Who has been buying C.I. Medical Co.,Ltd. stock?

4 distinct investors have filed 3 disclosed large-shareholding filings in C.I. Medical Co.,Ltd. (3540), most recently on 2025-12-12. 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 C.I. Medical Co.,Ltd. have?

C.I. Medical Co.,Ltd. has 3 buy-side and 9 sell-side disclosures on record, covering ¥33.8B ($218.0M) in total reported value, spanning 2021-05-25 to 2025-12-12.

Where does StockDrifts get C.I. Medical 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.

C.I. Medical Co.,Ltd. 3540

Company

株式会社歯愛メディカルC.I. Medical Co.,Ltd.

Investors

Buys

Total Value

¥33.8B ($218.0M)

Avg Return

-0.63%

Last Filing

2025-12-12

C.I. Medical Co.,Ltd. (3540) has 3 disclosed large-shareholding filings and 9 disclosed disposals on record, filed by 4 distinct investors. Together those filings cover ¥33.8B ($218.0M) in reported transaction value. The earliest filing StockDrifts holds for C.I. Medical Co.,Ltd. is dated 2021-05-25; the most recent is 2025-12-12. 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 -0.63%, 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
2025-12-12	BUY	Market Buy	牧寛之 Maki Hiroyuki	activist	5.1M	¥1,492	+0.1%	¥3.7B ($24.0M)
2025-12-12	BUY	unknown	牧寛之 Maki Hiroyuki	other	2.6M	¥1,492	+0.1%	¥3.8B ($24.8M)
2025-10-14	SELL	unknown	清水清人 Kiyoto Shimizu	activist	5.0M	¥1,490	-0.2%	¥27.4B ($176.5M)
2025-10-14	BUY	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	39.3M	¥1,490	+0.2%	¥30.1B ($194.0M)
2025-08-15	BUY	unknown	牧寛之 Maki Hiroyuki	other	2.6M	¥1,526	-2.2%	¥3.9B ($25.4M)
2025-08-13	BUY	unknown	清水清人 Kiyoto Shimizu	activist	42.5M	¥1,511	-1.2%	¥64.2B ($414.4M)
2024-12-03	SELL	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	19.1M	¥967	-54.4%	¥334M ($2.2M)
2024-12-03	SELL	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	19.1M	¥967	-54.4%	¥334M ($2.2M)
2024-12-03	SELL	Market Buy	清水清人 Kiyoto Shimizu	activist	23.4M	¥967	-54.4%	¥445M ($2.9M)
2021-12-07	SELL	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	3.9M	¥1,018	-46.7%	¥38M ($243K)
2021-12-07	SELL	Market Buy	清水清人 Kiyoto Shimizu	activist	4.8M	¥1,018	-46.7%	¥50M ($322K)
2021-09-15	BUY	Market Buy	清水清人 Kiyoto Shimizu	activist	4.8M	¥1,208	+23.6%	¥5.8B ($37.5M)
2021-09-15	BUY	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	3.9M	¥1,208	+23.6%	¥4.8B ($30.7M)
2021-06-15	SELL	Market Buy	清水清人 Kiyoto Shimizu	activist	4.8M	¥1,430	-4.4%	¥123M ($793K)
2021-06-15	SELL	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	3.9M	¥1,430	-4.4%	¥93M ($600K)
2021-06-15	SELL	Market Buy	清水清人 Kiyoto Shimizu	activist	4.8M	¥1,430	-4.4%	¥123M ($793K)
2021-06-09	BUY	Market Buy	清水清人 Kiyoto Shimizu	activist	4.9M	¥1,360	+9.8%	¥6.7B ($43.0M)
2021-06-09	BUY	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	4.0M	¥1,360	+9.8%	¥5.4B ($35.1M)
2021-06-09	BUY	Market Buy	清水清人 Kiyoto Shimizu	activist	4.9M	¥1,360	+9.8%	¥6.7B ($43.0M)
2021-05-25	BUY	Market Buy	清水清人 Kiyoto Shimizu	activist	4.9M	¥1,390	+7.4%	¥6.8B ($43.9M)
2021-05-25	BUY	unknown	エア・ウォーター株式会社 AIR WATER INC.	activist	4.0M	¥1,390	+7.4%	¥5.6B ($35.9M)
2021-05-25	BUY	Market Buy	エア・ウォーター株式会社 AIR WATER INC.	activist	4.0M	¥1,390	+7.4%	¥5.6B ($35.9M)
2021-05-25	BUY	Market Buy	清水清人 Kiyoto Shimizu	activist	4.9M	¥1,390	+7.4%	¥6.8B ($43.9M)

Frequently asked questions

Who has been buying C.I. Medical Co.,Ltd. stock?: 4 distinct investors have filed 3 disclosed large-shareholding filings in C.I. Medical Co.,Ltd. (3540), most recently on 2025-12-12. 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 C.I. Medical Co.,Ltd. have?: C.I. Medical Co.,Ltd. has 3 buy-side and 9 sell-side disclosures on record, covering ¥33.8B ($218.0M) in total reported value, spanning 2021-05-25 to 2025-12-12.
Where does StockDrifts get C.I. Medical 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 C.I. Medical Co.,Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.