Who has been buying Open Up Group Inc. stock?

13 distinct investors have filed 39 disclosed large-shareholding filings in Open Up Group Inc. (2154), most recently on 2026-03-06. 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 Open Up Group Inc. have?

Open Up Group Inc. has 39 buy-side and 31 sell-side disclosures on record, covering ¥50.2B ($323.7M) in total reported value, spanning 2021-04-06 to 2026-03-06.

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.

Open Up Group Inc. 2154

Company

株式会社夢真ビーネックスグループOpen Up Group Inc.

Investors

Buys

Total Value

¥50.2B ($323.7M)

Avg Return

+9.56%

Last Filing

2026-03-06

Open Up Group Inc. (2154) has 39 disclosed large-shareholding filings and 31 disclosed disposals on record, filed by 13 distinct investors. Together those filings cover ¥50.2B ($323.7M) in reported transaction value. The earliest filing StockDrifts holds for Open Up Group Inc. is dated 2021-04-06; the most recent is 2026-03-06. Across these filings the average return since disclosure is +9.56%, 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
2026-08-21	SELL	Market Buy	M&Gインベストメント・マネジメント・リミテッド、M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investment Management Limited	passive	8.1M	¥2,039	+0.1%	¥1.9B ($11.9M)
2026-08-21	SELL	Market Buy	M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investments (Singapore	passive	8.1M	¥2,039	+0.1%	¥1.9B ($11.9M)
2026-03-06	BUY	Market Buy	M&Gインベストメント・マネジメント・リミテッド、M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investment Management Limited	passive	9.0M	¥1,848	+10.2%	¥2.2B ($14.2M)
2026-03-06	BUY	Market Buy	M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investments (Singapore	passive	9.0M	¥1,848	-	¥16.6B ($107.2M)
2025-09-19	SELL	Market Buy	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	other	2.3M	¥1,765	-15.3%	¥16M ($105K)
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	1.9M	¥1,765	+15.3%	¥65M ($418K)
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	1.1M	¥1,765	+15.3%	¥421M ($2.7M)
2025-09-04	SELL	Market Buy	株式会社アミューズキャピタル Amuse Capital Inc.	strategic	6.2M	¥1,873	-8.7%	¥17M ($111K)
2025-09-04	BUY	Market Buy	株式会社アミューズキャピタルインベストメント Amuse Capital Investment Inc.	strategic	2.4M	¥1,873	-	¥4.5B ($28.8M)
2025-09-04	SELL	Market Buy	中山隼雄 Hayao Nakayama	strategic	8.4M	¥1,873	-8.7%	¥34M ($222K)
2025-08-20	SELL	unknown	有限会社志 kokoro	strategic	4.2M	¥1,935	-5.2%	¥3.5B ($22.5M)
2024-09-06	BUY	Market Buy	M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investments (Singapore	passive	7.9M	¥2,011	-	¥15.9B ($102.3M)
2024-09-06	BUY	Market Buy	M&Gインベストメント・マネジメント・リミテッド、M&Gインベストメンツ(シンガポール)ピーティーイー・リミテッドPte. Ltd.) M&G Investment Management Limited	passive	7.9M	¥2,011	+1.2%	¥1.3B ($8.7M)
2024-04-03	BUY	unknown	株式会社レソラ Resola Co., Ltd.	strategic	1.1M	¥2,000	+1.8%	¥2.1B ($13.6M)
2024-04-03	BUY	unknown	有限会社志 Kokoro Co.,Ltd.	strategic	6.0M	¥2,000	-	-
2024-04-03	SELL	unknown	佐藤淑子 Yoshiko Sato	strategic	2.7M	¥2,000	-1.8%	¥2.1B ($13.7M)
2024-04-03	BUY	unknown	佐藤大央 Daio Sato	activist	3.0M	¥2,000	-	-
2024-04-03	BUY	unknown	株式会社愛央 Aio Co., Ltd.	strategic	2.8M	¥2,000	-	-
2024-02-21	SELL	unknown	有限会社志 Kokoro Co.,Ltd.	strategic	6.0M	¥2,186	+6.9%	¥80M ($518K)
2024-02-21	SELL	unknown	有限会社志 Kokoro Co.,Ltd.	strategic	6.0M	¥2,186	+6.9%	¥80M ($518K)
2024-02-21	SELL	unknown	佐藤淑子 Yoshiko Sato	strategic	3.8M	¥2,186	+6.9%	¥2.2B ($14.5M)
2024-02-21	SELL	unknown	佐藤大央 Daio Sato	activist	3.0M	¥2,186	+6.9%	¥522M ($3.4M)
2024-02-21	BUY	unknown	株式会社愛央 Aio Co., Ltd.	strategic	2.8M	¥2,186	-6.9%	¥1.2B ($7.6M)
2024-02-21	SELL	unknown	佐藤淑子 Yoshiko Sato	strategic	3.8M	¥2,186	+6.9%	¥2.2B ($14.5M)
2024-02-21	SELL	unknown	佐藤大央 Daio Sato	activist	3.0M	¥2,186	+6.9%	¥542M ($3.5M)
2024-02-21	BUY	unknown	株式会社愛央 Aio Co., Ltd.	strategic	2.8M	¥2,186	-6.9%	¥1.2B ($7.6M)
2024-02-19	SELL	unknown	株式会社アミューズキャピタル Amuse Capital Inc.	strategic	6.2M	¥2,141	+4.9%	¥2.2B ($14.2M)
2024-02-19	SELL	unknown	中山隼雄 Hayao Nakayama	strategic	8.4M	¥2,141	+4.9%	¥59M ($380K)
2023-11-08	BUY	Market Buy	M&Gインベストメント・マネジメント・リミテッド(M&G Investment Management Limited) M&G Investment Management Limited	passive	7.2M	¥1,942	+4.8%	¥2.0B ($13.2M)
2023-08-07	BUY	Market Buy	M&Gインベストメント・マネジメント・リミテッド(M&G Investment Management Limited) M&G Investment Management Limited	passive	6.1M	¥2,138	-4.8%	¥2.0B ($12.6M)
2023-06-22	BUY	Market Buy	M&Gインベストメント・マネジメント・リミテッド(M&G Investment Management Limited) M&G Investment Management Limited	passive	5.2M	¥2,181	-6.7%	¥11.4B ($73.5M)
2023-02-21	BUY	unknown	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	other	2.3M	¥1,906	-	-
2023-02-21	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	¥1,906	-6.8%	¥785M ($5.1M)
2023-02-21	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	864.7K	¥1,906	-6.8%	¥349M ($2.3M)
2023-01-19	BUY	unknown	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	other	2.3M	¥1,861	-	-
2023-01-19	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	2.2M	¥1,861	-	-
2023-01-19	BUY	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	1.0M	¥1,861	+9.4%	¥17M ($110K)
2022-12-06	SELL	unknown	三井住友信託銀行株式会社 Sumitomo Mitsui Trust Bank,Limited	other	2.3M	¥1,820	-11.9%	¥17M ($107K)
2022-12-06	BUY	unknown	三井住友トラスト・アセットマネジメント株式会社 Sumitomo Mitsui Trust Asset Management Co.,Ltd.	other	2.2M	¥1,820	+11.9%	¥266M ($1.7M)
2022-12-06	SELL	unknown	日興アセットマネジメント株式会社 Nikko Asset Management Co.,Ltd.	other	1.0M	¥1,820	-11.9%	¥66M ($429K)
2022-11-15	BUY	unknown	株式会社アミューズキャピタル Amuse Capital Inc.	strategic	7.2M	¥1,899	+7.2%	¥13.4B ($86.5M)
2022-11-15	BUY	unknown	中山隼雄 Hayao Nakayama	strategic	8.4M	¥1,899	+7.2%	¥15.6B ($100.5M)
2022-11-14	SELL	unknown	有限会社志 Kokoro Co.,Ltd.	strategic	6.0M	¥1,895	-7.4%	¥35M ($223K)
2022-11-14	SELL	unknown	有限会社志 Kokoro Co.,Ltd.	strategic	6.0M	¥1,895	-7.4%	¥35M ($223K)
2022-11-14	BUY	unknown	佐藤大央 Daio Sato	activist	3.2M	¥1,895	+7.4%	¥52M ($335K)
2022-11-14	SELL	unknown	佐藤淑子 Yoshiko Sato	strategic	4.8M	¥1,895	-7.4%	¥1.9B ($12.4M)
2022-11-14	BUY	unknown	佐藤大央 Daio Sato	activist	3.2M	¥1,895	+7.4%	¥52M ($335K)
2022-11-14	SELL	unknown	株式会社愛央 Aio Co., Ltd.	strategic	2.3M	¥1,895	-7.4%	¥17M ($112K)
2022-11-14	SELL	unknown	佐藤淑子 Yoshiko Sato	strategic	4.8M	¥1,895	-7.4%	¥1.9B ($12.4M)
2022-11-14	SELL	unknown	株式会社愛央 Aio Co., Ltd.	strategic	2.3M	¥1,895	-7.4%	¥17M ($112K)

Showing the 50 most recent of 90 filings.

Frequently asked questions

Who has been buying Open Up Group Inc. stock?: 13 distinct investors have filed 39 disclosed large-shareholding filings in Open Up Group Inc. (2154), most recently on 2026-03-06. 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 Open Up Group Inc. have?: Open Up Group Inc. has 39 buy-side and 31 sell-side disclosures on record, covering ¥50.2B ($323.7M) in total reported value, spanning 2021-04-06 to 2026-03-06.
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.