AI-Powered Accounting Approval Automation with Accounting and Tax Expertise Expected to Save Approximately 10,000 Hours Annually

TOKYO–Fast Accounting (TOKYO: 5588), an enterprise AI company specializing in accounting automation, today announced that its jointly developed Accounting AI Agent with Ajinomoto Financial Solutions, Inc. (“AFS”), a wholly owned subsidiary of Ajinomoto Co., Inc., has gone live in production at AFS, automating expense reimbursement approvals that were previously handled manually and delivering meaningful efficiency gains without compromising quality.

Ajinomoto Financial Solutions, Inc. (Head office: Chuo-ku, Tokyo; President and Representative Director: Yasushi Takagi) manages centralized finance and accounting operations for Ajinomoto group companies in Japan. Together, AFS and Fast Accounting co-developed an Accounting AI Agent capable of handling accounting and tax judgment tasks autonomously—from login and review of submitted expense claims through to approval or rejection decisions.

This initiative represents a pivotal step in the transformation of accounting operations through AI.

Background

As AFS consolidated the finance and accounting operations of the Ajinomoto Group, it faced a set of structural challenges that were difficult to address through conventional means:

• Tens of thousands of labor hours annually spent reviewing expense reimbursements and invoice processing
• Over-reliance on individual expertise for judgment tasks requiring accounting and tax knowledge
• Difficulty transferring institutional knowledge to new staff
• Quality and scalability constraints that persisted even with BPO (business process outsourcing) support

Fast Accounting had long been developing proprietary AI solutions focused exclusively on accounting, accumulating research into accounting-specialized AI language models well before this engagement began. The two companies joined forces with a shared objective: to build a system capable of making accurate, sustainable accounting judgments at speed—while preserving quality—and to create an AI that goes beyond simple RPA or off-the-shelf generative AI to genuinely own the accounting judgment process itself.

Building the Accounting AI Agent

The project restructured the multi-client accounting approval workflows managed by AFS around AI-native processes. Fast Accounting’s accounting-specialized AI technology—developed in-house—was combined with its proprietary AI-OCR, document processing, and workflow automation capabilities (including Remota and Robota), and integrated with Ajinomoto Group’s specific business rules and institutional knowledge. The result is an end-to-end automated approval workflow—from login through judgment and approval—capable of flexible, knowledge-based decision-making rather than rigid rule-following.

Unlike conventional RPA, the system is not dependent on specific screen layouts or conditions, making it adaptable across clients and use cases. This enables reproducible, high-efficacy automation while keeping verification costs low.

Tasks that previously required four to five minutes per expense claim are now handled automatically through matching of application data against receipt images. For accounting teams processing approximately 10,000 vouchers per month, this translates to an expected reduction of roughly 10,000 labor hours per year. Following its initial go-live within AFS’s own expense operations, the system will be expanded to cover approval workflows for other client companies managed by AFS.

Looking ahead, the companies plan to extend AI-driven judgment to invoice processing workflows as well—covering areas such as data-to-image matching, prepaid expense classification, capital expenditure determination, withholding tax handling, and lease transaction assessment.

Flow Diagram of the AI Agent Deployed at AFS

AI handles judgment; humans focus on internal controls such as post-hoc sample checks

Proprietary Technology That Addresses the Limits of Generative AI

Large language models (LLMs) offer impressive generative capabilities, but they also carry a well-documented risk: hallucination, or the confident generation of factually incorrect outputs. In accounting—where accuracy is non-negotiable—this risk has been a persistent barrier to AI adoption. Even as LLM accuracy improves, eliminating hallucination entirely remains an unsolved problem.

Fast Accounting confronted this challenge directly, drawing on years of accounting-specific AI development. Rather than optimizing for more LLM output, the company prioritized reliable task completion. The result is an AI agent architecture built around clearly defined preconditions, workflows, and acceptance criteria—with LLM capabilities deployed within that structure. By layering its accumulated proprietary technologies, Fast Accounting has delivered an Accounting AI Agent capable of automating the entire accounting approval workflow end-to-end.

93.3% Accuracy Rate

To validate the effectiveness of the Accounting AI Agent—which combines Fast Accounting’s domain-specific accounting and finance logic with LLM capabilities—the companies conducted a head-to-head comparison using identical datasets across three task categories: required field verification on receipts, Japan’s Qualified Invoice System (Invoice System) compliance checks, and tax classification of entertainment expenses.

The Accounting AI Agent achieved an overall accuracy rate of 93.3%, significantly outperforming a standalone LLM, which scored 53.3%. The results demonstrate that in specialized domains, combining domain-specific business logic and rule-based frameworks with AI—rather than relying on LLMs alone—is an effective path to both high accuracy and practical deployability.

Key Features

• In-house developed, accounting-specialized AI that understands and applies accounting standards, tax regulations, and internal corporate policies
• Capable of referencing and learning company-specific operational rules for each client
• Holistic judgment across both application data and supporting documents (receipt and invoice images)
• High accuracy and quality sustained through years of accumulated accounting-domain expertise
• Stable approval processing by the AI agent even during peak periods

Significance and Outlook

This project goes beyond operational efficiency or automation. It represents a fundamental redesign of how accounting work gets done: entrusting AI with judgment calls in accounting and tax that have historically required human expertise; converting ad hoc, person-dependent decisions into reproducible, systematic processes; and rebuilding workflows from a “human-first” model to an “AI-native” one. In that sense, this is nothing less than a transformation of the accounting function itself.

This engagement also gave Fast Accounting a critical opportunity to deploy its accounting AI technology deeply within live enterprise operations, demonstrating both its effectiveness and scalability.

Building on the insights gained, both companies intend to expand the system beyond accounting approvals into additional workflow areas, evolve toward a multi-agent “organizational AI” architecture in which specialized agents collaborate, and ultimately pursue the development of an “Accounting AI Ecosystem” that can be leveraged across companies and corporate groups.

Yasushi Takagi, President and Representative Director of Ajinomoto Financial Solutions, Inc. commented:

“We would like to express our sincere gratitude to the entire team at Fast Accounting for driving this project forward.
“The approval tasks previously handled manually by our BPO partner are now being replaced by AI agent-driven approvals and rejections. This enables us to further standardize these operations, reduce the burden on our BPO partner, and pursue even greater levels of outsourcing and operational sophistication.
“We also wish to acknowledge the meaningful contributions of transcosmos inc.’s Nagasaki BPO Center, our outsourcing partner, and NRI System Techno, Ltd. an equity-method affiliate of the Ajinomoto Group responsible for systems development and maintenance, both of whom participated in and supported this project. Our own staff also contributed through OE activities, including workflow design and the structuring of checklist items. It is through these collective efforts that we reached production go-live. We extend our deepest thanks to everyone involved.”

Keitaro Mori, President and CEO of Fast Accounting, commented:

“We are deeply grateful to the entire team at Ajinomoto Financial Solutions for their partnership throughout this project.
“Accounting and tax represent an area of exceptionally high specialized expertise, and the value AI can bring here has always been clear. At the same time, deploying AI in this domain is not simply a matter of implementing a tool—it requires rebuilding the fundamental assumptions of how work gets done. Reaching production with this project is a significant proof point that this kind of transformation is achievable.
“Through this engagement, we believe accounting AI has entered a stage where it can generate value that extends across companies and industries—laying the foundation for what we see as an ‘Accounting AI Ecosystem.’
“Fast Accounting will continue to accelerate the development and real-world deployment of accounting-specialized AI—with the Accounting AI Agent at its core—contributing to the enhanced international competitiveness of Japanese enterprises.”

About Ajinomoto Financial Solutions, Inc.

As part of our effort to achieve the Ajinomoto Group’s purpose, which is to “Contribute to the well-being of all human beings, our society, and our planet with ‘AminoScience’”, we will provide high level service to our client and be a trusted business partner to them through professional works in the field of finance & accounting.
We respect the individuality of each employee, and on the basis of diversity, equity, and inclusion, we aim to create exciting innovations in the field of finance & accounting, and to achieve mutual growth for both our employees and the company.

Company name: Ajinomoto Financial Solutions, Inc. (Wholly owned subsidiary of Ajinomoto Co., Inc.)
Head office: 15-1, Kyobashi 1-chome, Chuo-ku, Tokyo
Established: April 2020
Representative: Yasushi Takagi, President and Representative Director
URL: https://www.afs.ajinomoto.co.jp/
Business activities:

• Finance and accounting operations for Ajinomoto Co., Inc. and its group companies
• All operations ancillary and related to the preceding section

About Fast Accounting

“Empowering accounting professionals by removing constraints through the Accounting Singularity.”
Fast Accounting develops proprietary AI solutions that automate, reconcile, and validate complex accounting tasks using generative AI and computer vision. Its solutions are adopted by major accounting software vendors and large enterprises in Japan.
By realizing the Accounting Singularity, Fast Accounting aims to address the growing shortage of accounting talent and enable accounting professionals to shift from manual processing to higher-value, strategic financial roles that contribute directly to enterprise value creation.

Media Contact

Ajinomoto Financial Solutions, Inc.
Public Relations
Contact form: https://forms.office.com/r/JHSF5KFQK2

Fast Accounting
Public Relations
E-mail: press@fastaccounting.co.jp

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