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Mutex raises ¥281.6M in Series A funding to expand its AI-powered medical billing SaaS, Reze, with participation from MTI Co., Ltd., MEDIPAL Innovation Investment Limited Partnership, and Nippon Management Co., Ltd.

PRIVATEOct 05, 2026

Amount Raised

¥282 Million

Round Type

Series A

BunkyoInformation TechnologySoftwareHealth CareArtificial IntelligenceMachine LearningSaaS

Investors

Nippon Management Co., Ltd.MEDIPAL Innovation Investment Limited PartnershipMTI Co., Ltd.

Description

Mutex, a Tokyo-based health-tech startup specializing in medical claims processing automation, has raised 281.6 million yen in a Series A funding round. This latest investment will be used to expand the adoption of its AI-powered medical billing SaaS, Reze, among medical institutions. Funds will also support product development for the complete automation of medical claims processing workflows. Mutex's innovative solutions aim to reduce administrative burdens and improve operational efficiency in healthcare facilities.

Quick answer

Mutex raised ¥282 Million in a Series A round, dated October 5, 2026. Investors: Nippon Management Co., Ltd., MEDIPAL Innovation Investment Limited Partnership and MTI Co., Ltd. Mutex is based in Bunkyo, Tokyo, Japan.

How much did Mutex raise?
Mutex raised ¥282 Million in a Series A round on October 5, 2026.
Who invested in Mutex?
Nippon Management Co., Ltd., MEDIPAL Innovation Investment Limited Partnership and MTI Co., Ltd. are named as investors in this round.
What does Mutex do?
Mutex is a software development company focused on AI-powered solutions for medical institutions.
Where is Mutex based and how big is it?
Mutex is based in Bunkyo, Tokyo, Japan. Fundz records about 11 employees.
Who are the decision-makers at Mutex?
Fundz holds 2 contacts at Mutex. Names and contact details are shown to Fundz members.

Source: Fundz verified event record.

Who else raised in SaaS and Software around the same time

Companies in the same sectors as Mutex that raised within 45 days of this round, from Fundz verified event records.

  • Axle raised $9M on November 12, 2026.
  • Kindo raised $30M on November 12, 2026.
  • Agent F raised $4M (Pre-Seed) on November 10, 2026.
  • Mercor raised $750M (Series D) on November 10, 2026.
  • Sumary raised $25M (Seed) on November 10, 2026.
  • Laza Medical raised $160M (Series B) on November 4, 2026.

Who to call at Mutex, and when

A new round usually means Mutex is about to hire and buy. The teams that reach out first get the meeting.

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Company Information

Company

Mutex

Location

Bunkyo, Tokyo, Japan

About

Mutex is a software development company focused on AI-powered solutions for medical institutions. Its flagship product, Reze, is a SaaS platform designed to help medical institutions automate claim processing and improve operational management. By leveraging generative AI and machine learning, Reze simplifies administrative tasks and optimizes revenue for medical departments. Founded in 2022 and headquartered in Tokyo, Japan, Mutex aims to drive digital transformation in the healthcare sector.

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Funding Insights

What this usually means
Typical timeline to Series B
Series A companies typically raise their next round in 10-18 months

Mutex raised. Fundz records a round at a median of 3.6 minutes from the SEC filing, with the decision-maker attached.

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