Who has been buying Kumagai Gumi Co.,Ltd. stock?

12 distinct investors have filed 26 disclosed large-shareholding filings in Kumagai Gumi Co.,Ltd. (1861), most recently on 2026-05-01. 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 Kumagai Gumi Co.,Ltd. have?

Kumagai Gumi Co.,Ltd. has 26 buy-side and 17 sell-side disclosures on record, covering ¥18.7B ($120.4M) in total reported value, spanning 2021-05-12 to 2026-05-01.

Where does StockDrifts get Kumagai Gumi 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.

Kumagai Gumi Co.,Ltd. 1861

Company

株式会社熊谷組Kumagai Gumi Co.,Ltd.

Investors

Buys

Total Value

¥18.7B ($120.4M)

Avg Return

+74.90%

Last Filing

2026-05-01

Kumagai Gumi Co.,Ltd. (1861) has 26 disclosed large-shareholding filings and 17 disclosed disposals on record, filed by 12 distinct investors. Together those filings cover ¥18.7B ($120.4M) in reported transaction value. The earliest filing StockDrifts holds for Kumagai Gumi Co.,Ltd. is dated 2021-05-12; the most recent is 2026-05-01. 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 +74.90%, 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	BUY	Market Buy	アセットマネジメントOneインターナショナル Asset Management One International Ltd.	other	257.3K	¥1,388	-6.1%	¥24M ($155K)
2026-08-07	SELL	unknown	みずほ証券株式会社	other	34.6K	¥1,388	+6.1%	¥577M ($3.7M)
2026-08-07	SELL	unknown	アセットマネジメントOne株式会社	other	9.6M	¥1,388	+6.1%	¥1.9B ($12.4M)
2026-07-01	SELL	unknown	熊谷組取引先持株会理事長新妻尚祐 Kumagai Gumi Business Partner's Shareholding Association	strategic	0	¥1,420	-0.8%	¥12.5B ($80.7M)
2026-07-01	BUY	unknown	熊谷組取引先持株会理事長片山篤 Kumagai Gumi Business Partner Shareholding Association	strategic	9.7M	¥1,420	+0.8%	¥13.8B ($89.0M)
2026-05-22	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	14.2M	¥1,424	-3.0%	¥2.6B ($17.0M)
2026-05-01	SELL	unknown	オアシスマネジメントカンパニーリミテッド(Oasis Management Company Ltd.) Oasis Management Company Ltd.	activist	2.6M	¥1,496	+4.4%	¥22.6B ($145.7M)
2026-03-23	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	12.4M	¥1,578	-4.2%	¥5.1B ($32.8M)
2026-03-05	SELL	unknown	アモーヴァ・アセットマネジメント株式会社	other	11.8M	¥1,750	+13.6%	¥17.8B ($114.9M)
2026-03-05	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	3.7M	¥1,750	+13.6%	¥5.6B ($36.0M)
2026-02-20	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	9.2M	¥1,980	-23.6%	¥18.1B ($117.0M)
2026-02-06	BUY	Market Buy	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	11.7M	¥1,915	-21.0%	¥5.7B ($36.6M)
2026-01-26	SELL	negotiated	住友林業株式会社 Sumitomo Forestry Co.,Ltd.	strategic	27.5M	¥1,761	+14.1%	¥12.6B ($81.4M)
2025-09-19	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 Sumitomo Mitsui Trust Asset Management Co.,Ltd.	other	1.1M	¥1,222.5	-23.7%	¥5M ($34K)
2025-09-19	BUY	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	3.2M	¥1,222.5	+23.7%	¥42M ($273K)
2025-09-04	BUY	Market Buy	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	3.1M	¥1,211.25	+24.8%	¥84M ($541K)
2025-09-04	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	1.2M	¥1,211.25	+24.8%	¥16M ($101K)
2025-05-09	BUY	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	2.2M	¥1,088.75	+38.9%	¥2.4B ($15.3M)
2025-05-08	BUY	Market Buy	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	3.1M	¥1,072.5	+41.0%	¥32M ($210K)
2025-05-08	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	1.1M	¥1,072.5	+41.0%	¥88M ($569K)
2025-03-21	BUY	Market Buy	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	3.0M	¥1,031.25	+46.6%	¥451M ($2.9M)
2025-03-21	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 Sumitomo Mitsui Trust Asset Management Co.,Ltd.	other	1.1M	¥1,031.25	-46.6%	¥187M ($1.2M)
2024-03-18	BUY	Market Buy	オアシスマネジメントカンパニーリミテッド(Oasis Management Company Ltd.) Oasis Management Company Ltd.	activist	4.4M	¥1,011.25	+49.5%	¥1.4B ($8.9M)
2023-11-07	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	2.6M	¥901.25	-67.8%	¥376M ($2.4M)
2023-11-07	SELL	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	1.3M	¥901.25	-67.8%	¥51M ($332K)
2023-07-12	BUY	unknown	熊谷組取引先持株会理事長新妻尚祐 Kumagai Gumi Business Partner's Shareholding Association	strategic	2.2M	¥773.75	+95.4%	¥1.7B ($11.2M)
2023-06-05	SELL	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	1.1M	¥771.25	-96.0%	¥14M ($87K)
2023-06-05	SELL	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	69.7K	¥771.25	-96.0%	¥108M ($699K)
2023-06-05	SELL	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	200.3K	¥771.25	-96.0%	¥504M ($3.3M)
2023-05-29	BUY	unknown	オアシスマネジメントカンパニーリミテッド(Oasis Management Company Ltd.) Oasis Management Company Ltd.	activist	3.1M	¥727.25	+107.9%	¥2.3B ($14.6M)
2023-05-23	SELL	Market Buy	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	3.1M	¥734.25	-105.9%	¥345M ($2.2M)
2023-05-23	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	1.3M	¥734.25	+105.9%	¥164M ($1.1M)
2023-05-18	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	1.1M	¥733	+106.3%	¥830M ($5.4M)
2023-05-18	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	212.1K	¥733	+106.3%	¥155M ($1.0M)
2023-05-18	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	858.1K	¥733	+106.3%	¥629M ($4.1M)
2023-03-20	SELL	Market Buy	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	1.2M	¥672.75	-124.8%	¥3M ($20K)
2023-03-20	SELL	Market Buy	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	21.4K	¥672.75	-124.8%	¥406M ($2.6M)
2023-03-20	BUY	Market Buy	野村證券株式会社 Nomura Securities Co.,Ltd.	other	963.8K	¥672.75	+124.8%	¥165M ($1.1M)
2023-03-03	SELL	Market Buy	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	1.2M	¥706.5	-114.0%	¥16M ($103K)
2023-03-03	SELL	Market Buy	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	626.6K	¥706.5	-114.0%	¥170M ($1.1M)
2023-03-03	BUY	Market Buy	野村證券株式会社 Nomura Securities Co.,Ltd.	other	715.6K	¥706.5	+114.0%	¥321M ($2.1M)
2022-12-06	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	1.2M	¥637.75	+137.1%	¥778M ($5.0M)
2022-12-06	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	868.7K	¥637.75	+137.1%	¥554M ($3.6M)
2022-12-06	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	261.2K	¥637.75	+137.1%	¥167M ($1.1M)
2021-11-09	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	3.8M	¥693.5	+118.0%	¥338M ($2.2M)
2021-11-09	SELL	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	1.2M	¥693.5	-118.0%	¥104M ($670K)
2021-09-07	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	1.2M	¥698.75	+116.4%	¥798M ($5.1M)
2021-09-07	BUY	Market Buy	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	591.4K	¥698.75	+116.4%	¥413M ($2.7M)
2021-05-12	BUY	Market Buy	株式会社三井住友銀行 Sumitomo Mitsui Banking Corporation	other	591.4K	¥768.75	+96.7%	¥455M ($2.9M)
2021-05-12	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	1.8M	¥768.75	+96.7%	¥1.4B ($9.1M)

Frequently asked questions

Who has been buying Kumagai Gumi Co.,Ltd. stock?: 12 distinct investors have filed 26 disclosed large-shareholding filings in Kumagai Gumi Co.,Ltd. (1861), most recently on 2026-05-01. 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 Kumagai Gumi Co.,Ltd. have?: Kumagai Gumi Co.,Ltd. has 26 buy-side and 17 sell-side disclosures on record, covering ¥18.7B ($120.4M) in total reported value, spanning 2021-05-12 to 2026-05-01.
Where does StockDrifts get Kumagai Gumi 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 Kumagai Gumi Co.,Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.