Who has been buying STG Co., Ltd. stock?

9 distinct investors have filed 10 disclosed large-shareholding filings in STG Co., Ltd. (5858), most recently on 2026-05-12. 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 STG Co., Ltd. have?

STG Co., Ltd. has 10 buy-side and 11 sell-side disclosures on record, covering ¥948M ($6.1M) in total reported value, spanning 2022-03-17 to 2026-05-12.

Where does StockDrifts get STG Co., Ltd. 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.

STG Co., Ltd. 5858

Company

株式会社STGSTG Co., Ltd.

Investors

Buys

Total Value

¥948M ($6.1M)

Avg Return

+31.74%

Last Filing

2026-05-12

STG Co., Ltd. (5858) has 10 disclosed large-shareholding filings and 11 disclosed disposals on record, filed by 9 distinct investors. Together those filings cover ¥948M ($6.1M) in reported transaction value. The earliest filing StockDrifts holds for STG Co., Ltd. is dated 2022-03-17; the most recent is 2026-05-12. 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 +31.74%, 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
2026-05-12	BUY	subscription	株式会社日本政策投資銀行 Development Bank of Japan Inc.	passive	210.5K	¥1,478	-23.1%	¥311M ($2.0M)
2024-12-20	SELL	Market Buy	レオス・キャピタルワークス株式会社 RHEOS CAPITAL WORKS Inc.	passive	45.0K	¥1,197	-24.1%	¥14M ($89K)
2024-12-03	BUY	unknown	株式会社三輝 SANKI CO.,LTD	activist	150.0K	¥1,369	+8.5%	¥205M ($1.3M)
2024-10-18	SELL	unknown	佐藤武幸 SATO TAKEYUKI	strategic	17.8K	¥922	-61.1%	¥49M ($316K)
2024-10-01	BUY	unknown	株式会社三輝 SANKI CO.,LTD	activist	150.0K	¥891.5	+66.6%	¥134M ($863K)
2024-10-01	BUY	unknown	佐藤武幸 SATO TAKEYUKI	strategic	17.8K	¥891.5	+66.6%	¥47M ($306K)
2024-10-01	BUY	unknown	佐藤輝明 SATO TERUAKI	activist	160.0K	¥891.5	+66.6%	¥99M ($638K)
2024-10-01	BUY	unknown	佐藤輝明 SATO TERUAKI	activist	160.0K	¥891.5	+66.6%	¥99M ($638K)
2024-10-01	BUY	unknown	佐藤武幸 SATO TAKEYUKI	strategic	17.8K	¥891.5	+66.6%	¥47M ($306K)
2024-10-01	BUY	unknown	株式会社三輝 SANKI CO.,LTD	activist	150.0K	¥891.5	+66.6%	¥134M ($863K)
2024-08-07	BUY	Market Buy	レオス・キャピタルワークス株式会社 RHEOS CAPITAL WORKS Inc.	passive	56.5K	¥875	+69.7%	¥49M ($319K)
2024-05-15	BUY	unknown	佐藤武幸 SATO TAKEYUKI	strategic	67.8K	¥1,025.5	+44.8%	¥70M ($449K)
2024-05-15	BUY	unknown	佐藤輝明 SATO TERUAKI	activist	260.0K	¥1,025.5	+44.8%	¥267M ($1.7M)
2024-03-28	SELL	unknown	佐藤武幸 SATO TAKEYUKI	strategic	67.8K	¥1,191.5	-24.6%	¥28M ($184K)
2024-03-28	SELL	unknown	佐藤輝明 SATO TERUAKI	activist	260.0K	¥1,191.5	-24.6%	¥74M ($476K)
2024-03-28	BUY	unknown	佐藤武幸 SATO TAKEYUKI	strategic	67.8K	¥1,191.5	+24.6%	¥28M ($184K)
2024-03-28	SELL	unknown	森田泰成 MORITA YASUNARI	activist	34.0K	¥1,191.5	-24.6%	¥21M ($135K)
2024-03-28	BUY	unknown	佐藤輝明 SATO TERUAKI	activist	260.0K	¥1,191.5	+24.6%	¥74M ($476K)
2024-03-27	SELL	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	94.3K	¥1,250.5	-18.8%	¥58M ($374K)
2024-03-27	SELL	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	37.5K	¥1,250.5	-18.8%	¥71M ($459K)
2024-03-25	SELL	Market Buy	三菱UFJキャピタル株式会社 Mitsubishi UFJ Capital Co., Ltd.	passive	40.0K	¥1,590	+6.6%	¥68M ($436K)
2024-03-22	BUY	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	119.3K	¥1,630	-8.9%	¥194M ($1.3M)
2024-03-22	BUY	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	119.3K	¥1,630	-8.9%	¥194M ($1.3M)
2024-03-19	BUY	unknown	佐藤輝明 SATO TERUAKI	activist	274.0K	¥1,625	-8.6%	¥445M ($2.9M)
2024-02-28	BUY	unknown	森田泰成 MORITA YASUNARI	activist	44.0K	¥1,625	-8.6%	¥72M ($461K)
2024-02-28	SELL	unknown	佐藤武幸 SATO TAKEYUKI	strategic	77.8K	¥1,625	+8.6%	¥9M ($59K)
2024-02-28	BUY	Market Buy	佐藤輝明 SATO TERUAKI	activist	274.0K	¥1,625	-8.6%	¥11M ($71K)
2024-02-28	BUY	unknown	森田泰成 MORITA YASUNARI	activist	44.0K	¥1,625	-8.6%	¥72M ($461K)
2024-02-26	BUY	Market Buy	三菱UFJキャピタル株式会社 Mitsubishi UFJ Capital Co., Ltd.	passive	70.0K	¥1,625	-8.6%	¥114M ($734K)
2024-02-22	BUY	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	119.3K	¥1,625	-8.6%	¥194M ($1.3M)
2024-02-22	BUY	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	119.3K	¥1,625	-8.6%	¥194M ($1.3M)
2024-02-22	BUY	Market Buy	株式会社TNPオンザロード TNP On The Road Corporation	passive	119.3K	¥1,625	-8.6%	¥194M ($1.3M)
2022-03-25	SELL	unknown	三菱UFJキャピタル株式会社 (組合名)三菱UFJキャピタル3号投資事業有限責任組合 Mitsubishi UFJ Capital Co., Ltd.	unknown	0	¥1,625	+8.6%	¥114M ($734K)
2022-03-24	BUY	Market Buy	三菱UFJキャピタル株式会社 Mitsubishi UFJ Capital Co., Ltd.	passive	70.0K	¥1,625	-8.6%	¥114M ($734K)
2022-03-18	BUY	Market Buy	株式会社ケイエスピー KSP, Inc.	passive	59.1K	¥1,625	-8.6%	¥18M ($113K)
2022-03-17	SELL	Market Buy	株式会社ケイエスピー KSP, Inc.	passive	59.1K	¥1,625	+8.6%	¥18M ($113K)

Frequently asked questions

Who has been buying STG Co., Ltd. stock?: 9 distinct investors have filed 10 disclosed large-shareholding filings in STG Co., Ltd. (5858), most recently on 2026-05-12. 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 STG Co., Ltd. have?: STG Co., Ltd. has 10 buy-side and 11 sell-side disclosures on record, covering ¥948M ($6.1M) in total reported value, spanning 2022-03-17 to 2026-05-12.
Where does StockDrifts get STG Co., Ltd. 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 STG Co., Ltd.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.