte Consulting’s 2012 acquisition of another prominent local consulting firm, Monitor Group, founded by a Harvard Business School professor, Michael Porter. Monitor was bankrupt at the time, however.
Achtmeyer said that Ernst & Young will maintain the Parthenon brand and expand it by moving the accounting giant’s Commercial Advisory Services business under the same name. Achtmeyer will oversee the combined group from Boston, with offices around the world.
All of Parthenon’s partners have agreed to stay on for at least four years, with financial incentives to do so.
Achtmeyer acknowledged there could be overlap in administrative jobs under the new regime but said there are no immediate plans for job cuts.
“We intentionally negotiated that no one would leave Parthenon upon consummation of the transaction,’’ he said.
Ernst & Young’s global vice chairman, Pip McCrostie, said in a statement that the transaction was “a great match on many levels,’’ including Parthenon’s reach in the education sector.
Parthenon does strategic consulting for clients from for-profit universities to the Boston public school system. It also does due diligence in private equity transactions and advises chief executives on how to grow companies and direct strategy.
Parthenon positions itself as a nimbler choice than the giants — Bain, Boston Consulting Group, and McKinsey & Co. And the big accounting firms are looking to build their capabilities in strategic advice.
“To be competitive, they really need to move into the strategy side,’’ said Richard Harrington, a member of Parthenon’s advisory committee and a former client of the firm when he was chairman of the media conglomerate Thomson Corp.
Don Bramley, a former Parthenon partner who is now a managing director at the private equity firm Audax Group in Boston, said the key for Parthenon will be keeping its culture of collegiality and hard work inside an accounting and consulting behemoth.
“The beauty of the culture is the fact that [it] is collegial. It’s a fun place to work,’’ Bramley said. “That’s what Bill’s been able to build over the years. Ensuring that continues, going forward, is going to be very important to the success of Parthenon inside Ernst & Young.’’
Achtmeyer said he is hopeful the firm’s new owner will leave Parthenon’s essence intact. “They’ve shown a lot more entrepreneurial zeal than I would have expected,’’ he said.