Who has been buying Idemitsu Kosan Co.,Ltd. stock?

20 distinct investors have filed 38 disclosed large-shareholding filings in Idemitsu Kosan Co.,Ltd. (5019), most recently on 2026-01-08. 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 Idemitsu Kosan Co.,Ltd. have?

Idemitsu Kosan Co.,Ltd. has 38 buy-side and 19 sell-side disclosures on record, covering ¥411.8B ($2.7B) in total reported value, spanning 2021-04-07 to 2026-01-08.

Where does StockDrifts get Idemitsu Kosan 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.

Idemitsu Kosan Co.,Ltd. 5019

Company

出光興産株式会社Idemitsu Kosan Co.,Ltd.

Investors

Buys

Total Value

¥411.8B ($2.7B)

Avg Return

+51.36%

Last Filing

2026-01-08

Idemitsu Kosan Co.,Ltd. (5019) has 38 disclosed large-shareholding filings and 19 disclosed disposals on record, filed by 20 distinct investors. Together those filings cover ¥411.8B ($2.7B) in reported transaction value. The earliest filing StockDrifts holds for Idemitsu Kosan Co.,Ltd. is dated 2021-04-07; the most recent is 2026-01-08. 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 +51.36%, 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
2026-08-06	SELL	unknown	野村アセットマネジメント株式会社	other	54.6M	¥1,258.5	-3.8%	¥2.0B ($12.9M)
2026-08-06	BUY	Market Buy	ノムラインターナショナルピーエルシー NOMURA INTERNATIONAL PLC	other	837.7K	¥1,258.5	+3.8%	¥1.5B ($9.9M)
2026-08-06	SELL	unknown	野村證券株式会社	other	498.7K	¥1,258.5	-3.8%	¥13.2B ($85.4M)
2026-06-09	BUY	unknown	出光千惠子	strategic	4.8M	¥1,339	-7.2%	¥6.5B ($41.6M)
2026-06-09	BUY	Market Buy	株式会社縁	strategic	17.6M	¥1,339	-7.2%	¥1.1B ($7.4M)
2026-06-09	BUY	Market Buy	株式会社善	strategic	17.8M	¥1,339	-7.2%	¥1.3B ($8.5M)
2026-06-09	BUY	Market Buy	MIパワー株式会社	strategic	12.6M	¥1,339	-7.2%	¥983M ($6.3M)
2026-06-09	BUY	Market Buy	正和興産株式会社	strategic	24.9M	¥1,339	-7.2%	¥1.6B ($10.6M)
2026-06-09	BUY	Market Buy	日章興産株式会社	strategic	109.5M	¥1,339	-7.2%	¥7.4B ($47.6M)
2026-05-28	BUY	unknown	出光千惠子	strategic	4.8M	¥1,314.5	-6.9%	¥6.3B ($40.9M)
2026-05-28	BUY	unknown	出光千惠子	strategic	4.8M	¥1,314.5	-6.9%	¥6.3B ($40.9M)
2026-05-28	BUY	unknown	日章興産株式会社	strategic	109.5M	¥1,314.5	-6.9%	¥144.0B ($928.8M)
2026-05-28	BUY	unknown	日章興産株式会社	strategic	109.5M	¥1,314.5	-6.9%	¥144.0B ($928.8M)
2026-01-08	BUY	unknown	株式会社縁	strategic	17.6M	¥1,188	-21.6%	¥25.4B ($163.9M)
2026-01-08	BUY	unknown	株式会社善	strategic	17.8M	¥1,188	-21.6%	¥25.7B ($166.0M)
2026-01-08	BUY	unknown	MIパワー株式会社	strategic	12.6M	¥1,188	-21.6%	¥18.1B ($117.0M)
2026-01-08	BUY	unknown	正和興産株式会社	strategic	24.9M	¥1,188	-21.6%	¥35.9B ($231.8M)
2026-01-08	BUY	unknown	日章興産株式会社	strategic	109.5M	¥1,188	-21.6%	¥158.2B ($1.0B)
2025-12-22	BUY	unknown	株式会社縁	strategic	17.6M	¥1,171.5	+23.3%	¥25.4B ($163.9M)
2025-12-22	BUY	unknown	株式会社善	strategic	17.8M	¥1,171.5	+23.3%	¥25.7B ($166.0M)
2025-12-22	BUY	unknown	MIパワー株式会社	strategic	12.6M	¥1,171.5	-23.3%	¥18.1B ($117.0M)
2025-12-22	BUY	unknown	正和興産株式会社	strategic	24.9M	¥1,171.5	-23.3%	¥35.9B ($231.8M)
2025-12-22	SELL	unknown	日章興産株式会社	strategic	109.5M	¥1,171.5	-23.3%	¥158.2B ($1.0B)
2025-12-22	BUY	unknown	株式会社縁	strategic	8.0M	¥1,171.5	-23.3%	¥11.6B ($74.6M)
2025-12-22	BUY	unknown	株式会社善	strategic	9.3M	¥1,171.5	-23.3%	¥13.5B ($86.9M)
2025-12-22	BUY	unknown	MIパワー株式会社	strategic	12.6M	¥1,171.5	-23.3%	¥18.1B ($117.0M)
2025-12-22	BUY	unknown	正和興産株式会社	strategic	24.9M	¥1,171.5	-23.3%	¥35.9B ($231.8M)
2025-12-22	BUY	unknown	日章興産株式会社	strategic	127.6M	¥1,171.5	-23.3%	¥184.3B ($1.2B)
2025-12-22	SELL	unknown	日章興産株式会社	strategic	109.5M	¥1,171.5	-23.3%	¥158.2B ($1.0B)
2025-12-22	BUY	unknown	株式会社縁	strategic	17.6M	¥1,171.5	+23.3%	¥25.4B ($163.9M)
2025-12-22	BUY	unknown	株式会社善	strategic	17.8M	¥1,171.5	+23.3%	¥25.7B ($166.0M)
2025-12-22	BUY	unknown	MIパワー株式会社	strategic	12.6M	¥1,171.5	-23.3%	¥18.1B ($117.0M)
2025-12-22	BUY	unknown	正和興産株式会社	strategic	24.9M	¥1,171.5	-23.3%	¥35.9B ($231.8M)
2025-12-22	BUY	unknown	株式会社縁	strategic	8.0M	¥1,171.5	-23.3%	¥11.6B ($74.6M)
2025-12-22	BUY	unknown	株式会社善	strategic	9.3M	¥1,171.5	-23.3%	¥13.5B ($86.9M)
2025-12-22	BUY	unknown	MIパワー株式会社	strategic	12.6M	¥1,171.5	-23.3%	¥18.1B ($117.0M)
2025-12-22	BUY	unknown	正和興産株式会社	strategic	24.9M	¥1,171.5	-23.3%	¥35.9B ($231.8M)
2025-12-22	BUY	unknown	日章興産株式会社	strategic	127.6M	¥1,171.5	-23.3%	¥184.3B ($1.2B)
2025-11-21	BUY	unknown	株式会社縁 En Co., Ltd.	strategic	8.0M	¥1,146.5	+26.0%	¥9.2B ($59.2M)
2025-11-21	BUY	unknown	株式会社善 Zen Co., Ltd.	strategic	9.3M	¥1,146.5	+26.0%	¥10.7B ($68.9M)
2025-11-21	BUY	unknown	MIパワー株式会社 MI Power Co., Ltd.	strategic	12.6M	¥1,146.5	+26.0%	¥1.0B ($6.7M)
2025-11-21	BUY	unknown	正和興産株式会社 Seiwa Kosan Co., Ltd.	strategic	24.9M	¥1,146.5	+26.0%	¥2.1B ($13.3M)
2025-11-21	BUY	unknown	株式会社縁 En Co., Ltd.	strategic	8.0M	¥1,146.5	+26.0%	¥9.2B ($59.2M)
2025-11-21	BUY	unknown	株式会社善 Zen Co., Ltd.	strategic	9.3M	¥1,146.5	+26.0%	¥10.7B ($68.9M)
2025-11-21	BUY	unknown	株式会社善 Zen Co., Ltd.	strategic	9.3M	¥1,146.5	+26.0%	¥10.7B ($68.9M)
2025-11-21	BUY	unknown	MIパワー株式会社 MI Power Co., Ltd.	strategic	12.6M	¥1,146.5	+26.0%	¥1.0B ($6.7M)
2025-11-21	BUY	unknown	正和興産株式会社 Seiwa Kosan Co., Ltd.	strategic	24.9M	¥1,146.5	+26.0%	¥2.1B ($13.3M)
2025-11-21	BUY	unknown	日章興産株式会社 Nissho Kosan Co., LTD.	strategic	127.6M	¥1,146.5	+26.0%	¥2.4B ($15.3M)
2025-11-21	BUY	unknown	日章興産株式会社 Nissho Kosan Co., LTD.	strategic	127.6M	¥1,146.5	+26.0%	¥2.4B ($15.3M)
2025-11-21	BUY	unknown	日章興産株式会社 Nissho Kosan Co., LTD.	strategic	127.6M	¥1,146.5	+26.0%	¥2.4B ($15.3M)

Showing the 50 most recent of 124 filings.

Frequently asked questions

Who has been buying Idemitsu Kosan Co.,Ltd. stock?: 20 distinct investors have filed 38 disclosed large-shareholding filings in Idemitsu Kosan Co.,Ltd. (5019), most recently on 2026-01-08. 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 Idemitsu Kosan Co.,Ltd. have?: Idemitsu Kosan Co.,Ltd. has 38 buy-side and 19 sell-side disclosures on record, covering ¥411.8B ($2.7B) in total reported value, spanning 2021-04-07 to 2026-01-08.
Where does StockDrifts get Idemitsu Kosan 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 Idemitsu Kosan Co.,Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.