Who has been buying NHK Spring Co., Ltd. stock?

13 distinct investors have filed 10 disclosed large-shareholding filings in NHK Spring Co., Ltd. (5991), most recently on 2025-12-19. 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 NHK Spring Co., Ltd. have?

NHK Spring Co., Ltd. has 10 buy-side and 15 sell-side disclosures on record, covering ¥11.0B ($70.9M) in total reported value, spanning 2021-03-18 to 2025-12-19.

Where does StockDrifts get NHK Spring 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.

NHK Spring Co., Ltd. 5991

Company

日本発條株式会社NHK Spring Co., Ltd.

Investors

Buys

Total Value

¥11.0B ($70.9M)

Avg Return

+94.02%

Last Filing

2025-12-19

NHK Spring Co., Ltd. (5991) has 10 disclosed large-shareholding filings and 15 disclosed disposals on record, filed by 13 distinct investors. Together those filings cover ¥11.0B ($70.9M) in reported transaction value. The earliest filing StockDrifts holds for NHK Spring Co., Ltd. is dated 2021-03-18; the most recent is 2025-12-19. 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 +94.02%, 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
2026-07-07	BUY	Market Buy	アセットマネジメントOne株式会社	other	7.3M	¥3,912	-3.8%	¥5.6B ($36.2M)
2026-07-07	BUY	unknown	みずほ信託銀行株式会社	other	1.0M	¥3,912	-3.8%	¥4.0B ($25.9M)
2026-07-07	BUY	Market Buy	株式会社みずほ銀行	other	5.8M	¥3,912	-3.8%	¥1.2B ($7.6M)
2026-07-07	SELL	unknown	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	136.2K	¥3,912	+3.8%	¥1.1B ($7.0M)
2025-12-19	BUY	unknown	野村アセットマネジメント株式会社	other	11.3M	¥2,494	+3.0%	¥29.1B ($188.0M)
2025-12-19	BUY	unknown	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	223.9K	¥2,494	+3.0%	¥575M ($3.7M)
2025-12-19	BUY	unknown	野村證券株式会社	other	251.7K	¥2,494	+3.0%	¥646M ($4.2M)
2025-04-02	SELL	negotiated	大同特殊鋼株式会社 Daido Steel Co., Ltd.	strategic	22.4M	¥1,625	-58.0%	¥5.8B ($37.6M)
2025-04-02	BUY	negotiated	大同興業株式会社 Daido Kogyo Co., Ltd.	other	2.3M	¥1,625	+58.0%	¥3.7B ($23.7M)
2025-02-27	BUY	negotiated	大同興業株式会社 Daido Kogyo Co., Ltd.	other	2.3M	¥1,718	+49.5%	¥3.9B ($25.0M)
2025-02-27	SELL	negotiated	大同特殊鋼株式会社 Daido Steel Co., Ltd.	strategic	26.0M	¥1,718	-49.5%	¥4.2B ($27.3M)
2025-01-23	BUY	negotiated	大同興業株式会社 Daido Kogyo Co., Ltd.	other	2.3M	¥1,999	+28.5%	¥4.5B ($29.1M)
2025-01-23	SELL	negotiated	大同特殊鋼株式会社 Daido Steel Co., Ltd.	strategic	28.4M	¥1,999	-28.5%	¥4.9B ($31.8M)
2024-11-22	BUY	unknown	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	435.7K	¥1,799.5	+42.7%	¥784M ($5.1M)
2024-11-22	BUY	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	6.2M	¥1,799.5	+42.7%	¥11.1B ($71.9M)
2024-11-22	BUY	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	other	5.8M	¥1,799.5	+42.7%	¥10.4B ($66.8M)
2024-10-30	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	12.2M	¥1,887.5	-36.0%	¥4.9B ($31.8M)
2024-10-04	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	14.8M	¥1,854.5	-38.5%	¥4.8B ($30.7M)
2024-09-20	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	17.4M	¥1,786	-43.8%	¥4.6B ($29.8M)
2024-05-27	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	20.0M	¥1,885.5	-36.2%	¥4.7B ($30.6M)
2024-03-05	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	22.5M	¥1,447	-77.5%	¥3.6B ($23.2M)
2024-02-16	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	25.0M	¥1,447.5	-77.4%	¥3.6B ($23.2M)
2023-03-23	SELL	unknown	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	4.8M	¥915	-180.7%	¥1.3B ($8.2M)
2023-03-23	SELL	unknown	株式会社みずほ銀行 Mizuho Bank, Ltd.	strategic	7.3M	¥915	-180.7%	¥1.4B ($8.8M)
2022-11-21	SELL	negotiated	三菱UFJ国際投信株式会社 Mitsubishi UFJ Financial Group Inc.	passive	1.2M	¥907	-183.1%	¥1.5B ($10.0M)
2022-11-21	BUY	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	5.5M	¥907	+183.1%	¥4.9B ($31.9M)
2022-11-21	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	1.4M	¥907	+183.1%	¥1.3B ($8.2M)
2022-11-11	BUY	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	27.5M	¥895	+186.9%	¥2.2B ($14.4M)
2022-08-01	BUY	negotiated	株式会社三菱UFJ銀行 Mitsubishi UFJ Financial Group Inc.	strategic	1.4M	¥931	+175.8%	¥1.3B ($8.5M)
2022-08-01	SELL	negotiated	エム・ユー投資顧問株式会社 M.U. Investment Advisors Co., Ltd.	passive	200	¥931	-175.8%	¥614M ($4.0M)
2022-08-01	BUY	negotiated	三菱UFJ国際投信株式会社 Mitsubishi UFJ Financial Group Inc.	passive	2.9M	¥931	+175.8%	¥2.4B ($15.4M)
2022-08-01	SELL	negotiated	三菱UFJ信託銀行株式会社 Mitsubishi UFJ Financial Group Inc.	passive	8.3M	¥931	-175.8%	¥1.4B ($9.2M)
2022-01-14	SELL	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	25.0M	¥998	-157.3%	¥2.6B ($16.7M)
2021-03-18	BUY	subscription	シルチェスター・インターナショナル・インベスターズ・エルエルピー (Silchester International Investors LLP) Silchester International Investors LLP	activist	27.5M	¥718.756	+257.3%	¥1.8B ($11.4M)

Frequently asked questions

Who has been buying NHK Spring Co., Ltd. stock?: 13 distinct investors have filed 10 disclosed large-shareholding filings in NHK Spring Co., Ltd. (5991), most recently on 2025-12-19. 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 NHK Spring Co., Ltd. have?: NHK Spring Co., Ltd. has 10 buy-side and 15 sell-side disclosures on record, covering ¥11.0B ($70.9M) in total reported value, spanning 2021-03-18 to 2025-12-19.
Where does StockDrifts get NHK Spring 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 NHK Spring Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.