Who has been buying KOSÉ Corporation stock?

17 distinct investors have filed 16 disclosed large-shareholding filings in KOSÉ Corporation (4922), most recently on 2026-04-06. 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 KOSÉ Corporation have?

KOSÉ Corporation has 16 buy-side and 11 sell-side disclosures on record, covering ¥276.9B ($1.8B) in total reported value, spanning 2021-04-06 to 2026-04-06.

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.

KOSÉ Corporation 4922

Company

株式会社コーセーホールディングスKOSÉ Corporation

Investors

Buys

Total Value

¥276.9B ($1.8B)

Avg Return

-36.39%

Last Filing

2026-04-06

KOSÉ Corporation (4922) has 16 disclosed large-shareholding filings and 11 disclosed disposals on record, filed by 17 distinct investors. Together those filings cover ¥276.9B ($1.8B) in reported transaction value. The earliest filing StockDrifts holds for KOSÉ Corporation is dated 2021-04-06; the most recent is 2026-04-06. Across these filings the average return since disclosure is -36.39%, 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
2026-07-22	SELL	unknown	三井住友トラスト・アセットマネジメント株式会社	other	1.1M	¥5,472	-3.2%	¥66M ($428K)
2026-07-22	SELL	unknown	アモーヴァ・アセットマネジメント株式会社	other	3.3M	¥5,472	-3.2%	¥66M ($428K)
2026-07-06	BUY	Market Buy	MFSインベストメント・マネジメント株式会社	passive	79.7K	¥5,417	-	-
2026-07-06	SELL	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	3.7M	¥5,417	-4.3%	¥4.6B ($29.4M)
2026-07-06	BUY	unknown	三井住友トラスト・アセットマネジメント株式会社	other	1.1M	¥5,417	-	-
2026-07-06	BUY	Market Buy	アモーヴァ・アセットマネジメント株式会社	other	3.3M	¥5,417	+4.3%	¥5.3B ($33.9M)
2026-04-06	SELL	Market Buy	三井住友トラスト・アセットマネジメント株式会社	other	1.1M	¥6,136	+7.9%	¥223M ($1.4M)
2026-04-06	BUY	Market Buy	アモーヴァ・アセットマネジメント株式会社	other	2.3M	¥6,136	-7.9%	¥2.0B ($12.7M)
2026-03-19	BUY	Market Buy	MFSインベストメント・マネジメント株式会社	passive	79.7K	¥5,881	-3.9%	¥107M ($690K)
2026-03-19	SELL	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	4.5M	¥5,881	+3.9%	¥3.6B ($23.2M)
2026-02-05	BUY	unknown	三井住友トラスト・アセットマネジメント株式会社 Sumitomo Mitsui Trust Asset Management Co.,Ltd.	other	3.1M	¥5,836	-3.2%	¥18.3B ($118.3M)
2025-12-12	SELL	unknown	小林正典	activist	653.7K	¥5,411	-4.4%	¥361M ($2.3M)
2025-12-12	BUY	unknown	一般社団法人MYMラボラトリーズ	strategic	5.5M	¥5,411	-	-
2025-12-12	BUY	unknown	MYMアセット合同会社	other	550.0K	¥5,411	-	-
2025-12-12	BUY	unknown	MYMパートナーズ株式会社	other	150.0K	¥5,411	+4.4%	¥164M ($1.1M)
2025-12-12	BUY	unknown	MYMドネーション株式会社	other	40.2K	¥5,411	-	¥218M ($1.4M)
2024-11-21	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	5.1M	¥6,776	-16.6%	¥4.4B ($28.3M)
2024-11-21	SELL	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	59.1K	¥6,776	+16.6%	¥164M ($1.1M)
2024-08-08	SELL	unknown	小林一俊 Kazutoshi Kobayashi	activist	723.8K	¥8,858	+36.2%	¥51.6B ($332.8M)
2024-08-08	SELL	unknown	小林正典 Masanori Kobayashi	activist	723.0K	¥8,858	+36.2%	¥50.0B ($322.4M)
2024-08-08	BUY	unknown	AMTアセット合同会社 AMT Asset LLC	other	550.0K	¥8,858	-	-
2024-08-08	BUY	unknown	THKパートナーズ株式会社 THK Partners Co., Ltd.	other	120.0K	¥8,858	-	¥1.1B ($6.9M)
2024-08-08	BUY	unknown	一般社団法人MYMラボラトリーズ MYM Laboratories Association	strategic	5.5M	¥8,858	-	¥48.6B ($313.8M)
2024-08-08	BUY	unknown	一般社団法人ウッド Wood Association	strategic	5.6M	¥8,858	-	¥49.6B ($319.7M)
2024-08-08	BUY	unknown	一般社団法人コーセーマネジメント KOSE Management Association	strategic	5.7M	¥8,858	-	¥50.3B ($324.6M)
2024-08-08	BUY	unknown	THKアセット合同会社 THK Asset LLC	unknown	550.0K	¥8,858	-	-
2024-08-08	SELL	unknown	小林孝雄 Takao Kobayashi	activist	723.4K	¥8,858	+36.2%	¥51.1B ($329.7M)
2024-08-08	BUY	unknown	AMTパートナーズ株式会社 AMT Partners Co., Ltd.	other	120.0K	¥8,858	-	¥1.1B ($6.9M)
2024-08-08	BUY	unknown	MYMアセット合同会社 MYM Asset LLC	other	550.0K	¥8,858	-	-
2024-08-08	BUY	unknown	MYMパートナーズ株式会社 MYM Partners Co., Ltd.	other	120.0K	¥8,858	-	¥1.1B ($6.9M)
2024-05-08	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	4.5M	¥8,368	-32.5%	¥7.5B ($48.1M)
2024-05-08	BUY	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	84.3K	¥8,368	-32.5%	¥152M ($981K)
2024-01-22	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	3.6M	¥9,460	-40.3%	¥5.8B ($37.7M)
2024-01-22	SELL	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	68.8K	¥9,460	+40.3%	¥229M ($1.5M)
2023-06-22	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	3.0M	¥14,115	-60.0%	¥41.6B ($268.6M)
2023-06-22	BUY	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	88.8K	¥14,115	-	-
2023-05-10	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	3.8M	¥15,400	-63.3%	¥57.3B ($369.8M)
2023-05-10	SELL	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	89.5K	¥15,400	+63.3%	¥373M ($2.4M)
2023-03-22	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	4.6M	¥15,040	-62.4%	¥69.1B ($445.9M)
2023-03-22	SELL	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	113.5K	¥15,040	+62.4%	¥638M ($4.1M)
2022-02-04	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	5.2M	¥11,400	-50.5%	¥9.1B ($58.8M)
2022-02-04	BUY	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	154.9K	¥11,400	-50.5%	¥207M ($1.3M)
2021-10-20	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	4.4M	¥14,040	-59.8%	¥11.7B ($75.2M)
2021-10-20	BUY	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	140.0K	¥14,040	-59.8%	¥340M ($2.2M)
2021-04-06	BUY	Market Buy	マサチューセッツ・ファイナンシャル・サービセズ・カンパニー Massachusetts Financial Services Company	passive	3.6M	¥15,790	-64.2%	¥56.1B ($361.7M)
2021-04-06	SELL	Market Buy	MFSインベストメント・マネジメント株式会社 MFS Investment Management K.K.	passive	118.0K	¥15,790	+64.2%	¥191M ($1.2M)

Frequently asked questions

Who has been buying KOSÉ Corporation stock?: 17 distinct investors have filed 16 disclosed large-shareholding filings in KOSÉ Corporation (4922), most recently on 2026-04-06. 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 KOSÉ Corporation have?: KOSÉ Corporation has 16 buy-side and 11 sell-side disclosures on record, covering ¥276.9B ($1.8B) in total reported value, spanning 2021-04-06 to 2026-04-06.
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.