AI Advantages in Tax and Accounting Tilt Toward Big Firms

The jostling among tax and accounting firms for early-adopter advantage in generative artificial intelligence is shaping up as an unequal contest between the giants and their smaller rivals.

The Big Four—Ernst & Young, PwC, Deloitte and KPMG—and other top firms are going all in with multibillion-dollar investments to optimize their AI systems on industry-specific data. Their smaller competitors—less able to afford such investments and other costs—may have to make do with off-the-shelf models trained only on public data, like ChatGPT.

“There is a lot of vocabulary information that’s very unique to the specific business,” said Junta Nakai, global head of ...