Who has been buying Buffalo Inc. stock?

4 distinct investors have filed 24 disclosed large-shareholding filings in Buffalo Inc. (6676), most recently on 2026-05-13. 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 Buffalo Inc. have?

Buffalo Inc. has 24 buy-side and 9 sell-side disclosures on record, covering ¥4.6B ($29.9M) in total reported value, spanning 2021-11-08 to 2026-05-13.

Where does StockDrifts get Buffalo 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.

Buffalo Inc. 6676

Company

株式会社メルコホールデングスBuffalo Inc.

Investors

Buys

Total Value

¥4.6B ($29.9M)

Avg Return

+60.99%

Last Filing

2026-05-13

Buffalo Inc. (6676) has 24 disclosed large-shareholding filings and 9 disclosed disposals on record, filed by 4 distinct investors. Together those filings cover ¥4.6B ($29.9M) in reported transaction value. The earliest filing StockDrifts holds for Buffalo Inc. is dated 2021-11-08; the most recent is 2026-05-13. 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 +60.99%, 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
2026-05-27	BUY	Market Buy	株式会社メルコグループ	strategic	8.4M	¥2,320	+19.3%	¥2.8B ($18.0M)
2026-05-27	BUY	unknown	牧文	activist	85.2K	¥2,320	+19.3%	¥198M ($1.3M)
2026-05-27	SELL	unknown	牧寛之	activist	3.2M	¥2,320	-19.3%	¥2.8B ($18.0M)
2026-05-13	BUY	unknown	株式会社メルコグループ	strategic	7.2M	¥2,568	-8.4%	¥18.6B ($120.0M)
2026-05-13	BUY	Market Buy	牧文	activist	85.2K	¥2,568	-8.4%	¥12M ($80K)
2026-05-13	BUY	Market Buy	牧寛之	activist	4.4M	¥2,568	-8.4%	¥271M ($1.7M)
2026-05-13	BUY	unknown	株式会社メルコグループ	strategic	7.2M	¥2,568	-8.4%	¥18.6B ($120.0M)
2026-05-13	BUY	Market Buy	牧文	activist	85.2K	¥2,568	-8.4%	¥12M ($80K)
2026-05-13	BUY	Market Buy	牧寛之	activist	4.4M	¥2,568	-8.4%	¥271M ($1.7M)
2026-03-24	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	3.6M	¥2,465	+2.7%	¥8.9B ($57.6M)
2026-03-09	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	3.6M	¥2,382.5	+6.2%	¥8.6B ($55.6M)
2026-03-04	BUY	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.1M	¥2,365	+7.0%	¥392M ($2.5M)
2026-03-04	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	3.6M	¥2,365	+7.0%	¥105M ($677K)
2026-02-13	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	3.6M	¥2,710	-6.6%	¥500M ($3.2M)
2025-09-09	SELL	unknown	株式会社メルコグループ MELCO Inc.	strategic	3.6M	¥1,850	-36.8%	¥1.0B ($6.6M)
2025-09-04	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	4.2M	¥1,750	+44.6%	¥1.2B ($7.7M)
2025-08-19	BUY	unknown	牧文 Aya Maki	activist	42.6K	¥1,762.5	+43.6%	¥75M ($484K)
2025-08-19	SELL	unknown	牧寛之 Maki Hiroyuki	activist	2.3M	¥1,762.5	-43.6%	¥262M ($1.7M)
2025-08-19	SELL	unknown	牧寛之 Maki Hiroyuki	activist	2.3M	¥1,762.5	-43.6%	¥262M ($1.7M)
2025-08-19	BUY	unknown	牧文 Aya Maki	activist	42.6K	¥1,762.5	+43.6%	¥75M ($484K)
2025-07-29	BUY	Market Buy	牧文 Aya Maki	activist	42.6K	¥1,148.5	+120.4%	¥7M ($47K)
2025-07-29	BUY	unknown	牧文 Aya Maki	activist	42.6K	¥1,148.5	+120.4%	¥7M ($47K)
2025-07-29	BUY	unknown	牧寛之 Maki Hiroyuki	activist	2.4M	¥1,148.5	+120.4%	¥460M ($3.0M)
2025-07-29	BUY	Market Buy	牧寛之 Maki Hiroyuki	activist	2.4M	¥1,148.5	+120.4%	¥454M ($2.9M)
2025-06-03	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	4.2M	¥1,170.5	+116.2%	¥2.5B ($16.2M)
2025-06-03	SELL	unknown	株式会社メルコグループ MELCO Inc.	strategic	4.2M	¥1,170.5	-116.2%	¥2.5B ($16.2M)
2025-05-14	SELL	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.2M	¥1,083	-133.7%	¥389M ($2.5M)
2025-05-14	BUY	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.6M	¥1,083	+133.7%	¥164M ($1.1M)
2025-03-31	BUY	Market Buy	牧文 Aya Maki	activist	42.6K	¥1,105	+129.1%	¥5M ($33K)
2025-03-31	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	6.3M	¥1,105	+129.1%	¥522M ($3.4M)
2025-03-31	BUY	Market Buy	牧寛之 Maki Hiroyuki	activist	2.4M	¥1,105	+129.1%	¥418M ($2.7M)
2024-09-20	BUY	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.6M	¥1,907.5	+32.7%	¥3.0B ($19.3M)
2024-09-03	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	6.5M	¥1,810	+39.8%	¥11.7B ($75.5M)
2024-07-08	SELL	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	6.5M	¥1,690	-49.8%	¥2.1B ($13.9M)
2024-07-08	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	7.7M	¥1,690	+49.8%	¥13.1B ($84.4M)
2024-07-05	SELL	unknown	株式会社メルコグループ MELCO Inc.	strategic	6.5M	¥1,725	-46.7%	¥2.2B ($14.2M)
2024-07-05	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	6.5M	¥1,725	+46.7%	¥2.2B ($14.2M)
2024-07-04	BUY	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.8M	¥1,735	+45.9%	¥3.1B ($19.9M)
2024-07-04	SELL	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.6M	¥1,735	-45.9%	¥370M ($2.4M)
2024-04-24	BUY	Market Buy	エフィッシモキャピタルマネージメントピーティーイーエルティーディー(Effissimo Capital Management Pte. Ltd.) Effissimo Capital Management Pte. Ltd.	passive	1.8M	¥1,700	+48.9%	¥723M ($4.7M)
2023-11-22	BUY	Market Buy	牧文 Aya Maki	activist	42.6K	¥1,667.5	+51.8%	¥71M ($458K)
2023-11-22	BUY	Market Buy	牧寛之 Maki Hiroyuki	activist	2.3M	¥1,667.5	+51.8%	¥500M ($3.2M)
2023-08-31	BUY	Market Buy	牧文 Aya Maki	activist	42.6K	¥1,605	+57.7%	¥68M ($441K)
2023-08-31	BUY	Market Buy	牧寛之 Maki Hiroyuki	activist	2.0M	¥1,605	+57.7%	¥1.0B ($6.7M)
2023-08-31	SELL	unknown	株式会社メルコグループ MELCO Inc.	strategic	7.7M	¥1,605	-57.7%	¥1.0B ($6.7M)
2023-08-22	BUY	unknown	株式会社メルコグループ MELCO Inc.	strategic	8.4M	¥1,540	+64.3%	¥723M ($4.7M)
2023-08-22	BUY	Market Buy	株式会社メルコグループ MELCO Inc.	strategic	8.4M	¥1,540	+64.3%	¥723M ($4.7M)
2023-06-01	BUY	unknown	牧文 Aya Maki	activist	42.6K	¥1,552.5	+63.0%	¥66M ($427K)
2023-06-01	BUY	unknown	牧寛之 Maki Hiroyuki	activist	1.3M	¥1,552.5	+63.0%	¥2.0B ($13.1M)
2022-05-19	BUY	unknown	株式会社マキス Makis co,.ltd.	strategic	8.4M	¥1,775	+42.6%	¥14.9B ($96.1M)

Showing the 50 most recent of 55 filings.

Frequently asked questions

Who has been buying Buffalo Inc. stock?: 4 distinct investors have filed 24 disclosed large-shareholding filings in Buffalo Inc. (6676), most recently on 2026-05-13. 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 Buffalo Inc. have?: Buffalo Inc. has 24 buy-side and 9 sell-side disclosures on record, covering ¥4.6B ($29.9M) in total reported value, spanning 2021-11-08 to 2026-05-13.
Where does StockDrifts get Buffalo 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 Buffalo Inc.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.