Who has been buying Seibu Holdings Inc. stock?

19 distinct investors have filed 17 disclosed large-shareholding filings in Seibu Holdings Inc. (9024), 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 Seibu Holdings Inc. have?

Seibu Holdings Inc. has 17 buy-side and 18 sell-side disclosures on record, covering ¥28.4B ($183.0M) in total reported value, spanning 2021-05-11 to 2026-03-23.

Where does StockDrifts get Seibu Holdings Inc. 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.

Seibu Holdings Inc. 9024

Company

株式会社西武ホールディングスSeibu Holdings Inc.

Investors

Buys

Total Value

¥28.4B ($183.0M)

Avg Return

+211.69%

Last Filing

2026-03-23

Seibu Holdings Inc. (9024) has 17 disclosed large-shareholding filings and 18 disclosed disposals on record, filed by 19 distinct investors. Together those filings cover ¥28.4B ($183.0M) in reported transaction value. The earliest filing StockDrifts holds for Seibu Holdings Inc. is dated 2021-05-11; the most recent is 2026-03-23. 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 +211.69%, 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
2026-07-09	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	42.5M	¥3,473	-3.8%	¥11.2B ($71.9M)
2026-07-03	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	39.3M	¥3,402	+4.7%	¥15.1B ($97.3M)
2026-06-25	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	34.9M	¥3,018	+18.0%	¥10.5B ($67.9M)
2026-06-22	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	31.4M	¥3,036	+19.2%	¥11.6B ($74.9M)
2026-06-12	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	27.6M	¥2,994	+16.0%	¥9.6B ($62.0M)
2026-06-05	BUY	block_purchase	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	24.4M	¥2,656	+28.1%	¥8.5B ($55.0M)
2026-05-25	BUY	Market Buy	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	21.2M	¥2,942.5	+1.5%	¥10.5B ($67.9M)
2026-03-23	SELL	unknown	アセットマネジメントOne株式会社	other	4.4M	¥4,143	+2.5%	¥17.8B ($114.9M)
2026-03-23	BUY	unknown	みずほ信託銀行株式会社	strategic	4.4M	¥4,143	-2.5%	¥17.9B ($115.4M)
2026-03-23	BUY	unknown	みずほ証券株式会社	other	2.7M	¥4,143	+2.5%	¥11.1B ($71.4M)
2026-03-23	SELL	unknown	株式会社みずほ銀行	strategic	5.7M	¥4,143	+2.5%	¥23.0B ($148.7M)
2024-11-14	BUY	Market Buy	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	18.6M	¥3,602	+12.2%	¥8.6B ($55.6M)
2024-10-04	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	4.9M	¥3,302	-22.4%	¥3.4B ($22.1M)
2024-10-04	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	9.0M	¥3,302	-22.4%	¥8.8B ($56.5M)
2024-05-14	BUY	acquisition	3Dインベストメント・パートナーズ・プライベート・リミティッド(3D Investment Partners Pte. Ltd.) 3D Investment Partners Pte. Ltd.	activist	16.2M	¥2,141	+88.7%	¥34.7B ($223.9M)
2024-05-08	SELL	negotiated	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	5.9M	¥2,364	-70.9%	¥1.1B ($7.4M)
2024-05-08	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	11.6M	¥2,364	-70.9%	¥3.5B ($22.7M)
2024-05-08	SELL	negotiated	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	300.0K	¥2,364	-70.9%	¥3.1B ($20.2M)
2022-03-04	BUY	negotiated	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	6.4M	¥1,193	+238.6%	¥386M ($2.5M)
2022-03-04	BUY	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	13.1M	¥1,193	+238.6%	¥3.5B ($22.7M)
2022-03-04	BUY	negotiated	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	1.6M	¥1,193	+238.6%	¥1.9B ($12.3M)
2021-06-04	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	214.5K	¥1,415	-185.5%	¥641M ($4.1M)
2021-06-04	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	2.3M	¥1,415	-185.5%	¥2.9B ($18.9M)
2021-06-04	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	2.4M	¥1,415	-185.5%	¥2.3B ($14.8M)
2021-06-04	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	391.7K	¥1,415	-185.5%	¥1.2B ($8.0M)
2021-06-04	BUY	Market Buy	ブラックロック(ルクセンブルグ)エス・エーS.A.) BlackRock (Luxembourg	passive	421.8K	¥1,415	+185.5%	¥597M ($3.9M)
2021-06-04	SELL	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	379.8K	¥1,415	-185.5%	¥92M ($591K)
2021-06-04	SELL	Market Buy	ブラックロック(ネザーランド)BVBV) BlackRock (Netherlands	passive	313.2K	¥1,415	-185.5%	¥320M ($2.1M)
2021-06-04	SELL	Market Buy	ブラックロック・インベストメント・マネジメント (オーストラリア)リミテッドLimited) BlackRock Investment Management (Australia	passive	1.3M	¥1,415	-185.5%	¥92M ($591K)
2021-06-04	SELL	Market Buy	ブラックロック・インベストメント・マネジメント・エルエルシー BlackRock Investment Management LLC	passive	917.6K	¥1,415	-185.5%	¥320M ($2.1M)
2021-06-04	SELL	Market Buy	ブラックロック・アドバイザーズ・エルエルシー(BlackRock Advisers BlackRock Advisers, LLC	passive	230.4K	¥1,415	-185.5%	¥137M ($886K)
2021-06-04	SELL	Market Buy	ブラックロック・ジャパン株式会社 BlackRock Japan Co., Ltd.	passive	2.8M	¥1,415	-185.5%	¥46M ($295K)
2021-05-11	BUY	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	672.7K	¥1,148	+251.9%	¥772M ($5.0M)
2021-05-11	BUY	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	4.3M	¥1,148	+251.9%	¥5.0B ($32.0M)
2021-05-11	BUY	Market Buy	ブラックロック・ファンド・アドバイザーズ BlackRock Fund Advisors	passive	4.1M	¥1,148	+251.9%	¥4.7B ($30.0M)
2021-05-11	BUY	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	1.3M	¥1,148	+251.9%	¥1.4B ($9.3M)
2021-05-11	BUY	Market Buy	ブラックロック(ルクセンブルグ)エス・エーS.A.) BlackRock (Luxembourg	passive	432.5K	¥1,148	+251.9%	¥497M ($3.2M)
2021-05-11	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	444.0K	¥1,148	+251.9%	¥510M ($3.3M)
2021-05-11	BUY	Market Buy	ブラックロック(ネザーランド)BVBV) BlackRock (Netherlands	passive	550.2K	¥1,148	+251.9%	¥632M ($4.1M)
2021-05-11	BUY	Market Buy	ブラックロック・インベストメント・マネジメント (オーストラリア)リミテッドLimited) BlackRock Investment Management (Australia	passive	1.3M	¥1,148	+251.9%	¥1.5B ($9.9M)
2021-05-11	BUY	Market Buy	ブラックロック・インベストメント・マネジメント・エルエルシー BlackRock Investment Management LLC	passive	1.1M	¥1,148	+251.9%	¥1.3B ($8.3M)
2021-05-11	BUY	Market Buy	ブラックロック・アドバイザーズ・エルエルシー(BlackRock Advisers BlackRock Advisers, LLC	passive	330.6K	¥1,148	+251.9%	¥379M ($2.4M)
2021-05-11	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	6.1M	¥1,148	+251.9%	¥37M ($240K)
2021-05-11	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	10.2M	¥1,148	-251.9%	¥854M ($5.5M)
2021-05-11	BUY	unknown	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	strategic	1.6M	¥1,148	+251.9%	¥1.8B ($11.9M)
2021-05-11	BUY	Market Buy	ブラックロック・ジャパン株式会社 BlackRock Japan Co., Ltd.	passive	2.8M	¥1,148	+251.9%	¥3.2B ($20.8M)

Frequently asked questions

Who has been buying Seibu Holdings Inc. stock?: 19 distinct investors have filed 17 disclosed large-shareholding filings in Seibu Holdings Inc. (9024), 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 Seibu Holdings Inc. have?: Seibu Holdings Inc. has 17 buy-side and 18 sell-side disclosures on record, covering ¥28.4B ($183.0M) in total reported value, spanning 2021-05-11 to 2026-03-23.
Where does StockDrifts get Seibu Holdings Inc. 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 Seibu Holdings Inc.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.