Who has been buying UMC Electronics Co., Ltd. stock?

9 distinct investors have filed 6 disclosed large-shareholding filings in UMC Electronics Co., Ltd. (6615), 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 UMC Electronics Co., Ltd. have?

UMC Electronics Co., Ltd. has 6 buy-side and 3 sell-side disclosures on record, covering ¥11.2B ($72.1M) in total reported value, spanning 2021-03-30 to 2026-05-13.

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.

UMC Electronics Co., Ltd. 6615

Company

ユー・エム・シー・エレクトロニクス株式会社UMC Electronics Co., Ltd.

Investors

Buys

Total Value

¥11.2B ($72.1M)

Avg Return

-32.59%

Last Filing

2026-05-13

UMC Electronics Co., Ltd. (6615) has 6 disclosed large-shareholding filings and 3 disclosed disposals on record, filed by 9 distinct investors. Together those filings cover ¥11.2B ($72.1M) in reported transaction value. The earliest filing StockDrifts holds for UMC Electronics Co., Ltd. is dated 2021-03-30; the most recent is 2026-05-13. Across these filings the average return since disclosure is -32.59%, 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
2026-09-04	SELL	unknown	アセットマネジメントOne株式会社	other	139.9K	¥240	+0.0%	¥7M ($48K)
2026-09-04	SELL	unknown	みずほ信託銀行株式会社	unknown	0	¥240	+0.0%	¥18M ($118K)
2026-09-04	SELL	unknown	株式会社みずほ銀行	strategic	21.6M	¥240	+0.0%	¥51M ($328K)
2026-05-13	BUY	unknown	アセットマネジメントOne株式会社	other	193.7K	¥312	-23.1%	¥60M ($390K)
2026-05-13	BUY	unknown	株式会社みずほ銀行	strategic	22.2M	¥312	-23.1%	¥6.9B ($44.8M)
2026-05-13	BUY	unknown	みずほ信託銀行株式会社	other	137.8K	¥312	-23.1%	¥43M ($277K)
2021-04-08	BUY	unknown	株式会社アイシン AISIN CORPORATION	other	2.2M	¥1,011	-	-
2021-03-31	BUY	unknown	アイシン精機株式会社 AISIN SEIKI CO., LTD.	other	2.2M	¥869.293	-	¥1.9B ($12.4M)
2021-03-31	BUY	unknown	株式会社ネクスティエレクトロニクス NEXTY Electronics Corporation	other	2.2M	¥869.293	-72.4%	¥1.9B ($12.4M)
2021-03-31	BUY	unknown	アイシン精機株式会社 AISIN SEIKI CO., LTD.	other	2.2M	¥869.293	-72.4%	¥1.9B ($12.4M)
2021-03-31	BUY	Market Buy	株式会社豊田自動織機 TOYOTA INDUSTRIES CORPORATION	strategic	9.8M	¥869.293	-72.4%	¥7.3B ($47.0M)
2021-03-30	SELL	private	O・ウチヤマ・ホールディングス有限会社 O-Uchiyama Holdings Ltd.	strategic	626.8K	¥921.413	+74.0%	¥578M ($3.7M)
2021-03-30	SELL	private	H・ウチヤマ・ホールディングス有限会社 H-Uchiyama Holdings Ltd.	strategic	741.4K	¥921.413	+74.0%	¥684M ($4.4M)
2021-03-30	SELL	private	S・ウチヤマ・ホールディングス有限会社 S-Uchiyama Holdings Ltd.	strategic	721.1K	¥921.413	+74.0%	¥2.7B ($17.1M)

Frequently asked questions

Who has been buying UMC Electronics Co., Ltd. stock?: 9 distinct investors have filed 6 disclosed large-shareholding filings in UMC Electronics Co., Ltd. (6615), 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 UMC Electronics Co., Ltd. have?: UMC Electronics Co., Ltd. has 6 buy-side and 3 sell-side disclosures on record, covering ¥11.2B ($72.1M) in total reported value, spanning 2021-03-30 to 2026-05-13.
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.