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

10 distinct investors have filed 11 disclosed large-shareholding filings in Japan Insulation Co., Ltd. (5368), most recently on 2025-12-22. 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 Japan Insulation Co., Ltd. have?

Japan Insulation Co., Ltd. has 11 buy-side and 20 sell-side disclosures on record, covering ¥962M ($6.2M) in total reported value, spanning 2021-04-07 to 2025-12-22.

Where does StockDrifts get Japan Insulation 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.

Japan Insulation Co., Ltd. 5368

Company

日本インシュレーション株式会社Japan Insulation Co., Ltd.

Investors

Buys

Total Value

¥962M ($6.2M)

Avg Return

+22.54%

Last Filing

2025-12-22

Japan Insulation Co., Ltd. (5368) has 11 disclosed large-shareholding filings and 20 disclosed disposals on record, filed by 10 distinct investors. Together those filings cover ¥962M ($6.2M) in reported transaction value. The earliest filing StockDrifts holds for Japan Insulation Co., Ltd. is dated 2021-04-07; the most recent is 2025-12-22. 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 +22.54%, 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
2025-12-22	SELL	Market Buy	株式会社UH Partners 2	unknown	0	¥1,055	-13.1%	-
2025-12-22	SELL	Market Buy	光通信株式会社	passive	359.7K	¥1,055	-13.1%	¥429M ($2.8M)
2025-11-18	SELL	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	444.2K	¥990	-20.5%	¥91M ($584K)
2025-11-18	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	2.6K	¥990	+20.5%	¥3M ($17K)
2025-10-06	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	2.6K	¥996	+19.8%	¥3M ($17K)
2025-10-06	SELL	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	535.9K	¥996	-19.8%	¥88M ($571K)
2025-08-27	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	2.6K	¥1,044	+14.3%	¥201M ($1.3M)
2025-08-27	SELL	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	624.3K	¥1,044	-14.3%	¥26M ($170K)
2025-01-15	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	68.4K	¥880	+35.6%	¥51M ($326K)
2025-01-15	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	649.5K	¥880	+35.6%	¥26M ($168K)
2024-07-29	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	strategic	134.0K	¥999	+19.4%	¥134M ($864K)
2024-07-29	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	349.0K	¥999	+19.4%	¥349M ($2.2M)
2024-07-22	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	10.9K	¥1,027	+16.2%	¥11M ($72K)
2024-07-22	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	619.6K	¥1,027	+16.2%	¥90M ($583K)
2023-12-22	SELL	unknown	三井住友DSアセットマネジメント株式会社 Sumitomo Mitsui DS Asset Management Company, Limited	passive	285.0K	¥911	-30.9%	¥14M ($92K)
2023-12-22	BUY	unknown	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	67.0K	¥911	+30.9%	¥61M ($394K)
2023-12-22	BUY	unknown	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	500	¥911	+30.9%	¥13M ($82K)
2022-11-30	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	10.9K	¥813	+46.7%	¥9M ($57K)
2022-11-30	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	532.2K	¥813	+46.7%	¥78M ($502K)
2022-11-25	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	715.8K	¥813	-46.7%	¥228M ($1.5M)
2022-11-25	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	715.8K	¥813	-46.7%	¥228M ($1.5M)
2022-11-25	SELL	unknown	大橋健一 Kenichi Ohashi	activist	492.8K	¥813	-46.7%	¥122M ($786K)
2022-11-25	SELL	unknown	大橋健一 Kenichi Ohashi	activist	492.8K	¥813	-46.7%	¥122M ($786K)
2022-08-23	BUY	unknown	大橋健一 Kenichi Ohashi	activist	642.8K	¥907	+31.5%	¥583M ($3.8M)
2022-08-23	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	995.8K	¥907	-31.5%	¥135M ($871K)
2022-08-23	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	995.8K	¥907	-31.5%	¥135M ($871K)
2022-08-23	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	1.0M	¥907	-31.5%	¥118M ($759K)
2022-08-23	BUY	unknown	大橋健一 Kenichi Ohashi	activist	642.8K	¥907	+31.5%	¥583M ($3.8M)
2022-08-23	BUY	unknown	大橋健一 Kenichi Ohashi	activist	642.8K	¥907	+31.5%	¥583M ($3.8M)
2022-07-19	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	436.4K	¥874	+36.5%	¥381M ($2.5M)
2022-05-30	SELL	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	strategic	134.0K	¥866	-37.8%	¥84M ($540K)
2022-05-30	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	349.0K	¥866	+37.8%	¥302M ($1.9M)
2022-04-05	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	1.1M	¥900	-32.6%	¥92M ($597K)
2022-04-05	SELL	unknown	大橋健一 Kenichi Ohashi	activist	642.8K	¥900	-32.6%	¥24M ($157K)
2021-11-30	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	349.0K	¥991	+20.4%	¥346M ($2.2M)
2021-11-30	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	230.5K	¥991	+20.4%	¥96M ($618K)
2021-11-15	SELL	unknown	大橋健一 Kenichi Ohashi	activist	669.5K	¥999	-19.4%	¥35M ($224K)
2021-11-15	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	1.2M	¥999	-19.4%	¥35M ($224K)
2021-11-15	SELL	unknown	大橋ゆふみ Yufumi Ohashi	activist	1.2M	¥999	-19.4%	¥35M ($224K)
2021-11-15	SELL	unknown	大橋健一 Kenichi Ohashi	activist	669.5K	¥999	-19.4%	¥35M ($224K)
2021-05-26	BUY	Market Buy	大阪中小企業投資育成株式会社 Osaka Small and Medium Business Investment & Consultation Co.,Ltd	passive	872.4K	¥990	+20.5%	¥864M ($5.6M)
2021-04-07	BUY	unknown	三井住友DSアセットマネジメント株式会社 Sumitomo Mitsui DS Asset Management Company, Limited	passive	300.1K	¥1,148	+3.9%	¥345M ($2.2M)
2021-04-07	BUY	unknown	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	67.0K	¥1,148	+3.9%	¥77M ($496K)
2021-04-07	BUY	unknown	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	73.0K	¥1,148	+3.9%	¥84M ($541K)

Frequently asked questions

Who has been buying Japan Insulation Co., Ltd. stock?: 10 distinct investors have filed 11 disclosed large-shareholding filings in Japan Insulation Co., Ltd. (5368), most recently on 2025-12-22. 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 Japan Insulation Co., Ltd. have?: Japan Insulation Co., Ltd. has 11 buy-side and 20 sell-side disclosures on record, covering ¥962M ($6.2M) in total reported value, spanning 2021-04-07 to 2025-12-22.
Where does StockDrifts get Japan Insulation 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 Japan Insulation Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.