Who has been buying JMACS Japan Co., Ltd. stock?

3 distinct investors have filed 15 disclosed large-shareholding filings in JMACS Japan Co., Ltd. (5817), most recently on 2025-08-01. Each filer, their role, the number of shares and the price at filing are listed in the table on this page.

How many insider filings does JMACS Japan Co., Ltd. have?

JMACS Japan Co., Ltd. has 15 buy-side and 5 sell-side disclosures on record, covering ¥1.7B ($11.2M) in total reported value, spanning 2024-05-28 to 2025-08-01.

Where does StockDrifts get JMACS Japan Co., Ltd. insider data?

From EDINET large-shareholding (5%+) reports — the official filing system run by the Financial Services Agency (Japan). StockDrifts parses each disclosure and matches it to daily price history; the original filings remain available directly from EDINET.

Do insider buys in Japanese stocks predict returns?

Not uniformly. StockDrifts scored 101,000+ Japanese large-shareholding filings on fixed 12-month forward returns and found the predictive power concentrated in specific filer types and filing patterns rather than spread evenly across all disclosures.

JMACS Japan Co., Ltd. 5817

Company

JMACS株式会社JMACS Japan Co., Ltd.

Investors

Buys

Total Value

¥1.7B ($11.2M)

Avg Return

+201.36%

Last Filing

2025-08-01

JMACS Japan Co., Ltd. (5817) has 15 disclosed large-shareholding filings and 5 disclosed disposals on record, filed by 3 distinct investors. Together those filings cover ¥1.7B ($11.2M) in reported transaction value. The earliest filing StockDrifts holds for JMACS Japan Co., Ltd. is dated 2024-05-28; the most recent is 2025-08-01. All of it is parsed from EDINET large-shareholding (5%+) reports, the official disclosure system operated by the Financial Services Agency (Japan). Across these filings the average return since disclosure is +201.36%, measured from each filing date to the latest available close.

Price & insider activity (12 months)

Recent filings

Date	Type	Source	Insider	Purpose	Shares	Price at filing	Return	Value
2025-08-01	SELL	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	255.7K	¥486	-240.5%	¥67M ($430K)
2025-06-20	SELL	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	393.4K	¥451	-267.0%	¥120M ($773K)
2024-10-11	SELL	Market Buy	植村瑠美 Rumi Uemura	activist	125.8K	¥549	-201.5%	¥16M ($105K)
2024-10-11	SELL	unknown	植村瑠美 Rumi Uemura	activist	125.8K	¥549	-201.5%	¥16M ($105K)
2024-10-11	SELL	unknown	植村瑠美 Rumi Uemura	activist	125.8K	¥549	-201.5%	¥16M ($105K)
2024-10-11	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	1.6M	¥549	+201.5%	¥534M ($3.4M)
2024-10-11	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	1.6M	¥549	+201.5%	¥534M ($3.4M)
2024-10-11	BUY	Market Buy	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	1.6M	¥549	+201.5%	¥534M ($3.4M)
2024-10-10	BUY	Market Buy	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	534.7K	¥542	+205.3%	¥509K ($3K)
2024-10-10	BUY	Market Buy	植村瑠美 Rumi Uemura	strategic	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	Market Buy	植村瑠美 Rumi Uemura	activist	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	79.5K	¥542	+205.3%	¥7M ($46K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	Market Buy	植村瑠美 Rumi Uemura	activist	125.8K	¥542	+205.3%	¥25M ($162K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	strategic	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	66.0K	¥542	+205.3%	¥36M ($231K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	79.5K	¥542	+205.3%	¥7M ($46K)
2024-10-10	BUY	unknown	植村瑠美 Rumi Uemura	activist	125.8K	¥542	+205.3%	¥25M ($162K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	538.7K	¥542	+205.3%	¥1M ($7K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	536.7K	¥542	+205.3%	¥291M ($1.9M)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	536.6K	¥542	+205.3%	¥509K ($3K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	535.7K	¥542	+205.3%	¥509K ($3K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	534.7K	¥542	+205.3%	¥509K ($3K)
2024-10-10	BUY	Market Buy	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	538.7K	¥542	+205.3%	¥1M ($7K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	536.6K	¥542	+205.3%	¥509K ($3K)
2024-10-10	BUY	unknown	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	536.7K	¥542	+205.3%	¥291M ($1.9M)
2024-10-10	BUY	Market Buy	日電ホールディングス株式会社 Nichiden Holdings Co., Ltd.	activist	535.7K	¥542	+205.3%	¥509K ($3K)
2024-08-29	BUY	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	533.7K	¥570	+190.3%	¥74M ($476K)
2024-06-28	BUY	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	404.5K	¥581	+184.8%	¥45M ($292K)
2024-06-19	BUY	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	326.6K	¥570	+190.3%	¥43M ($274K)
2024-05-28	BUY	Market Buy	本多敏行 HONDA TOSHIYUKI	passive	252.0K	¥538	+207.6%	¥136M ($875K)

Frequently asked questions

Who has been buying JMACS Japan Co., Ltd. stock?: 3 distinct investors have filed 15 disclosed large-shareholding filings in JMACS Japan Co., Ltd. (5817), most recently on 2025-08-01. Each filer, their role, the number of shares and the price at filing are listed in the table on this page.
How many insider filings does JMACS Japan Co., Ltd. have?: JMACS Japan Co., Ltd. has 15 buy-side and 5 sell-side disclosures on record, covering ¥1.7B ($11.2M) in total reported value, spanning 2024-05-28 to 2025-08-01.
Where does StockDrifts get JMACS Japan Co., Ltd. insider data?: From EDINET large-shareholding (5%+) reports — the official filing system run by the Financial Services Agency (Japan). StockDrifts parses each disclosure and matches it to daily price history; the original filings remain available directly from EDINET.
Do insider buys in Japanese stocks predict returns?: Not uniformly. StockDrifts scored 101,000+ Japanese large-shareholding filings on fixed 12-month forward returns and found the predictive power concentrated in specific filer types and filing patterns rather than spread evenly across all disclosures.

Source filings

Every trade listed above is disclosed in EDINET large-shareholding (5%+) reports, filed with the Financial Services Agency (Japan). View the original EDINET filings for JMACS Japan Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.