# AI beats accountants in speed and accuracy but still needs supervision

> A study finds AI models finish bookkeeping tasks faster and more precisely than CPAs, yet they cannot close the books without human oversight.

Oossa · 2026-10-02 · https://oossa.com/en/ai-beats-accountants-in-speed-and-accuracy-but-still-needs-supervision

A recent study by research firm Mercur (spelled Mercor in the source) compared 12 licensed CPAs with several AI models on a set of bookkeeping tasks. The AI models solved the tasks almost flawlessly, beating the accountants on speed, accuracy and cost. However, the models still could not complete a full set of accounting work without a human supervising the final steps.

## What the test showed

The benchmark used simplified tasks from the APEX Accounting Benchmark, a collection of 160 tasks across 10 simulated companies. The best model, Claude Opus 5.5, met 61.8 % of the grading criteria, followed closely by Fable 5.1 at 61.0 % and GPT‑6 Astra at 57.9 %. In the same test, the average CPA scored about 37 % when working without AI assistance. The study notes that none of the models reached the 60 % threshold needed to close the books on their own.

## Why accountants are still needed

Mercor points out that the benchmark focused on tasks AI does well—finding details and following exact instructions. It left out parts of the job that require human judgment, such as talking with clients, coordinating with colleagues, and applying years of contextual knowledge. Because of these gaps, accountants remain essential for final review and decision‑making, even if AI can handle the bulk of data‑driven work.

## The facts

- The study involved 12 licensed CPAs with an average of 5.5 years of experience.
- Claude Opus 5.5 achieved the highest score, meeting 61.8 % of the grading criteria.
- Fable 5.1 scored 61.0 % and GPT‑6 Astra scored 57.9 % on the same benchmark.
- The average CPA scored about 37 % when working without AI assistance.
- The benchmark contains 160 tasks across 10 simulated companies.

## Why it matters

For small‑business owners, AI can speed up routine bookkeeping and lower costs, but a human accountant is still required to review and finalize the books. This means firms can expect productivity gains, yet they must budget for professional oversight to ensure compliance and accuracy.

## Sources & references

1. [AI beats licensed accountants on speed and accuracy, but still can't close the books without supervision](https://the-decoder.com/ai-beats-licensed-accountants-on-speed-and-accuracy-but-still-cant-close-the-books-without-supervision/) – The Decoder, 2026-10-02

Last updated: 2026-10-02