Who has been buying Cosmo Bio Company,Limited stock?

5 distinct investors have filed 13 disclosed large-shareholding filings in Cosmo Bio Company,Limited (3386), most recently on 2025-11-18. 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 Cosmo Bio Company,Limited have?

Cosmo Bio Company,Limited has 13 buy-side and 1 sell-side disclosures on record, covering ¥537M ($3.5M) in total reported value, spanning 2021-05-20 to 2025-11-18.

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.

Cosmo Bio Company,Limited 3386

Company

コスモ・バイオ株式会社Cosmo Bio Company,Limited

Investors

Buys

Total Value

¥537M ($3.5M)

Avg Return

+22.93%

Last Filing

2025-11-18

Cosmo Bio Company,Limited (3386) has 13 disclosed large-shareholding filings and 1 disclosed disposals on record, filed by 5 distinct investors. Together those filings cover ¥537M ($3.5M) in reported transaction value. The earliest filing StockDrifts holds for Cosmo Bio Company,Limited is dated 2021-05-20; the most recent is 2025-11-18. Across these filings the average return since disclosure is +22.93%, 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
2025-11-18	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥1,422	-	-
2025-11-18	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	438.3K	¥1,422	-	-
2025-11-18	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	99.7K	¥1,422	-12.6%	¥80M ($516K)
2025-11-18	BUY	Market Buy	株式会社UH5 UH5 Co., Ltd.	passive	6.8K	¥1,422	-	¥10M ($62K)
2025-09-26	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥1,216	-	-
2025-09-26	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	438.3K	¥1,216	+2.2%	¥10M ($66K)
2025-09-26	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	43.3K	¥1,216	+2.2%	¥53M ($342K)
2024-08-08	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	430.0K	¥1,024	+21.4%	¥63M ($404K)
2024-08-08	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥1,024	-	-
2024-06-14	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥1,019	-	-
2024-06-14	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	368.9K	¥1,019	+22.0%	¥73M ($473K)
2024-04-01	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	297.2K	¥1,016	+22.3%	¥63M ($404K)
2024-04-01	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥1,016	-	-
2024-02-15	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	235.4K	¥947	+31.3%	¥57M ($370K)
2024-02-15	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥947	-	-
2023-12-27	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥967	-	-
2023-12-27	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	174.6K	¥967	+28.5%	¥62M ($400K)
2023-11-02	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥977	-	-
2023-11-02	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	110.7K	¥977	+27.2%	¥59M ($381K)
2023-07-14	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	435.9K	¥944	+31.7%	¥10M ($63K)
2023-07-14	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	50.1K	¥944	-	¥47M ($305K)
2023-03-03	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	425.5K	¥989	+25.7%	¥60M ($390K)
2022-12-19	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	364.8K	¥1,013	+22.7%	¥62M ($399K)
2022-04-22	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	303.4K	¥1,006	+23.6%	¥305M ($2.0M)
2021-05-20	SELL	Market Buy	東京中小企業投資育成株式会社 TOKYO SMALL AND MEDIUM BUSINESS INVESTMENT & CONSULTATION CO.,LTD	passive	1.2M	¥1,208	-2.9%	¥73M ($471K)

Frequently asked questions

Who has been buying Cosmo Bio Company,Limited stock?: 5 distinct investors have filed 13 disclosed large-shareholding filings in Cosmo Bio Company,Limited (3386), most recently on 2025-11-18. 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 Cosmo Bio Company,Limited have?: Cosmo Bio Company,Limited has 13 buy-side and 1 sell-side disclosures on record, covering ¥537M ($3.5M) in total reported value, spanning 2021-05-20 to 2025-11-18.
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.

More on this data

Every trade listed above comes from an official regulatory disclosure. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.