Who has been buying Riken Vitamin Co., Ltd. stock?

9 distinct investors have filed 19 disclosed large-shareholding filings in Riken Vitamin Co., Ltd. (4526), most recently on 2025-05-01. 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 Riken Vitamin Co., Ltd. have?

Riken Vitamin Co., Ltd. has 19 buy-side and 10 sell-side disclosures on record, covering ¥10.8B ($69.7M) in total reported value, spanning 2022-05-20 to 2025-05-01.

Where does StockDrifts get Riken Vitamin 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.

Riken Vitamin Co., Ltd. 4526

Company

理研ビタミン株式会社Riken Vitamin Co., Ltd.

Investors

Buys

Total Value

¥10.8B ($69.7M)

Avg Return

+34.54%

Last Filing

2025-05-01

Riken Vitamin Co., Ltd. (4526) has 19 disclosed large-shareholding filings and 10 disclosed disposals on record, filed by 9 distinct investors. Together those filings cover ¥10.8B ($69.7M) in reported transaction value. The earliest filing StockDrifts holds for Riken Vitamin Co., Ltd. is dated 2022-05-20; the most recent is 2025-05-01. 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 +34.54%, 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
2026-08-07	SELL	unknown	理研ビタミン取引先持株会理事長小林光夫 MITSUO KOBAYASHI	unknown	0	¥3,155	-4.0%	¥10.3B ($66.2M)
2026-08-07	BUY	unknown	理研ビタミン取引先持株会理事長保坂晴彦 HARUHIKO HOSAKA	strategic	3.4M	¥3,155	+4.0%	¥10.7B ($69.1M)
2025-05-01	BUY	Market Buy	理研ビタミン取引先持株会理事長小林光夫 MITSUO KOBAYASHI	strategic	3.3M	¥2,563	+11.6%	¥787M ($5.1M)
2025-03-07	BUY	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	345.5K	¥2,410	+18.7%	¥171M ($1.1M)
2025-03-07	SELL	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	27.5K	¥2,410	-18.7%	¥122M ($786K)
2025-03-07	SELL	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.0M	¥2,410	-18.7%	¥837M ($5.4M)
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	38.9K	¥2,441	+17.2%	¥95M ($613K)
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	109.4K	¥2,441	+17.2%	¥267M ($1.7M)
2024-12-16	SELL	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	903.3K	¥2,441	-17.2%	¥658M ($4.2M)
2024-12-16	SELL	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	442.8K	¥2,441	-17.2%	¥362M ($2.3M)
2024-07-29	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	590.4K	¥2,810	+1.8%	¥1.7B ($10.7M)
2024-07-29	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	16.2K	¥2,810	+1.8%	¥4.6B ($29.8M)
2024-07-29	SELL	negotiated	三菱UFJアセットマネジメント株式会社 Mitsubishi UFJ Financial Group Inc.	passive	106.6K	¥2,810	-1.8%	¥9M ($61K)
2024-07-29	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	1.2M	¥2,810	+1.8%	¥597M ($3.8M)
2024-03-25	BUY	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	78.8K	¥2,578	+10.9%	¥203M ($1.3M)
2024-03-25	BUY	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.4M	¥2,578	+10.9%	¥3.6B ($23.1M)
2024-03-25	BUY	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	276.1K	¥2,578	+10.9%	¥712M ($4.6M)
2024-03-07	SELL	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	283.0K	¥2,495	-14.6%	¥269M ($1.7M)
2024-03-07	BUY	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.4M	¥2,495	+14.6%	¥3.4B ($22.0M)
2024-02-05	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	41.1K	¥2,346	+21.9%	¥96M ($622K)
2024-02-05	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	961.0K	¥2,346	+21.9%	¥2.3B ($14.5M)
2024-02-05	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	111.1K	¥2,346	+21.9%	¥261M ($1.7M)
2024-02-05	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	590.4K	¥2,346	+21.9%	¥1.4B ($8.9M)
2023-12-18	SELL	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	590.4K	¥2,181	-31.1%	¥323M ($2.1M)
2023-12-18	SELL	negotiated	三菱UFJアセットマネジメント株式会社 Mitsubishi UFJ Financial Group Inc.	passive	110.2K	¥2,181	-31.1%	¥15M ($95K)
2023-12-18	SELL	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	965.0K	¥2,181	-31.1%	¥522M ($3.4M)
2023-07-05	SELL	unknown	理研ビタミン取引先持株会理事長石田一 HAJIME ISHIDA	unknown	0	¥2,071	-38.1%	¥6.3B ($40.7M)
2023-07-05	BUY	unknown	理研ビタミン取引先持株会理事長小林光夫 MITSUO KOBAYASHI	strategic	3.2M	¥2,071	+38.1%	¥6.7B ($43.3M)
2022-05-31	BUY	Market Buy	理研ビタミン取引先持株会理事長石田一 HAJIME ISHIDA	strategic	3.0M	¥1,613	+77.3%	¥968M ($6.2M)
2022-05-30	BUY	Market Buy	三菱UFJ国際投信株式会社 Mitsubishi UFJ Financial Group Inc.	passive	119.1K	¥1,647	+73.7%	¥56M ($358K)
2022-05-30	BUY	Market Buy	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	1.2M	¥1,647	+73.7%	¥328M ($2.1M)
2022-05-30	BUY	Market Buy	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	738.0K	¥1,647	+73.7%	¥172M ($1.1M)
2022-05-20	BUY	Market Buy	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	391.9K	¥1,630	+75.5%	¥192M ($1.2M)
2022-05-20	BUY	Market Buy	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.7M	¥1,630	+75.5%	¥483M ($3.1M)

Frequently asked questions

Who has been buying Riken Vitamin Co., Ltd. stock?: 9 distinct investors have filed 19 disclosed large-shareholding filings in Riken Vitamin Co., Ltd. (4526), most recently on 2025-05-01. 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 Riken Vitamin Co., Ltd. have?: Riken Vitamin Co., Ltd. has 19 buy-side and 10 sell-side disclosures on record, covering ¥10.8B ($69.7M) in total reported value, spanning 2022-05-20 to 2025-05-01.
Where does StockDrifts get Riken Vitamin 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 Riken Vitamin Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.