Who has been buying SEIKOH GIKEN Co., Ltd. stock?

11 distinct investors have filed 8 disclosed large-shareholding filings in SEIKOH GIKEN Co., Ltd. (6834), most recently on 2025-10-09. 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 SEIKOH GIKEN Co., Ltd. have?

SEIKOH GIKEN Co., Ltd. has 8 buy-side and 16 sell-side disclosures on record, covering ¥5.1B ($32.6M) in total reported value, spanning 2021-12-02 to 2025-10-09.

Where does StockDrifts get SEIKOH GIKEN 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.

SEIKOH GIKEN Co., Ltd. 6834

Company

株式会社精工技研SEIKOH GIKEN Co., Ltd.

Investors

Buys

Total Value

¥5.1B ($32.6M)

Avg Return

+829.92%

Last Filing

2025-10-09

SEIKOH GIKEN Co., Ltd. (6834) has 8 disclosed large-shareholding filings and 16 disclosed disposals on record, filed by 11 distinct investors. Together those filings cover ¥5.1B ($32.6M) in reported transaction value. The earliest filing StockDrifts holds for SEIKOH GIKEN Co., Ltd. is dated 2021-12-02; the most recent is 2025-10-09. 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 +829.92%, 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
2025-10-09	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥10,170	+209.2%	¥6.7B ($42.9M)
2025-10-09	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥10,170	+209.2%	¥6.7B ($42.9M)
2025-10-09	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥10,170	+209.2%	¥3.4B ($21.7M)
2025-10-09	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥10,170	+209.2%	¥3.4B ($21.7M)
2025-10-06	BUY	Market Buy	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	546.8K	¥9,630	+226.6%	¥422M ($2.7M)
2025-10-06	BUY	Market Buy	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	2.9K	¥9,630	+226.6%	¥28M ($180K)
2025-10-06	BUY	Market Buy	野村證券株式会社 Nomura Securities Co.,Ltd.	other	70.5K	¥9,630	+226.6%	¥53.0B ($342.1M)
2025-09-09	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥8,410	+274.0%	¥5.5B ($35.5M)
2025-09-09	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥8,410	+274.0%	¥5.5B ($35.5M)
2025-09-09	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥8,410	+274.0%	¥5.5B ($35.5M)
2025-09-09	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥8,410	+274.0%	¥2.8B ($17.9M)
2025-09-09	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥8,410	+274.0%	¥2.8B ($17.9M)
2025-09-09	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥8,410	+274.0%	¥2.8B ($17.9M)
2025-02-07	BUY	negotiated	細江宣明 Nobuaki Hosoe	activist	80.7K	¥5,060	+521.5%	¥408M ($2.6M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	都丸沙希 Saki Tomaru	activist	215.0K	¥5,060	+521.5%	¥1.1B ($7.0M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	623.0K	¥5,060	+521.5%	¥3.2B ($20.3M)
2025-02-07	BUY	Market Buy	有限会社光研 Kouken Co., Ltd.	activist	623.0K	¥5,060	+521.5%	¥3.2B ($20.3M)
2025-02-07	BUY	negotiated	細江宣明 Nobuaki Hosoe	activist	80.7K	¥5,060	+521.5%	¥408M ($2.6M)
2025-02-07	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	623.0K	¥5,060	+521.5%	¥3.2B ($20.3M)
2025-02-07	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	594.5K	¥5,060	+521.5%	¥3.0B ($19.4M)
2025-02-07	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	654.5K	¥5,060	+521.5%	¥302M ($2.0M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	694.0K	¥5,060	+521.5%	¥3.5B ($22.7M)
2025-02-07	BUY	negotiated	都丸沙希 Saki Tomaru	activist	215.0K	¥5,060	+521.5%	¥1.1B ($7.0M)
2025-02-07	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	675.5K	¥5,060	-521.5%	¥1.1B ($7.0M)
2025-02-07	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	460.5K	¥5,060	-521.5%	¥1.1B ($7.0M)
2025-02-07	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	890.5K	¥5,060	+521.5%	¥4.5B ($29.1M)
2025-02-07	SELL	negotiated	細江由紀子 Yukiko Hosoe	activist	681.5K	¥5,060	-521.5%	¥1.4B ($9.1M)
2025-02-07	SELL	negotiated	細江由紀子 Yukiko Hosoe	activist	960.5K	¥5,060	-521.5%	¥1.3B ($8.1M)
2025-02-07	BUY	negotiated	細江由紀子 Yukiko Hosoe	activist	882.5K	¥5,060	+521.5%	¥4.5B ($28.8M)
2025-02-07	BUY	Market Buy	細江由紀子 Yukiko Hosoe	activist	1.2M	¥5,060	+521.5%	¥1.7B ($10.7M)
2025-02-07	BUY	negotiated	細江由紀子 Yukiko Hosoe	activist	882.5K	¥5,060	+521.5%	¥4.5B ($28.8M)
2025-02-07	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	675.5K	¥5,060	-521.5%	¥1.1B ($7.0M)
2025-02-07	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	460.5K	¥5,060	-521.5%	¥1.1B ($7.0M)
2025-02-07	BUY	negotiated	都丸由美子 Yumiko Tomaru	activist	890.5K	¥5,060	+521.5%	¥4.5B ($29.1M)
2024-12-20	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	583.5K	¥5,800	+442.2%	¥3.4B ($21.8M)
2024-12-20	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥5,800	+442.2%	¥3.8B ($24.5M)
2024-12-20	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥5,800	+442.2%	¥3.8B ($24.5M)
2024-12-20	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	583.5K	¥5,800	+442.2%	¥3.4B ($21.8M)
2024-12-20	SELL	negotiated	細江由紀子 Yukiko Hosoe	activist	282.5K	¥5,800	-442.2%	¥866M ($5.6M)
2024-12-20	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥5,800	-442.2%	¥579M ($3.7M)
2024-12-20	SELL	negotiated	都丸由美子 Yumiko Tomaru	activist	330.5K	¥5,800	-442.2%	¥579M ($3.7M)
2024-12-20	SELL	negotiated	細江由紀子 Yukiko Hosoe	activist	282.5K	¥5,800	-442.2%	¥866M ($5.6M)
2024-12-11	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥5,000	+529.0%	¥3.3B ($21.1M)
2024-12-11	BUY	negotiated	有限会社光研 Kouken Co., Ltd.	activist	583.5K	¥5,000	+529.0%	¥2.9B ($18.8M)
2024-12-11	BUY	negotiated	有限会社高志 Takashi Co., Ltd.	activist	654.4K	¥5,000	+529.0%	¥3.3B ($21.1M)

Showing the 50 most recent of 73 filings.

Frequently asked questions

Who has been buying SEIKOH GIKEN Co., Ltd. stock?: 11 distinct investors have filed 8 disclosed large-shareholding filings in SEIKOH GIKEN Co., Ltd. (6834), most recently on 2025-10-09. 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 SEIKOH GIKEN Co., Ltd. have?: SEIKOH GIKEN Co., Ltd. has 8 buy-side and 16 sell-side disclosures on record, covering ¥5.1B ($32.6M) in total reported value, spanning 2021-12-02 to 2025-10-09.
Where does StockDrifts get SEIKOH GIKEN 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 SEIKOH GIKEN Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.