Who has been buying Medical System Network Co., Ltd. stock?

4 distinct investors have filed 4 disclosed large-shareholding filings in Medical System Network Co., Ltd. (4350), most recently on 2026-03-30. 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 Medical System Network Co., Ltd. have?

Medical System Network Co., Ltd. has 4 buy-side and 6 sell-side disclosures on record, covering ¥1.1B ($7.4M) in total reported value, spanning 2021-05-26 to 2026-03-30.

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.

Medical System Network Co., Ltd. 4350

Company

株式会社メディカルシステムネットワークMedical System Network Co., Ltd.

Investors

Buys

Total Value

¥1.1B ($7.4M)

Avg Return

+5.57%

Last Filing

2026-03-30

Medical System Network Co., Ltd. (4350) has 4 disclosed large-shareholding filings and 6 disclosed disposals on record, filed by 4 distinct investors. Together those filings cover ¥1.1B ($7.4M) in reported transaction value. The earliest filing StockDrifts holds for Medical System Network Co., Ltd. is dated 2021-05-26; the most recent is 2026-03-30. Across these filings the average return since disclosure is +5.57%, 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
2026-09-14	BUY	Market Buy	株式会社UH6	passive	112.1K	¥500	-	-
2026-09-14	BUY	Market Buy	株式会社UH Partners 2	passive	1.4M	¥500	+4.6%	¥155M ($998K)
2026-09-14	BUY	Market Buy	光通信株式会社	passive	2.2M	¥500	-	-
2026-08-24	BUY	Market Buy	光通信株式会社	passive	2.2M	¥487	-	-
2026-08-24	BUY	Market Buy	株式会社UH Partners 2	passive	1.1M	¥487	+7.4%	¥154M ($992K)
2026-08-24	BUY	Market Buy	株式会社UH6	passive	112.1K	¥487	-	-
2026-07-30	BUY	Market Buy	光通信株式会社	passive	2.2M	¥480	-	-
2026-07-30	BUY	Market Buy	株式会社UH Partners 2	passive	771.3K	¥480	+9.0%	¥150M ($968K)
2026-07-30	BUY	Market Buy	株式会社UH6	passive	112.1K	¥480	-	-
2026-06-19	BUY	Market Buy	株式会社UH6	passive	112.1K	¥473	-	-
2026-06-19	BUY	Market Buy	株式会社UH Partners 2	passive	458.8K	¥473	+10.6%	¥148M ($954K)
2026-06-19	BUY	Market Buy	光通信株式会社	passive	2.2M	¥473	-	-
2026-05-22	BUY	Market Buy	光通信株式会社	passive	2.2M	¥486	+7.6%	¥94M ($605K)
2026-05-22	BUY	Market Buy	株式会社UH Partners 2	passive	145.9K	¥486	-	¥71M ($457K)
2026-05-22	BUY	Market Buy	株式会社UH6	passive	112.1K	¥486	-	-
2026-03-30	BUY	Market Buy	光通信株式会社	passive	2.1M	¥546	-4.2%	¥167M ($1.1M)
2026-03-30	SELL	Market Buy	株式会社UH5	unknown	0	¥546	+4.2%	¥62M ($399K)
2026-03-30	BUY	Market Buy	株式会社UH6	passive	112.1K	¥546	-	¥61M ($395K)
2026-02-17	BUY	Market Buy	株式会社UH5	passive	112.1K	¥520	-	-
2026-02-17	BUY	Market Buy	光通信株式会社	passive	1.7M	¥520	+0.6%	¥166M ($1.1M)
2025-10-16	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.4M	¥469	+11.5%	¥669M ($4.3M)
2025-10-16	BUY	Market Buy	株式会社UH5 UH5 Co., Ltd.	passive	112.1K	¥469	+11.5%	¥53M ($339K)
2025-02-20	SELL	Market Buy	サマランユーシッツ(SAMARANG UCITS) SAMARANG UCITS	passive	1.5M	¥407	-28.5%	¥128M ($829K)
2023-06-22	SELL	Market Buy	サマランユーシッツ(SAMARANG UCITS) SAMARANG UCITS	passive	1.8M	¥371	-41.0%	¥116M ($748K)
2023-02-28	SELL	Market Buy	サマランユーシッツ(SAMARANG UCITS) SAMARANG UCITS	passive	2.1M	¥411	-27.3%	¥133M ($861K)
2022-08-22	SELL	Market Buy	サマランユーシッツ(SAMARANG UCITS) SAMARANG UCITS	passive	2.4M	¥430	-21.6%	¥136M ($876K)
2021-05-26	SELL	Market Buy	サマランユーシッツ(SAMARANG UCITS) SAMARANG UCITS	passive	2.7M	¥746	+29.9%	¥279M ($1.8M)

Frequently asked questions

Who has been buying Medical System Network Co., Ltd. stock?: 4 distinct investors have filed 4 disclosed large-shareholding filings in Medical System Network Co., Ltd. (4350), most recently on 2026-03-30. 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 Medical System Network Co., Ltd. have?: Medical System Network Co., Ltd. has 4 buy-side and 6 sell-side disclosures on record, covering ¥1.1B ($7.4M) in total reported value, spanning 2021-05-26 to 2026-03-30.
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.