AI models now outperform licensed CPAs on speed and accuracy in accounting tasks, Mercor study finds

A study by Mercor reveals that artificial intelligence models now outperform licensed CPAs in speed and accuracy on structured bookkeeping tasks, solving them almost flawlessly. While Claude Opus 5.5 leads the APEX Accounting Benchmark with 61.8 percent accuracy, no model can fully solve nearly 60 percent of the tasks. Because the study excludes key human skills like client communication and long-term context, experts emphasize that AI cannot close books without human oversight.

AI performance compared to CPAs

• ▪Eighteen months prior to the Mercor study, the best artificial intelligence models scored below the 37 percent average of licensed CPAs on simplified accounting tasks.
• ▪A study by Mercor found that artificial intelligence models are faster, significantly cheaper, and solve structured bookkeeping tasks almost flawlessly, outperforming 12 licensed CPAs who averaged 37 percent accuracy.

The APEX Accounting Benchmark

• ▪On the full APEX Accounting Benchmark, Claude Opus 5.5 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 stated that no artificial intelligence model fully solved almost 60 percent of the tasks in the APEX Accounting Benchmark.
• ▪The full APEX Accounting Benchmark consists of 160 tasks across 10 simulated companies, developed by more than 40 professionals with an average of 11 years of experience.

Limitations of the study's scope

• ▪Mercor noted that the study's tasks specifically tested areas where artificial intelligence excels, such as locating details and following precise instructions.
• ▪The Mercor study on artificial intelligence in accounting omitted key professional responsibilities, including client communication, colleague collaboration, and utilizing long-term contextual knowledge.

Continued necessity of human accountants

• ▪Mercor concluded that artificial intelligence models cannot close financial books without human oversight.
• ▪Mercor stated that human accountants cannot be replaced by artificial intelligence.

Debatable claims

• ▪Accounting firms should replace junior staff with AI models for bookkeeping
• ▪AI's superior technical performance undermines the value of traditional CPA credentials
• ▪AI models can safely perform structured bookkeeping without human oversight