Basis, a U.S.-based startup founded in 2023, is using OpenAI’s latest models including o3, o3-Pro, GPT-4.1, and GPT-5 to enhance AI agents for accounting firms. These agents automate structured tasks such as reconciliations, journal entries, and financial summaries while providing accountants with full transparency into the decision-making process.

Firms using Basis report up to 30% time savings on average, allowing them to focus more on client advisory work and growth opportunities. The company’s multi-agent architecture assigns the most suitable OpenAI model to each task GPT-5 for complex, high-context workflows, and GPT-4.1 for speed-critical steps. This design allows the system to expand its coverage and accuracy as model capabilities improve.

A key focus for Basis is making automation reviewable. Agents share their assumptions, data sources, and the logic behind each decision so accountants can verify and adjust outputs. GPT-5’s reasoning and parallel tool-calling abilities further support multi-step workflows such as month-end close.

With each new OpenAI release, Basis runs benchmarks on real-world accounting scenarios, assessing both accuracy and clarity of reasoning to decide when agents can take on more responsibilities. Close collaboration with OpenAI has helped refine both model use and workflow design.

Today, Basis supports a significant share of large accounting firms across the U.S., with adoption continuing to grow as trust in its agents increases. Co-founder Mitchell Troyanovsky says the partnership with OpenAI is enabling accountants to delegate more workflows while maintaining oversight and control.