Who has been buying Riso Kagaku Corporation stock?

6 distinct investors have filed 17 disclosed large-shareholding filings in Riso Kagaku Corporation (6413), most recently on 2026-01-08. 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 Riso Kagaku Corporation have?

Riso Kagaku Corporation has 17 buy-side and 2 sell-side disclosures on record, covering ¥2.7B ($17.6M) in total reported value, spanning 2023-04-17 to 2026-01-08.

Where does StockDrifts get Riso Kagaku 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.

Riso Kagaku Corporation 6413

Company

理想科学工業株式会社Riso Kagaku Corporation

Investors

Buys

Total Value

¥2.7B ($17.6M)

Avg Return

-23.46%

Last Filing

2026-01-08

Riso Kagaku Corporation (6413) has 17 disclosed large-shareholding filings and 2 disclosed disposals on record, filed by 6 distinct investors. Together those filings cover ¥2.7B ($17.6M) in reported transaction value. The earliest filing StockDrifts holds for Riso Kagaku Corporation is dated 2023-04-17; the most recent is 2026-01-08. 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 -23.46%, 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
2026-01-08	BUY	unknown	有限会社理想社	strategic	9.9M	¥1,249	+9.5%	¥11.2B ($72.1M)
2026-01-08	BUY	unknown	あかつき興産株式会社	strategic	3.9M	¥1,249	+9.5%	¥4.4B ($28.6M)
2026-01-08	SELL	unknown	羽山明	other	2.0M	¥1,249	+9.5%	¥2.2B ($14.2M)
2024-07-19	BUY	unknown	有限会社理想社 Risosha Co., Ltd.	strategic	4.9M	¥1,535	-26.4%	¥763M ($4.9M)
2024-07-19	BUY	unknown	あかつき興産株式会社 Akatsuki Kosan Co., Ltd.	strategic	2.0M	¥1,535	-26.4%	¥298M ($1.9M)
2024-07-19	BUY	Market Buy	有限会社理想社 Risosha Co., Ltd.	strategic	4.9M	¥1,535	-26.4%	¥763M ($4.9M)
2024-07-19	BUY	Market Buy	あかつき興産株式会社 Akatsuki Kosan Co., Ltd.	strategic	2.0M	¥1,535	-26.4%	¥298M ($1.9M)
2024-07-19	BUY	Market Buy	羽山明 AKIRA HAYAMA	other	1.0M	¥1,535	-26.4%	¥83M ($535K)
2024-07-19	BUY	unknown	羽山明 AKIRA HAYAMA	other	1.0M	¥1,535	-26.4%	¥83M ($535K)
2024-04-05	BUY	unknown	株式会社昭和 Showa Co., Ltd.	other	788.2K	¥1,525	-25.9%	¥1.2B ($7.8M)
2024-04-05	BUY	unknown	羽山智恵 Chie Hayama	other	97.2K	¥1,525	-25.9%	¥148M ($956K)
2024-04-05	BUY	unknown	羽山尚 Takashi Hayama	other	1.1M	¥1,525	-25.9%	¥1.7B ($11.3M)
2024-04-02	BUY	unknown	羽山智恵 Chie Hayama	other	97.2K	¥1,532.5	-26.3%	¥149M ($961K)
2024-04-02	BUY	unknown	羽山尚 Takashi Hayama	other	1.1M	¥1,532.5	-26.3%	¥1.8B ($11.3M)
2024-04-02	BUY	unknown	株式会社昭和 Showa Co., Ltd.	other	788.2K	¥1,532.5	-26.3%	¥1.2B ($7.8M)
2024-04-02	BUY	unknown	株式会社昭和 Showa Co., Ltd.	other	788.2K	¥1,532.5	-26.3%	¥1.2B ($7.8M)
2024-04-02	BUY	unknown	羽山尚 Takashi Hayama	other	1.1M	¥1,532.5	-26.3%	¥1.8B ($11.3M)
2024-04-02	BUY	unknown	羽山智恵 Chie Hayama	other	97.2K	¥1,532.5	-26.3%	¥149M ($961K)
2023-04-17	BUY	unknown	有限会社理想社 Risosha Co., Ltd.	strategic	4.9M	¥1,160.5	-2.6%	¥896M ($5.8M)
2023-04-17	BUY	unknown	あかつき興産株式会社 Akatsuki Kosan Co., Ltd.	strategic	2.0M	¥1,160.5	-2.6%	¥381M ($2.5M)
2023-04-17	SELL	unknown	羽山明 AKIRA HAYAMA	other	1.1M	¥1,160.5	+2.6%	¥139M ($898K)

Frequently asked questions

Who has been buying Riso Kagaku Corporation stock?: 6 distinct investors have filed 17 disclosed large-shareholding filings in Riso Kagaku Corporation (6413), most recently on 2026-01-08. 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 Riso Kagaku Corporation have?: Riso Kagaku Corporation has 17 buy-side and 2 sell-side disclosures on record, covering ¥2.7B ($17.6M) in total reported value, spanning 2023-04-17 to 2026-01-08.
Where does StockDrifts get Riso Kagaku 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 Riso Kagaku Corporation. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.