Who has been buying Welby Inc. stock?

7 distinct investors have filed 4 disclosed large-shareholding filings in Welby Inc. (4438), most recently on 2026-03-18. 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 Welby Inc. have?

Welby Inc. has 4 buy-side and 5 sell-side disclosures on record, covering ¥2.1B ($13.7M) in total reported value, spanning 2021-09-24 to 2026-03-18.

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.

Welby Inc. 4438

Company

株式会社WelbyWelby Inc.

Investors

Buys

Total Value

¥2.1B ($13.7M)

Avg Return

-31.02%

Last Filing

2026-03-18

Welby Inc. (4438) has 4 disclosed large-shareholding filings and 5 disclosed disposals on record, filed by 7 distinct investors. Together those filings cover ¥2.1B ($13.7M) in reported transaction value. The earliest filing StockDrifts holds for Welby Inc. is dated 2021-09-24; the most recent is 2026-03-18. Across these filings the average return since disclosure is -31.02%, 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
2026-03-18	SELL	Market Buy	マイルストーン・キャピタル・マネジメント株式会社 Milestone Capital Management,Ltd.	passive	2.0M	¥368	+24.7%	¥8M ($54K)
2025-12-04	BUY	Market Buy	マイルストーン・キャピタル・マネジメント株式会社 Milestone Capital Management,Ltd.	passive	2.1M	¥283	-2.1%	¥583M ($3.8M)
2025-04-04	SELL	unknown	比木武 Takeru Hiki	activist	2.9M	¥302	+8.3%	¥16M ($105K)
2025-04-04	BUY	unknown	比木武 Takeru Hiki	activist	3.0M	¥302	-	¥5M ($32K)
2024-08-23	SELL	unknown	比木武 Takeru Hiki	activist	3.0M	¥437	+36.6%	¥85M ($545K)
2024-05-08	BUY	unknown	中部電力株式会社 Chubu Electric Power Company, Incorporated	strategic	434.8K	¥560	-50.5%	¥243M ($1.6M)
2023-11-14	SELL	negotiated	株式会社デジタルガレージ Digital Garage, Inc.	strategic	180.0K	¥532	+47.9%	¥706M ($4.6M)
2023-11-14	BUY	unknown	株式会社スズケン SUZUKEN CO.,LTD.	other	1.7M	¥532	-47.9%	¥882M ($5.7M)
2022-11-18	SELL	unknown	比木武 Takeru Hiki	activist	3.0M	¥470	+41.1%	¥163M ($1.1M)
2021-09-24	BUY	unknown	株式会社ブライトリンクパートナーズ Brightlink Partners Co., Ltd.	strategic	449.3K	¥941	-70.6%	¥418M ($2.7M)
2021-09-24	BUY	unknown	中島正和 Masakazu Nakajima	strategic	32.0K	¥941	-	-

Frequently asked questions

Who has been buying Welby Inc. stock?: 7 distinct investors have filed 4 disclosed large-shareholding filings in Welby Inc. (4438), most recently on 2026-03-18. 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 Welby Inc. have?: Welby Inc. has 4 buy-side and 5 sell-side disclosures on record, covering ¥2.1B ($13.7M) in total reported value, spanning 2021-09-24 to 2026-03-18.
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.