Who has been buying EM Systems Co., Ltd. stock?

7 distinct investors have filed 13 disclosed large-shareholding filings in EM Systems Co., Ltd. (4820), most recently on 2025-05-12. 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 EM Systems Co., Ltd. have?

EM Systems Co., Ltd. has 13 buy-side and 11 sell-side disclosures on record, covering ¥5.7B ($36.8M) in total reported value, spanning 2021-09-14 to 2025-05-12.

Where does StockDrifts get EM Systems 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.

EM Systems Co., Ltd. 4820

Company

株式会社イーエムシステムズ(商号株式会社EMシステムズ)EM Systems Co., Ltd.

Investors

Buys

Total Value

¥5.7B ($36.8M)

Avg Return

-11.55%

Last Filing

2025-05-12

EM Systems Co., Ltd. (4820) has 13 disclosed large-shareholding filings and 11 disclosed disposals on record, filed by 7 distinct investors. Together those filings cover ¥5.7B ($36.8M) in reported transaction value. The earliest filing StockDrifts holds for EM Systems Co., Ltd. is dated 2021-09-14; the most recent is 2025-05-12. 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 -11.55%, 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
2025-05-12	SELL	negotiated	國光浩三 Kozo Kunimitsu	activist	204.0K	¥764	+11.5%	¥13.5B ($86.9M)
2025-05-12	BUY	Market Buy	國光京子 Kyoko Kunimitsu	strategic	48.0K	¥764	-11.5%	¥539M ($3.5M)
2025-05-12	BUY	Market Buy	株式会社コッコウ Kokkou Co., Ltd.	strategic	26.0M	¥764	-11.5%	¥1.2B ($7.8M)
2025-05-12	BUY	Market Buy	國光宏昌 Hiromasa Kunimitsu	activist	2.1M	¥764	-11.5%	¥124M ($799K)
2025-05-12	BUY	negotiated	株式会社コッコウ Kokkou Co., Ltd.	strategic	26.0M	¥764	-11.5%	¥1.2B ($7.8M)
2025-05-12	BUY	negotiated	國光京子 Kyoko Kunimitsu	strategic	48.0K	¥764	-11.5%	¥539M ($3.5M)
2025-05-12	BUY	negotiated	國光宏昌 Hiromasa Kunimitsu	activist	2.1M	¥764	-11.5%	¥124M ($799K)
2025-05-12	SELL	Market Buy	國光浩三 Kozo Kunimitsu	activist	204.0K	¥764	+11.5%	¥13.5B ($86.9M)
2024-05-29	BUY	Market Buy	株式会社ヴァレックス・パートナーズ VARECS Partners Limited	activist	8.6M	¥626	+8.0%	¥480M ($3.1M)
2024-01-11	BUY	Market Buy	株式会社ヴァレックス・パートナーズ VARECS Partners Limited	activist	7.8M	¥726	-6.9%	¥3.0B ($19.1M)
2024-01-11	SELL	unknown	ユナイテッド・マネージャーズ・ジャパン株式会社 United Managers Japan Inc.	unknown	0	¥726	+6.9%	¥2.7B ($17.5M)
2023-11-16	SELL	negotiated	株式会社メディパルホールディングス MEDIPAL HOLDINGS CORPORATION	strategic	7.1M	¥648	-4.3%	¥241M ($1.6M)
2023-08-25	BUY	Market Buy	株式会社ヴァレックス・パートナーズ VARECS Partners Limited	activist	3.7M	¥705	-4.1%	¥2.6B ($17.0M)
2023-01-12	BUY	Market Buy	ユナイテッド・マネージャーズ・ジャパン株式会社 United Managers Japan Inc.	activist	3.7M	¥866	-21.9%	¥3.2B ($20.8M)
2022-11-21	SELL	Market Buy	ユナイテッド・マネージャーズ・ジャパン株式会社 United Managers Japan Inc.	activist	3.7M	¥961	+29.7%	¥7M ($46K)
2022-04-07	BUY	Market Buy	ユナイテッド・マネージャーズ・ジャパン株式会社 United Managers Japan Inc.	activist	3.7M	¥798	-15.3%	¥3.0B ($19.2M)
2021-09-14	BUY	negotiated	株式会社コッコウ Kokkou Co., Ltd.	strategic	25.8M	¥849	-20.4%	¥329M ($2.1M)
2021-09-14	SELL	negotiated	國光京子 Kyoko Kunimitsu	strategic	48.0K	¥849	+20.4%	¥633M ($4.1M)
2021-09-14	SELL	negotiated	國光宏昌 Hiromasa Kunimitsu	activist	2.0M	¥849	+20.4%	¥38M ($245K)
2021-09-14	BUY	negotiated	株式会社コッコウ Kokkou Co., Ltd.	strategic	25.8M	¥849	-20.4%	¥329M ($2.1M)
2021-09-14	SELL	negotiated	國光京子 Kyoko Kunimitsu	strategic	48.0K	¥849	+20.4%	¥633M ($4.1M)
2021-09-14	SELL	negotiated	國光宏昌 Hiromasa Kunimitsu	activist	2.0M	¥849	+20.4%	¥38M ($245K)
2021-09-14	SELL	negotiated	國光浩三 Kozo Kunimitsu	activist	404.0K	¥849	+20.4%	¥968M ($6.2M)
2021-09-14	SELL	negotiated	國光浩三 Kozo Kunimitsu	activist	404.0K	¥849	+20.4%	¥968M ($6.2M)

Frequently asked questions

Who has been buying EM Systems Co., Ltd. stock?: 7 distinct investors have filed 13 disclosed large-shareholding filings in EM Systems Co., Ltd. (4820), most recently on 2025-05-12. 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 EM Systems Co., Ltd. have?: EM Systems Co., Ltd. has 13 buy-side and 11 sell-side disclosures on record, covering ¥5.7B ($36.8M) in total reported value, spanning 2021-09-14 to 2025-05-12.
Where does StockDrifts get EM Systems 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 EM Systems Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.