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

10 distinct investors have filed 18 disclosed large-shareholding filings in Riken Keiki Co., Ltd. (7734), most recently on 2026-03-23. 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 Keiki Co., Ltd. have?

Riken Keiki Co., Ltd. has 18 buy-side and 17 sell-side disclosures on record, covering ¥15.0B ($96.6M) in total reported value, spanning 2021-12-07 to 2026-03-23.

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 Keiki Co., Ltd. 7734

Company

理研計器株式会社Riken Keiki Co., Ltd.

Investors

Buys

Total Value

¥15.0B ($96.6M)

Avg Return

+25.86%

Last Filing

2026-03-23

Riken Keiki Co., Ltd. (7734) has 18 disclosed large-shareholding filings and 17 disclosed disposals on record, filed by 10 distinct investors. Together those filings cover ¥15.0B ($96.6M) in reported transaction value. The earliest filing StockDrifts holds for Riken Keiki Co., Ltd. is dated 2021-12-07; the most recent is 2026-03-23. Across these filings the average return since disclosure is +25.86%, 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
2026-05-18	SELL	Market Buy	フォレスト・マナー・エヌ・ヴイ(Forest Manor N.V.) Forest Manor N.V.	passive	2.1M	¥3,750	+6.4%	¥1.8B ($11.7M)
2026-03-23	SELL	unknown	SMBC日興証券株式会社	other	13.9K	¥3,030	-15.8%	¥186M ($1.2M)
2026-03-23	BUY	unknown	三井住友DSアセットマネジメント株式会社	passive	2.4M	¥3,030	+15.8%	¥1.5B ($9.9M)
2026-03-23	SELL	unknown	株式会社三井住友銀行	other	1.3M	¥3,030	-15.8%	¥1.0B ($6.8M)
2025-06-20	SELL	unknown	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	2.2M	¥2,933	-19.7%	¥1.7B ($11.2M)
2025-04-07	BUY	Market Buy	キャピタル・リサーチ・アンド・マネージメント・カンパニー(Capital Research and Management Company) Capital Research and Management Company	passive	3.2M	¥2,186	+60.6%	¥1.8B ($11.5M)
2024-12-06	BUY	Market Buy	キャピタル・リサーチ・アンド・マネージメント・カンパニー(Capital Research and Management Company) Capital Research and Management Company	passive	2.4M	¥3,700	-5.1%	¥8.8B ($57.1M)
2024-12-06	BUY	Market Buy	キャピタル・リサーチ・アンド・マネージメント・カンパニー(Capital Research and Management Company) Capital Research and Management Company	passive	2.4M	¥3,700	-	¥8.8B ($57.1M)
2024-11-22	SELL	Market Buy	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.8M	¥3,715	+5.5%	¥387M ($2.5M)
2024-11-22	BUY	Market Buy	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	275.2K	¥3,715	-	¥1.0B ($6.6M)
2024-11-22	SELL	Market Buy	みずほ信託銀行株式会社 Mizuho Trust & Banking Co., Ltd.	strategic	240.0K	¥3,715	+5.5%	¥299M ($1.9M)
2024-11-22	SELL	Market Buy	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	796.3K	¥3,715	+5.5%	¥105M ($681K)
2024-09-24	SELL	unknown	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	2.8M	¥4,115	+14.7%	¥2.0B ($12.9M)
2024-04-05	SELL	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.9M	¥3,635	+3.4%	¥1.3B ($8.7M)
2024-04-05	BUY	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	26.8K	¥3,635	-3.4%	¥9.8B ($63.3M)
2024-04-05	SELL	unknown	みずほ信託銀行株式会社 Mizuho Trust & Banking Co., Ltd.	strategic	323.6K	¥3,635	+3.4%	¥1.3B ($8.7M)
2024-04-05	BUY	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	825.6K	¥3,635	-3.4%	¥482M ($3.1M)
2024-03-25	BUY	Market Buy	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	38.6K	¥3,730	-5.9%	¥18M ($114K)
2024-03-25	BUY	Market Buy	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	837.1K	¥3,730	-	-
2024-03-25	BUY	Market Buy	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	941.5K	¥3,730	-5.9%	¥962M ($6.2M)
2024-02-07	SELL	unknown	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	1.6M	¥3,965	+11.5%	¥2.4B ($15.3M)
2023-04-21	BUY	Market Buy	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	684.6K	¥2,595	+35.3%	¥694M ($4.5M)
2023-04-21	BUY	Market Buy	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	837.1K	¥2,595	-	-
2023-04-21	BUY	Market Buy	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	33.9K	¥2,595	+35.3%	¥6M ($40K)
2023-02-22	SELL	Market Buy	シンフォニー・フィナンシャル・パートナーズ(シンガポール)ピーティーイー・リミテッド(Symphony Financial Partners (Singapore) Pte. Ltd.) Symphony Financial Partners (Singapore) Pte. Ltd.	passive	1.1M	¥2,580	-36.0%	¥818M ($5.3M)
2022-11-22	SELL	Market Buy	シンフォニー・フィナンシャル・パートナーズ(シンガポール)ピーティーイー・リミテッド(Symphony Financial Partners (Singapore) Pte. Ltd.) Symphony Financial Partners (Singapore) Pte. Ltd.	passive	1.4M	¥2,575	-36.3%	¥1.2B ($7.6M)
2022-11-22	BUY	unknown	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	29.7K	¥2,575	+36.3%	¥76M ($493K)
2022-11-22	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	416.1K	¥2,575	+36.3%	¥1.1B ($6.9M)
2022-11-22	BUY	unknown	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	837.1K	¥2,575	+36.3%	¥2.2B ($13.9M)
2022-10-21	SELL	Market Buy	シンフォニー・フィナンシャル・パートナーズ(シンガポール)ピーティーイー・リミテッド(Symphony Financial Partners (Singapore) Pte. Ltd.) Symphony Financial Partners (Singapore) Pte. Ltd.	passive	1.9M	¥1,977.5	-77.5%	¥566M ($3.7M)
2022-10-07	SELL	Market Buy	シンフォニー・フィナンシャル・パートナーズ(シンガポール)ピーティーイー・リミテッド(Symphony Financial Partners (Singapore) Pte. Ltd.) Symphony Financial Partners (Singapore) Pte. Ltd.	passive	2.2M	¥2,035	-72.5%	¥515M ($3.3M)
2022-09-27	SELL	Market Buy	シンフォニー・フィナンシャル・パートナーズ(シンガポール)ピーティーイー・リミテッド(Symphony Financial Partners (Singapore) Pte. Ltd.) Symphony Financial Partners (Singapore) Pte. Ltd.	activist	2.4M	¥2,000	-75.5%	¥710M ($4.6M)
2022-09-26	BUY	Market Buy	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	2.2M	¥2,015	+74.2%	¥620M ($4.0M)
2022-09-07	BUY	Market Buy	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	1.9M	¥2,145	+63.6%	¥675M ($4.4M)
2022-04-22	BUY	Market Buy	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	1.6M	¥2,142.5	+63.8%	¥796M ($5.1M)
2022-03-07	BUY	unknown	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	837.1K	¥2,332.5	-	-
2022-03-07	SELL	unknown	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	70.3K	¥2,332.5	-50.5%	¥938M ($6.1M)
2022-02-07	BUY	unknown	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	1.2M	¥2,625	+33.7%	¥3.2B ($20.7M)
2022-01-11	BUY	unknown	SMBC日興証券株式会社 SMBC Nikko Securities Inc.	other	472.4K	¥2,655	+32.2%	¥1.3B ($8.1M)
2022-01-11	BUY	unknown	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	837.1K	¥2,655	+32.2%	¥2.2B ($14.3M)
2021-12-07	BUY	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	1.1M	¥2,695	-	-
2021-12-07	BUY	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	70.1K	¥2,695	-	¥189M ($1.2M)
2021-12-07	BUY	unknown	みずほ信託銀行株式会社 Mizuho Trust & Banking Co., Ltd.	strategic	345.0K	¥2,695	-	-
2021-12-07	SELL	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	344.7K	¥2,695	-30.2%	¥281M ($1.8M)

Frequently asked questions

Who has been buying Riken Keiki Co., Ltd. stock?: 10 distinct investors have filed 18 disclosed large-shareholding filings in Riken Keiki Co., Ltd. (7734), most recently on 2026-03-23. 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 Keiki Co., Ltd. have?: Riken Keiki Co., Ltd. has 18 buy-side and 17 sell-side disclosures on record, covering ¥15.0B ($96.6M) in total reported value, spanning 2021-12-07 to 2026-03-23.
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.

More on this data

Every trade listed above comes from an official regulatory disclosure. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.