Who has been buying Tosoh Corporation stock?

19 distinct investors have filed 14 disclosed large-shareholding filings in Tosoh Corporation (4042), most recently on 2025-10-02. 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 Tosoh Corporation have?

Tosoh Corporation has 14 buy-side and 22 sell-side disclosures on record, covering ¥30.4B ($196.2M) in total reported value, spanning 2021-07-06 to 2025-10-02.

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.

Tosoh Corporation 4042

Company

東ソー株式会社Tosoh Corporation

Investors

Buys

Total Value

¥30.4B ($196.2M)

Avg Return

+21.20%

Last Filing

2025-10-02

Tosoh Corporation (4042) has 14 disclosed large-shareholding filings and 22 disclosed disposals on record, filed by 19 distinct investors. Together those filings cover ¥30.4B ($196.2M) in reported transaction value. The earliest filing StockDrifts holds for Tosoh Corporation is dated 2021-07-06; the most recent is 2025-10-02. Across these filings the average return since disclosure is +21.20%, 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
2025-10-02	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	19.4M	¥2,168.5	-22.5%	¥7.6B ($49.1M)
2025-09-19	BUY	Market Buy	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	6.7M	¥2,296.5	-	-
2025-09-19	BUY	Market Buy	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	8.5M	¥2,296.5	+15.7%	¥2.1B ($13.5M)
2025-09-19	SELL	Market Buy	アモーヴァ・アセットマネジメント株式会社 Amova Asset Management Co., Ltd.	other	6.6M	¥2,296.5	-15.7%	¥448M ($2.9M)
2025-05-07	BUY	Market Buy	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	18.1M	¥2,009.5	+32.2%	¥3.7B ($24.0M)
2025-05-07	SELL	Market Buy	野村證券株式会社 Nomura Securities Co.,Ltd.	other	541.3K	¥2,009.5	-32.2%	¥241.7B ($1.6B)
2025-05-07	BUY	Market Buy	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	1.2M	¥2,009.5	+32.2%	¥3.3B ($21.1M)
2025-03-24	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	22.9M	¥2,173	-22.3%	¥1.5B ($9.6M)
2024-10-31	BUY	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	23.6M	¥1,910	+39.1%	¥6.8B ($43.7M)
2024-10-16	BUY	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	20.1M	¥1,913	+38.9%	¥7.0B ($44.9M)
2024-06-06	BUY	negotiated	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	6.7M	¥2,041	-	-
2024-06-06	SELL	negotiated	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	7.5M	¥2,041	-30.2%	¥66M ($428K)
2024-06-06	BUY	negotiated	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	6.8M	¥2,041	+30.2%	¥398M ($2.6M)
2024-06-05	BUY	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	16.5M	¥1,993.5	+33.3%	¥32.8B ($211.7M)
2024-05-20	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	16.3M	¥1,975	+34.5%	¥193M ($1.2M)
2024-05-20	SELL	unknown	ノムラセキュリテーズインターナショナル NOMURA SECURITIES INTERNATIONAL,Inc.	unknown	0	¥1,975	-34.5%	¥963M ($6.2M)
2024-05-20	SELL	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	-491.9K	¥1,975	-23.4%	¥10.2B ($65.9M)
2024-05-20	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	1.8M	¥1,975	-	¥3.5B ($22.4M)
2024-03-25	BUY	unknown	ノムラセキュリテーズインターナショナル NOMURA SECURITIES INTERNATIONAL,Inc.	other	480.0K	¥2,103.5	-	¥1.0B ($6.5M)
2024-03-25	SELL	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	304.9K	¥2,103.5	-26.3%	¥615M ($4.0M)
2024-03-25	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	4.7M	¥2,103.5	+26.3%	¥9.9B ($64.0M)
2024-03-25	SELL	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	16.2M	¥2,103.5	-26.3%	¥2.0B ($12.8M)
2024-03-07	SELL	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	7.0M	¥2,037.5	-30.4%	¥2.1B ($13.2M)
2024-03-07	BUY	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	646.2K	¥2,037.5	-	¥1.3B ($8.5M)
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	9.3M	¥2,037.5	-30.4%	¥6.3B ($40.6M)
2024-03-05	BUY	Market Buy	ブラックロック・ライフ・リミテッド BlackRock Life Limited	passive	44.7K	¥2,024.5	+31.2%	¥5.4B ($34.8M)
2024-03-05	SELL	Market Buy	ブラックロック・ジャパン株式会社 BlackRock Japan Co., Ltd.	passive	5.6M	¥2,024.5	-31.2%	¥395M ($2.5M)
2024-03-05	BUY	Market Buy	ブラックロック・ファンド・マネジャーズ・リミテッド BlackRock Fund Managers Limited	passive	623.9K	¥2,024.5	-	¥1.3B ($8.1M)
2024-03-05	SELL	Market Buy	ブラックロック・アセット・マネジメント・アイルランド・リミテッド BlackRock Asset Management Ireland Limited	passive	470.5K	¥2,024.5	-31.2%	¥1.6B ($10.2M)
2024-03-05	SELL	Market Buy	ブラックロック・ファンド・アドバイザーズ BlackRock Fund Advisors	passive	2.9M	¥2,024.5	-31.2%	¥2.0B ($12.7M)
2024-03-05	SELL	Market Buy	ブラックロック・インスティテューショナル・トラスト・カンパニー、エヌ.エイ.(BlackRock Institutional Trust Company BlackRock Institutional Trust Company, N.A.	passive	1.7M	¥2,024.5	-31.2%	¥5.5B ($35.7M)
2024-03-05	SELL	Market Buy	ブラックロック・インベストメント・マネジメント(ユーケー)リミテッドLimited) BlackRock Investment Management (UK	passive	244.7K	¥2,024.5	-31.2%	¥921M ($5.9M)
2023-12-06	SELL	negotiated	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	7.6M	¥1,902	-39.7%	¥4.3B ($27.9M)
2023-12-06	BUY	negotiated	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	6.6M	¥1,902	+39.7%	¥1.7B ($10.8M)
2023-12-06	SELL	negotiated	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	6.7M	¥1,902	-39.7%	¥1.5B ($10.0M)
2022-09-21	SELL	unknown	アライアンス・バーンスタイン・エル・ピー(AllianceBernstein L.P.) AllianceBernstein L.P.	other	13.3M	¥1,700	-56.3%	¥5.7B ($36.7M)
2022-04-06	SELL	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	17.1M	¥1,710	-55.4%	¥500M ($3.2M)
2022-04-06	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	584.9K	¥1,710	-	¥1.0B ($6.5M)
2022-04-06	SELL	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	-18.1K	¥1,710	-42.5%	¥6.5B ($42.0M)
2021-07-20	SELL	unknown	アライアンス・バーンスタイン・エル・ピー(AllianceBernstein L.P.) AllianceBernstein L.P.	other	16.7M	¥1,832	-45.0%	¥298M ($1.9M)
2021-07-06	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	68.5K	¥2,010	+32.2%	¥11.6B ($74.6M)
2021-07-06	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	3.8M	¥2,010	+32.2%	¥7.6B ($48.9M)
2021-07-06	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	17.4M	¥2,010	+32.2%	¥719M ($4.6M)

Frequently asked questions

Who has been buying Tosoh Corporation stock?: 19 distinct investors have filed 14 disclosed large-shareholding filings in Tosoh Corporation (4042), most recently on 2025-10-02. 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 Tosoh Corporation have?: Tosoh Corporation has 14 buy-side and 22 sell-side disclosures on record, covering ¥30.4B ($196.2M) in total reported value, spanning 2021-07-06 to 2025-10-02.
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.