Who has been buying Simplex Holdings, Inc. stock?

15 distinct investors have filed 26 disclosed large-shareholding filings in Simplex Holdings, Inc. (4373), most recently on 2025-11-26. 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 Simplex Holdings, Inc. have?

Simplex Holdings, Inc. has 26 buy-side and 32 sell-side disclosures on record, covering ¥29.5B ($190.2M) in total reported value, spanning 2021-09-22 to 2025-11-26.

Where does StockDrifts get Simplex 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.

Simplex Holdings, Inc. 4373

Company

シンプレクス・ホールディングス株式会社Simplex Holdings, Inc.

Investors

Buys

Total Value

¥29.5B ($190.2M)

Avg Return

+54.97%

Last Filing

2025-11-26

Simplex Holdings, Inc. (4373) has 26 disclosed large-shareholding filings and 32 disclosed disposals on record, filed by 15 distinct investors. Together those filings cover ¥29.5B ($190.2M) in reported transaction value. The earliest filing StockDrifts holds for Simplex Holdings, Inc. is dated 2021-09-22; the most recent is 2025-11-26. 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 +54.97%, 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
2025-11-26	SELL	unknown	五十嵐充 Mitsuru Igarashi	strategic	4.7M	¥1,102.5	+14.0%	¥670M ($4.3M)
2025-06-19	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	1.5M	¥955	+0.7%	¥258M ($1.7M)
2025-06-19	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	1.1M	¥955	+0.7%	¥594M ($3.8M)
2025-03-21	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	1.8M	¥730.5	-29.8%	¥171M ($1.1M)
2025-03-21	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	1.8M	¥730.5	-29.8%	¥321M ($2.1M)
2025-02-05	BUY	negotiated	TK&Company株式会社 TK&Company Co., Ltd.	activist	1.5M	¥722.75	+31.2%	¥1.1B ($6.8M)
2025-02-05	BUY	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	1.5M	¥722.75	+31.2%	¥1.1B ($6.8M)
2025-02-05	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.1M	¥722.75	-31.2%	¥512M ($3.3M)
2024-12-20	SELL	negotiated	TK&Company株式会社 TK&Company Co., Ltd.	activist	1.5M	¥626.5	-51.3%	¥4M ($24K)
2024-12-20	SELL	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	1.5M	¥626.5	-51.3%	¥4M ($24K)
2024-12-20	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥626.5	-51.3%	¥51M ($331K)
2024-04-25	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥659	-43.9%	¥8M ($49K)
2024-04-25	BUY	negotiated	TK&Company株式会社 TK&Company Co., Ltd.	activist	1.5M	¥659	+43.9%	¥959M ($6.2M)
2024-04-25	BUY	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	1.5M	¥659	+43.9%	¥959M ($6.2M)
2024-03-22	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	2.0M	¥725.75	+30.6%	¥589M ($3.8M)
2024-03-22	SELL	unknown	三井住友トラスト・アセットマネジメント株式会社 Sumitomo Mitsui Trust Asset Management Co.,Ltd.	other	2.2M	¥725.75	-30.6%	¥38M ($244K)
2024-03-08	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥696.5	-36.1%	¥44M ($287K)
2024-03-08	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥696.5	-36.1%	¥44M ($287K)
2024-03-08	BUY	negotiated	TK&Company株式会社 TK&Company Co., Ltd.	activist	1.5M	¥696.5	+36.1%	¥1.0B ($6.5M)
2024-03-08	SELL	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	1.5M	¥696.5	-36.1%	¥1.0B ($6.7M)
2024-03-08	BUY	negotiated	TK&Company株式会社 TK&Company Co., Ltd.	activist	1.5M	¥696.5	+36.1%	¥1.0B ($6.5M)
2024-03-08	SELL	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	1.5M	¥696.5	-36.1%	¥1.0B ($6.7M)
2023-12-28	SELL	negotiated	YK&Company株式会社 YK&Company Co., Ltd.	activist	2.9M	¥680	-39.4%	¥4M ($25K)
2023-12-28	SELL	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥680	-39.4%	¥16M ($101K)
2023-12-06	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	1.1M	¥631.5	+50.1%	¥393M ($2.5M)
2023-12-06	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	2.2M	¥631.5	-50.1%	¥116M ($751K)
2023-11-13	SELL	unknown	五十嵐充 Mitsuru Igarashi	strategic	5.2M	¥604.75	-56.8%	¥721M ($4.7M)
2023-09-05	BUY	negotiated	合同会社H・Y・T・R LLC H・Y・T・R	activist	2.9M	¥734.75	+29.0%	¥2.1B ($13.8M)
2023-09-05	BUY	negotiated	合同会社H・Y・T・R LLC H・Y・T・R	activist	2.9M	¥734.75	+29.0%	¥2.1B ($13.8M)
2023-09-05	BUY	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥734.75	+29.0%	¥5.7B ($36.6M)
2023-09-05	BUY	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥734.75	+29.0%	¥5.7B ($37.1M)
2023-08-18	BUY	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥650	+45.9%	¥5.0B ($32.3M)
2023-08-18	BUY	negotiated	合同会社H・Y・T・R LLC H・Y・T・R	activist	2.9M	¥650	+45.9%	¥1.9B ($12.2M)
2023-08-18	BUY	negotiated	合同会社H・Y・T・R LLC H・Y・T・R	activist	2.9M	¥650	+45.9%	¥1.9B ($12.2M)
2023-08-18	BUY	negotiated	金子英樹 Hideki Kaneko	activist	7.8M	¥650	+45.9%	¥5.0B ($32.3M)
2023-05-12	SELL	negotiated	金子英樹 Hideki Kaneko	activist	10.7M	¥602	-57.5%	¥429M ($2.8M)
2023-04-10	SELL	Market Buy	KARITA & Company Micronesia Inc.	passive	917.5K	¥607.5	-56.0%	¥92M ($595K)
2023-04-10	SELL	Market Buy	株式会社刈田・アンド・カンパニー Katta & Company Co., Ltd.	passive	1.3M	¥607.5	-56.0%	¥130M ($838K)
2023-04-10	BUY	Market Buy	K&Cホールディングス株式会社 K&C Holdings Inc.	passive	374.6K	¥607.5	+56.0%	¥96M ($617K)
2023-02-06	BUY	Market Buy	SBIホールディングス株式会社 SBI Holdings, Inc.	passive	3.0M	¥606.25	+56.4%	¥1.8B ($11.9M)
2023-01-26	SELL	unknown	五十嵐充 Mitsuru Igarashi	strategic	6.3M	¥558.5	-69.7%	¥857M ($5.5M)
2023-01-13	BUY	unknown	田中健一 Kenichi Tanaka	strategic	2.4M	¥527.75	+79.6%	¥303M ($2.0M)
2023-01-13	SELL	unknown	田中健一 Kenichi Tanaka	strategic	2.4M	¥527.75	-79.6%	¥303M ($2.0M)
2022-11-29	SELL	unknown	福井康人 Yasuhito Fukui	strategic	2.6M	¥576.75	-64.4%	¥174M ($1.1M)
2022-11-02	SELL	negotiated	金子英樹 Hideki Kaneko	activist	11.2M	¥580.75	-63.2%	¥764M ($4.9M)
2022-08-04	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	504.1K	¥550.5	+72.2%	¥278M ($1.8M)
2022-08-04	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	2.3M	¥550.5	+72.2%	¥1.3B ($8.2M)
2022-02-22	SELL	unknown	フィデリティ投信株式会社 FIL Investments (Japan) Limited	other	2.4M	¥382.25	-148.0%	¥230M ($1.5M)
2022-01-21	BUY	Market Buy	農林中金全共連アセットマネジメント株式会社 Norinchukin Zenkyoren Asset Management Co., Ltd.	passive	101.7K	¥605.5	+56.6%	¥3M ($20K)
2022-01-21	SELL	Market Buy	農林中央金庫 The Norinchukin Bank	strategic	2.4M	¥605.5	-56.6%	¥18M ($117K)

Showing the 50 most recent of 74 filings.

Frequently asked questions

Who has been buying Simplex Holdings, Inc. stock?: 15 distinct investors have filed 26 disclosed large-shareholding filings in Simplex Holdings, Inc. (4373), most recently on 2025-11-26. 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 Simplex Holdings, Inc. have?: Simplex Holdings, Inc. has 26 buy-side and 32 sell-side disclosures on record, covering ¥29.5B ($190.2M) in total reported value, spanning 2021-09-22 to 2025-11-26.
Where does StockDrifts get Simplex 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 Simplex Holdings, Inc.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.