Who has been buying Tokyo Steel Manufacturing Co., Ltd. stock?

7 distinct investors have filed 14 disclosed large-shareholding filings in Tokyo Steel Manufacturing Co., Ltd. (5423), most recently on 2026-05-13. 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 Tokyo Steel Manufacturing Co., Ltd. have?

Tokyo Steel Manufacturing Co., Ltd. has 14 buy-side and 4 sell-side disclosures on record, covering ¥55.8B ($359.9M) in total reported value, spanning 2022-06-21 to 2026-05-13.

Where does StockDrifts get Tokyo Steel Manufacturing 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.

Tokyo Steel Manufacturing Co., Ltd. 5423

Company

東京製鐵株式会社Tokyo Steel Manufacturing Co., Ltd.

Investors

Buys

Total Value

¥55.8B ($359.9M)

Avg Return

+19.74%

Last Filing

2026-05-13

Tokyo Steel Manufacturing Co., Ltd. (5423) has 14 disclosed large-shareholding filings and 4 disclosed disposals on record, filed by 7 distinct investors. Together those filings cover ¥55.8B ($359.9M) in reported transaction value. The earliest filing StockDrifts holds for Tokyo Steel Manufacturing Co., Ltd. is dated 2022-06-21; the most recent is 2026-05-13. 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 +19.74%, 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
2026-05-13	BUY	unknown	合同会社MYJ	strategic	4.8M	¥1,701	-0.2%	¥8.2B ($52.7M)
2026-05-13	BUY	unknown	合同会社TOS	strategic	25.0M	¥1,701	-0.2%	¥42.6B ($274.6M)
2026-05-13	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.	other	9.5M	¥1,701	-0.2%	¥37M ($242K)
2026-05-11	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	9.5M	¥1,656	+2.5%	¥4.3B ($28.0M)
2026-04-02	BUY	acquisition	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	6.9M	¥1,627	+4.1%	¥11.2B ($72.3M)
2025-10-28	BUY	unknown	合同会社MYJ LLC MYJ	strategic	4.8M	¥1,356	+31.3%	¥1.9B ($12.1M)
2025-10-28	BUY	Market Buy	合同会社TOS TOS LLC	strategic	25.0M	¥1,356	+31.3%	¥16.2B ($104.6M)
2025-10-28	SELL	unknown	池谷正成 Masashige Ikeya	strategic	161	¥1,356	-31.3%	¥4.4B ($28.6M)
2025-10-21	SELL	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	4.6M	¥1,422	-25.2%	¥2.2B ($14.3M)
2025-10-21	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	142.0K	¥1,422	+25.2%	¥250M ($1.6M)
2025-10-21	SELL	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	692.9K	¥1,422	-25.2%	¥203M ($1.3M)
2025-04-04	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	6.2M	¥1,551	+14.8%	¥9.5B ($61.2M)
2025-04-04	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	-33.5K	¥1,551	+14.8%	-
2025-04-04	BUY	unknown	野村證券株式会社 Nomura Securities Co.,Ltd.	other	838.2K	¥1,551	+14.8%	¥1.3B ($8.4M)
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	7.3M	¥1,665	+6.9%	¥12.2B ($78.6M)
2024-04-04	SELL	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	7.4M	¥1,621	-9.8%	¥2.7B ($17.5M)
2023-03-07	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	51.3K	¥1,591	+11.9%	¥6.9B ($44.6M)
2023-03-07	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	9.1M	¥1,591	+11.9%	¥2.5B ($16.1M)
2023-01-18	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	310.2K	¥1,250	+42.4%	¥388M ($2.5M)
2023-01-18	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	7.5M	¥1,250	+42.4%	¥9.4B ($60.4M)
2022-06-21	BUY	unknown	野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd.	other	6.2M	¥1,505	+18.3%	¥9.3B ($59.8M)
2022-06-21	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	25.0K	¥1,505	+18.3%	¥3.9B ($25.1M)

Frequently asked questions

Who has been buying Tokyo Steel Manufacturing Co., Ltd. stock?: 7 distinct investors have filed 14 disclosed large-shareholding filings in Tokyo Steel Manufacturing Co., Ltd. (5423), most recently on 2026-05-13. 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 Tokyo Steel Manufacturing Co., Ltd. have?: Tokyo Steel Manufacturing Co., Ltd. has 14 buy-side and 4 sell-side disclosures on record, covering ¥55.8B ($359.9M) in total reported value, spanning 2022-06-21 to 2026-05-13.
Where does StockDrifts get Tokyo Steel Manufacturing 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 Tokyo Steel Manufacturing Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.