AI beats licensed accountants on speed and accuracy, but still can't close the books without supervision

A Mercor study has found that current AI models outperform licensed CPAs on structured accounting tasks in both speed and accuracy, according to the company. In the study, 12 licensed CPAs with an average of five and a half years of experience worked through simplified tasks from the APEX Accounting Benchmark.

Eighteen months ago, the best models scored below the accountants' average of about 37 percent, but today they solve the same tasks almost flawlessly, the study says.

The full APEX Accounting Benchmark is much larger, with 160 tasks across 10 simulated companies. It was built by more than 40 professionals who average 11 years of experience. Claude Opus 5.5 currently leads with 61.8 percent of grading criteria met, followed by Fable 5.1 at 61.0 percent and GPT-6 Astra at 57.9 percent.

Mercor says no model fully solved almost 60 percent of the tasks, and that AI models cannot close the books without oversight yet.

Mercor also acknowledges the study's tasks test what AI does best: hunting down details and following instructions precisely. The study left out key parts of the job, such as talking with clients, checking in with colleagues, and drawing on context built up over years. Mercor says that is why accountants cannot be replaced, though it expects major productivity gains across the industry.