Who has been buying Tsukuruba Inc. stock?

13 distinct investors have filed 13 disclosed large-shareholding filings in Tsukuruba Inc. (2978), most recently on 2026-05-08. 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 Tsukuruba Inc. have?

Tsukuruba Inc. has 13 buy-side and 40 sell-side disclosures on record, covering ¥3.3B ($21.6M) in total reported value, spanning 2021-04-01 to 2026-05-08.

Where does StockDrifts get Tsukuruba Inc. 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.

Tsukuruba Inc. 2978

Company

株式会社ツクルバTsukuruba Inc.

Investors

Buys

Total Value

¥3.3B ($21.6M)

Avg Return

-25.79%

Last Filing

2026-05-08

Tsukuruba Inc. (2978) has 13 disclosed large-shareholding filings and 40 disclosed disposals on record, filed by 13 distinct investors. Together those filings cover ¥3.3B ($21.6M) in reported transaction value. The earliest filing StockDrifts holds for Tsukuruba Inc. is dated 2021-04-01; the most recent is 2026-05-08. 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 -25.79%, 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
2026-05-08	SELL	unknown	株式会社エイチ	strategic	1.2M	¥420	+11.4%	¥14M ($88K)
2026-05-08	SELL	unknown	村上浩輝	strategic	2.2M	¥420	+11.4%	¥46M ($297K)
2026-04-22	BUY	Market Buy	合同会社PKSHA Technology Capital代表社員株式会社PKSHA Technology職務執行者久保田潤至	passive	86.0K	¥408	-4.4%	¥35M ($226K)
2026-04-22	BUY	Market Buy	株式会社PKSHA Technology代表取締役上野山勝也	strategic	1.2M	¥408	-4.4%	¥131M ($843K)
2026-04-03	BUY	Market Buy	村上浩輝	strategic	2.3M	¥425	-0.2%	¥4M ($26K)
2026-04-03	BUY	Market Buy	株式会社エイチ	strategic	1.2M	¥425	-0.2%	¥496M ($3.2M)
2026-03-24	BUY	unknown	合同会社PKSHA Technology Capital代表社員株式会社PKSHA Technology職務執行者久保田潤至	passive	86.0K	¥432	-3.9%	¥36M ($230K)
2026-03-24	BUY	unknown	株式会社PKSHA Technology代表取締役上野山勝也	strategic	894.7K	¥432	-3.9%	¥371M ($2.4M)
2026-03-24	BUY	unknown	合同会社PKSHA Technology Capital	passive	86.0K	¥432	-3.9%	¥36M ($230K)
2026-03-24	BUY	unknown	株式会社PKSHA Technology	strategic	894.7K	¥432	-3.9%	¥371M ($2.4M)
2026-03-19	SELL	unknown	合同会社エム	strategic	495.5K	¥441	+5.9%	¥206M ($1.3M)
2026-03-19	SELL	unknown	中村真広	strategic	350.0K	¥441	+5.9%	¥145M ($937K)
2026-03-19	SELL	unknown	合同会社エム	strategic	495.5K	¥441	+5.9%	¥206M ($1.3M)
2026-03-19	SELL	unknown	中村真広	strategic	350.0K	¥441	+5.9%	¥145M ($937K)
2026-02-13	BUY	unknown	竹内真 Shin Takeuchi	activist	720.2K	¥448	-7.4%	¥323M ($2.1M)
2026-01-28	SELL	unknown	合同会社エム	strategic	885.0K	¥455	+8.8%	¥367M ($2.4M)
2026-01-28	SELL	unknown	中村真広	strategic	800.5K	¥455	+8.8%	¥332M ($2.1M)
2026-01-23	BUY	unknown	株式会社エイチ	strategic	1.2M	¥465	+10.8%	¥485M ($3.1M)
2026-01-23	BUY	unknown	村上浩輝	strategic	2.3M	¥465	+10.8%	¥936M ($6.0M)
2025-09-26	SELL	unknown	株式会社エイチ H Co., Ltd.	activist	1.2M	¥589	+29.5%	¥1M ($9K)
2025-09-26	SELL	unknown	株式会社エイチ H Co., Ltd.	activist	1.2M	¥589	+29.5%	¥1M ($9K)
2025-09-26	SELL	unknown	村上浩輝 Hiroki Murakami	strategic	2.3M	¥589	+29.5%	¥6M ($36K)
2025-09-26	SELL	unknown	村上浩輝 Hiroki Murakami	strategic	2.3M	¥589	+29.5%	¥6M ($36K)
2024-12-25	SELL	unknown	合同会社エム M LLC	strategic	885.0K	¥753	+44.9%	¥2K ($11)
2024-12-25	SELL	unknown	中村真広 Masahiro Nakamura	strategic	814.0K	¥753	+44.9%	¥125K ($808)
2024-12-18	SELL	Market Buy	株式会社エイチ H Co., Ltd.	activist	1.2M	¥767	+45.9%	¥5M ($35K)
2024-12-18	BUY	Market Buy	村上浩輝 Hiroki Murakami	strategic	2.3M	¥767	-45.9%	¥87M ($562K)
2024-04-05	SELL	unknown	合同会社エム M LLC	strategic	885.0K	¥953	+56.5%	¥1M ($7K)
2024-04-05	SELL	unknown	中村真広 Masahiro Nakamura	strategic	979.1K	¥953	+56.5%	¥45M ($287K)
2024-01-10	SELL	unknown	合同会社エム M LLC	strategic	885.0K	¥810	+48.8%	¥945K ($6K)
2024-01-10	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.0M	¥810	+48.8%	¥100M ($646K)
2023-09-19	SELL	unknown	合同会社エム M LLC	activist	885.0K	¥1,063	+61.0%	¥80M ($519K)
2023-09-19	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.1M	¥1,063	+61.0%	¥61M ($391K)
2023-03-10	SELL	unknown	合同会社エム M LLC	activist	950.0K	¥734	+43.5%	¥4M ($27K)
2023-03-10	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.2M	¥734	+43.5%	¥81M ($523K)
2022-11-22	SELL	unknown	株式会社丸井グループ MARUI GROUP CO.,LTD.	strategic	700	¥913	+54.5%	¥587M ($3.8M)
2022-03-17	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.3M	¥626	+33.7%	¥5M ($32K)
2022-03-17	SELL	unknown	合同会社エム M LLC	activist	950.0K	¥626	+33.7%	¥4M ($23K)
2022-02-02	SELL	unknown	株式会社エイチ H Co., Ltd.	activist	1.1M	¥582	+28.7%	¥663K ($4K)
2022-02-02	SELL	unknown	村上浩輝 Hiroki Murakami	strategic	2.1M	¥582	+28.7%	¥1M ($9K)
2022-01-11	SELL	Market Buy	みずほ信託銀行株式会社 Mizuho Trust & Banking Co., Ltd.	unknown	0	¥762	+45.5%	¥46M ($297K)
2022-01-11	BUY	Market Buy	みずほ証券株式会社 Mizuho Securities Co., Ltd.	other	32.7K	¥762	-45.5%	¥25M ($161K)
2022-01-11	BUY	Market Buy	アセットマネジメントOne株式会社 Asset Management One Co., Ltd.	other	771.7K	¥762	-45.5%	¥89M ($571K)
2021-11-05	SELL	unknown	株式会社エイチ H Co., Ltd.	activist	1.1M	¥1,083	+61.7%	¥153M ($986K)
2021-11-05	SELL	unknown	村上浩輝 Hiroki Murakami	strategic	2.1M	¥1,083	+61.7%	¥123M ($795K)
2021-09-28	SELL	unknown	合同会社エム M LLC	activist	950.0K	¥1,001	+58.5%	¥50M ($323K)
2021-09-28	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.3M	¥1,001	+58.5%	¥150M ($970K)
2021-09-21	SELL	unknown	合同会社エム M LLC	activist	1.0M	¥1,092	+62.0%	¥173M ($1.1M)
2021-09-21	SELL	unknown	中村真広 Masahiro Nakamura	strategic	1.4M	¥1,092	+62.0%	¥342M ($2.2M)
2021-09-10	SELL	unknown	株式会社エイチ H Co., Ltd.	activist	1.0M	¥1,140	+63.6%	¥36M ($231K)

Showing the 50 most recent of 59 filings.

Frequently asked questions

Who has been buying Tsukuruba Inc. stock?: 13 distinct investors have filed 13 disclosed large-shareholding filings in Tsukuruba Inc. (2978), most recently on 2026-05-08. 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 Tsukuruba Inc. have?: Tsukuruba Inc. has 13 buy-side and 40 sell-side disclosures on record, covering ¥3.3B ($21.6M) in total reported value, spanning 2021-04-01 to 2026-05-08.
Where does StockDrifts get Tsukuruba Inc. 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 Tsukuruba Inc.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.