Who has been buying Seika Corporation stock?

12 distinct investors have filed 21 disclosed large-shareholding filings in Seika Corporation (8061), most recently on 2025-08-07. 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 Seika Corporation have?

Seika Corporation has 21 buy-side and 6 sell-side disclosures on record, covering ¥1.3B ($8.6M) in total reported value, spanning 2021-08-12 to 2025-08-07.

Where does StockDrifts get Seika Corporation 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.

Seika Corporation 8061

Company

西華産業株式会社Seika Corporation

Investors

Buys

Total Value

¥1.3B ($8.6M)

Avg Return

+231.41%

Last Filing

2025-08-07

Seika Corporation (8061) has 21 disclosed large-shareholding filings and 6 disclosed disposals on record, filed by 12 distinct investors. Together those filings cover ¥1.3B ($8.6M) in reported transaction value. The earliest filing StockDrifts holds for Seika Corporation is dated 2021-08-12; the most recent is 2025-08-07. 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 +231.41%, 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
2025-08-07	BUY	Market Buy	さくら損害保険株式会社 Sakura General Insurance Co., Ltd.	passive	38.5K	¥2,010	+40.5%	¥15M ($96K)
2025-08-07	BUY	Market Buy	株式会社エヌオーアイ NIO Co., Ltd.	passive	65.3K	¥2,010	+40.5%	¥131M ($847K)
2025-08-07	BUY	Market Buy	株式会社エスアイエル SIL Co., Ltd.	passive	121.0K	¥2,010	+40.5%	¥99M ($639K)
2025-08-07	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	121.2K	¥2,010	+40.5%	¥244M ($1.6M)
2025-08-07	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	789.9K	¥2,010	+40.5%	¥1.6B ($10.2M)
2025-08-07	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥2,010	+40.5%	¥1.8B ($11.6M)
2025-05-09	BUY	Market Buy	さくら損害保険株式会社 Sakura General Insurance Co., Ltd.	passive	30.2K	¥1,496.67	+88.6%	¥7M ($48K)
2025-05-09	BUY	Market Buy	株式会社エスアイエル SIL Co., Ltd.	passive	70.9K	¥1,496.67	+88.6%	¥106M ($685K)
2025-05-09	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	121.2K	¥1,496.67	+88.6%	¥77M ($500K)
2025-05-09	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	789.9K	¥1,496.67	+88.6%	¥1.2B ($7.6M)
2025-05-09	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥1,496.67	+88.6%	¥1.3B ($8.6M)
2025-02-21	SELL	Market Buy	さくら損害保険株式会社 Sakura General Insurance Co., Ltd.	passive	26.4K	¥1,456.67	-93.8%	¥1.9B ($12.5M)
2025-02-21	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	69.2K	¥1,456.67	+93.8%	¥101M ($650K)
2025-02-21	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	789.9K	¥1,456.67	+93.8%	¥63M ($405K)
2025-02-21	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥1,456.67	+93.8%	¥1.3B ($8.4M)
2024-12-16	BUY	negotiated	三菱UFJモルガン・スタンレー証券株式会社 Mitsubishi UFJ Morgan Stanley Securities Co., Ltd.	other	90.3K	¥1,578.33	+78.9%	¥142M ($919K)
2024-12-16	BUY	negotiated	三菱UFJアセットマネジメント株式会社 Mitsubishi UFJ Financial Group Inc.	passive	62.7K	¥1,578.33	+78.9%	¥18M ($113K)
2024-12-16	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	201.0K	¥1,578.33	+78.9%	¥33M ($213K)
2024-12-16	SELL	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	82.7K	¥1,578.33	-78.9%	¥502M ($3.2M)
2024-12-09	BUY	Market Buy	さくら損害保険株式会社 Sakura General Insurance Co., Ltd.	passive	13.4K	¥1,510	+87.0%	¥20M ($131K)
2024-12-09	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	747.2K	¥1,510	+87.0%	¥186M ($1.2M)
2024-12-09	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥1,510	+87.0%	¥1.3B ($8.7M)
2024-07-29	BUY	Market Buy	三菱UFJモルガン・スタンレー証券株式会社 Mitsubishi UFJ Morgan Stanley Securities Co., Ltd.	other	2.3K	¥1,405	+100.9%	¥306M ($2.0M)
2024-07-29	BUY	Market Buy	三菱UFJアセットマネジメント株式会社 Mitsubishi UFJ Financial Group Inc.	passive	52.0K	¥1,405	+100.9%	¥23M ($145K)
2024-07-29	SELL	Market Buy	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	179.7K	¥1,405	-100.9%	¥74M ($480K)
2024-07-29	BUY	Market Buy	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	400.0K	¥1,405	+100.9%	¥23M ($145K)
2023-11-15	BUY	Market Buy	さくら損害保険株式会社 Sakura General Insurance Co., Ltd.	passive	13.4K	¥821.67	+243.6%	¥11M ($71K)
2023-11-15	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	623.0K	¥821.67	+243.6%	¥91M ($588K)
2023-11-15	SELL	unknown	三菱重工業株式会社 Mitsubishi Heavy Industries, Ltd.	other	534.0K	¥821.67	-243.6%	¥112M ($725K)
2023-11-15	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥821.67	+243.6%	¥733M ($4.7M)
2023-08-30	SELL	unknown	三菱重工業株式会社 Mitsubishi Heavy Industries, Ltd.	other	670.8K	¥697.33	-304.8%	¥86M ($554K)
2023-04-07	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥686.67	+311.1%	¥612M ($3.9M)
2023-04-07	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	512.4K	¥686.67	+311.1%	¥85M ($551K)
2022-11-08	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	387.6K	¥538	+424.7%	¥67M ($432K)
2022-11-08	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥538	+424.7%	¥480M ($3.1M)
2022-09-13	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	264.0K	¥542	+420.9%	¥68M ($439K)
2022-09-13	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥542	+420.9%	¥483M ($3.1M)
2022-04-07	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	138.1K	¥513	+450.3%	¥63M ($408K)
2022-04-07	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥513	+450.3%	¥18M ($118K)
2021-12-17	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	16.0K	¥543.33	+419.6%	¥9M ($56K)
2021-12-17	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	891.6K	¥543.33	+419.6%	¥65M ($418K)
2021-12-16	BUY	Market Buy	三菱パワー株式会社 Mitsubishi Power, Ltd.	other	826.3K	¥550	+413.3%	¥56M ($359K)
2021-12-16	BUY	unknown	三菱重工業株式会社 Mitsubishi Heavy Industries, Ltd.	other	826.3K	¥550	+413.3%	¥454M ($2.9M)
2021-12-16	SELL	unknown	三菱パワー株式会社 Mitsubishi Power, Ltd.	unknown	0	¥550	-413.3%	¥454M ($2.9M)
2021-08-12	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	771.9K	¥550	+413.3%	¥71M ($455K)

Frequently asked questions

Who has been buying Seika Corporation stock?: 12 distinct investors have filed 21 disclosed large-shareholding filings in Seika Corporation (8061), most recently on 2025-08-07. 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 Seika Corporation have?: Seika Corporation has 21 buy-side and 6 sell-side disclosures on record, covering ¥1.3B ($8.6M) in total reported value, spanning 2021-08-12 to 2025-08-07.
Where does StockDrifts get Seika Corporation 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 Seika Corporation. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.