Who has been buying MEDIA DO Co., Ltd. stock?

10 distinct investors have filed 26 disclosed large-shareholding filings in MEDIA DO Co., Ltd. (3678), most recently on 2026-04-03. 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 MEDIA DO Co., Ltd. have?

MEDIA DO Co., Ltd. has 26 buy-side and 19 sell-side disclosures on record, covering ¥10.9B ($70.3M) in total reported value, spanning 2021-03-22 to 2026-04-03.

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.

MEDIA DO Co., Ltd. 3678

Company

株式会社メディアドゥMEDIA DO Co., Ltd.

Investors

Buys

Total Value

¥10.9B ($70.3M)

Avg Return

-20.94%

Last Filing

2026-04-03

MEDIA DO Co., Ltd. (3678) has 26 disclosed large-shareholding filings and 19 disclosed disposals on record, filed by 10 distinct investors. Together those filings cover ¥10.9B ($70.3M) in reported transaction value. The earliest filing StockDrifts holds for MEDIA DO Co., Ltd. is dated 2021-03-22; the most recent is 2026-04-03. Across these filings the average return since disclosure is -20.94%, 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
2026-09-08	BUY	Market Buy	株式会社UH5	passive	35.0K	¥1,260	-	-
2026-09-08	SELL	Market Buy	株式会社UH Partners 3	passive	453.1K	¥1,260	+1.7%	¥36M ($235K)
2026-09-08	SELL	Market Buy	株式会社UH Partners 2	passive	1.1M	¥1,260	+1.7%	¥4M ($25K)
2026-09-08	SELL	Market Buy	光通信株式会社	passive	1.3M	¥1,260	+1.7%	¥4M ($25K)
2026-04-03	BUY	Market Buy	光通信株式会社	passive	1.3M	¥1,599	-22.5%	¥190M ($1.2M)
2026-04-03	BUY	Market Buy	株式会社UH Partners 2	passive	1.1M	¥1,599	-	-
2026-04-03	SELL	Market Buy	株式会社UH Partners 3	passive	480.5K	¥1,599	+22.5%	¥250M ($1.6M)
2026-04-03	BUY	Market Buy	株式会社UH5	passive	35.0K	¥1,599	-	-
2025-12-11	BUY	Market Buy	株式会社UH Partners 3	passive	636.6K	¥1,706	-27.4%	¥244M ($1.6M)
2025-12-11	BUY	Market Buy	株式会社UH5	passive	35.0K	¥1,706	-	-
2025-12-11	BUY	Market Buy	株式会社UH Partners 2	passive	1.1M	¥1,706	-	-
2025-12-11	BUY	Market Buy	光通信株式会社	passive	1.2M	¥1,706	-27.4%	¥26M ($167K)
2025-11-07	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,755	-	-
2025-11-07	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	1.1M	¥1,755	-	-
2025-11-07	BUY	Market Buy	株式会社UH5 UH5 Co., Ltd.	passive	35.0K	¥1,755	-	-
2025-11-07	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	493.5K	¥1,755	-29.4%	¥278M ($1.8M)
2025-10-23	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,873	-	-
2025-10-23	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	1.1M	¥1,873	-	-
2025-10-23	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	336.6K	¥1,873	-33.9%	¥271M ($1.7M)
2025-10-23	BUY	Market Buy	株式会社UH5 UH5 Co., Ltd.	passive	35.0K	¥1,873	-	¥66M ($423K)
2025-09-26	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,929	-	-
2025-09-26	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	191.6K	¥1,929	-35.8%	¥53M ($341K)
2025-09-26	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	1.1M	¥1,929	-	-
2025-09-09	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	1.1M	¥1,925	-	-
2025-09-09	BUY	Market Buy	株式会社UH Partners 3 UH Partners 3 Co., Ltd.	passive	164.3K	¥1,925	-	¥316M ($2.0M)
2025-09-09	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,925	-	-
2025-07-23	SELL	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,733	+28.5%	¥5M ($34K)
2025-07-23	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	1.1M	¥1,733	-28.5%	¥274M ($1.8M)
2025-04-14	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,698	-	-
2025-04-14	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	974.7K	¥1,698	-27.0%	¥294M ($1.9M)
2024-12-20	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,419	-	-
2024-12-20	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	801.0K	¥1,419	-12.7%	¥228M ($1.5M)
2024-08-22	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,490	-	-
2024-08-22	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	639.6K	¥1,490	-16.9%	¥235M ($1.5M)
2024-08-02	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,281	-	-
2024-08-02	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	482.2K	¥1,281	-3.3%	¥200M ($1.3M)
2024-07-23	SELL	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,385	+10.5%	¥4M ($27K)
2024-07-23	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	326.6K	¥1,385	-10.5%	¥288M ($1.9M)
2024-05-09	BUY	Market Buy	株式会社UH Partners 2 UH Partners 2, Inc.	passive	118.1K	¥1,392	-	¥164M ($1.1M)
2024-05-09	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,392	-11.0%	¥82M ($530K)
2024-04-30	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	1.1M	¥1,362	-9.0%	¥225M ($1.4M)
2024-04-19	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	923.7K	¥1,320	-6.1%	¥214M ($1.4M)
2024-03-21	BUY	Market Buy	光通信株式会社 Hikari Tsushin K.K.	passive	760.6K	¥1,425	-13.1%	¥1.1B ($7.0M)
2024-01-24	SELL	Market Buy	株式会社FIBC FIBC Co., Ltd.	activist	1.7M	¥1,352	+8.4%	¥6M ($40K)
2024-01-24	BUY	unknown	株式会社FIBC FIBC Co., Ltd.	activist	1.7M	¥1,352	-	-
2024-01-24	BUY	unknown	藤田恭嗣 Fujita Yasushi	activist	2.5M	¥1,352	-	-
2024-01-24	BUY	Market Buy	藤田恭嗣 Fujita Yasushi	activist	2.5M	¥1,352	-8.4%	¥12M ($79K)
2023-12-13	BUY	unknown	藤田恭嗣 Fujita Yasushi	activist	2.5M	¥1,409	-12.1%	¥13M ($83K)
2023-12-13	BUY	Market Buy	藤田恭嗣 Fujita Yasushi	activist	2.5M	¥1,409	-12.1%	¥13M ($83K)
2023-12-13	BUY	Market Buy	藤田恭嗣 Fujita Yasushi	activist	2.5M	¥1,409	-12.1%	¥13M ($83K)

Showing the 50 most recent of 71 filings.

Frequently asked questions

Who has been buying MEDIA DO Co., Ltd. stock?: 10 distinct investors have filed 26 disclosed large-shareholding filings in MEDIA DO Co., Ltd. (3678), most recently on 2026-04-03. 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 MEDIA DO Co., Ltd. have?: MEDIA DO Co., Ltd. has 26 buy-side and 19 sell-side disclosures on record, covering ¥10.9B ($70.3M) in total reported value, spanning 2021-03-22 to 2026-04-03.
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.