Who has been buying Sumitomo Riko Company Limited stock?

7 distinct investors have filed 3 disclosed large-shareholding filings in Sumitomo Riko Company Limited (5191), most recently on 2026-01-19. 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 Sumitomo Riko Company Limited have?

Sumitomo Riko Company Limited has 3 buy-side and 7 sell-side disclosures on record, covering ¥526.1B ($3.4B) in total reported value, spanning 2024-08-09 to 2026-01-19.

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.

Sumitomo Riko Company Limited 5191

Company

住友理工株式会社Sumitomo Riko Company Limited

Investors

Buys

Total Value

¥526.1B ($3.4B)

Avg Return

+33.60%

Last Filing

2026-01-19

Sumitomo Riko Company Limited (5191) has 3 disclosed large-shareholding filings and 7 disclosed disposals on record, filed by 7 distinct investors. Together those filings cover ¥526.1B ($3.4B) in reported transaction value. The earliest filing StockDrifts holds for Sumitomo Riko Company Limited is dated 2024-08-09; the most recent is 2026-01-19. Across these filings the average return since disclosure is +33.60%, 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
2026-01-19	BUY	acquisition	住友電気工業株式会社	activist	103.8M	¥2,592	+0.1%	¥23.2B ($150.0M)
2026-01-19	SELL	acquisition	株式会社アライドマテリアル	other	0	¥2,592	-0.1%	¥539M ($3.5M)
2026-01-19	SELL	acquisition	九州住電精密株式会社	other	0	¥2,592	-0.1%	¥485M ($3.1M)
2026-01-19	SELL	acquisition	住友電工焼結合金株式会社	other	0	¥2,592	-0.1%	¥485M ($3.1M)
2026-01-19	SELL	acquisition	日新電機株式会社	other	0	¥2,592	-0.1%	¥351M ($2.3M)
2025-12-23	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	unknown	0	¥2,589	-	-
2025-12-22	BUY	acquisition	住友電工焼結合金株式会社	strategic	184.9K	¥2,587	-	-
2025-12-22	BUY	acquisition	住友電気工業株式会社	activist	94.9M	¥2,587	+0.3%	¥113.7B ($733.3M)
2025-12-22	BUY	acquisition	株式会社アライドマテリアル	strategic	206.7K	¥2,587	-	-
2025-12-22	BUY	acquisition	九州住電精密株式会社	strategic	184.9K	¥2,587	-	-
2025-12-22	SELL	acquisition	住電商事株式会社	unknown	0	¥2,587	-0.3%	¥296M ($1.9M)
2025-12-22	BUY	acquisition	日新電機株式会社	strategic	138.2K	¥2,587	-	¥357M ($2.3M)
2025-04-24	SELL	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	strategic	8.9M	¥1,547	-67.7%	¥1.2B ($7.8M)
2025-04-11	SELL	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES.CO.,LTD.	strategic	9.7M	¥1,360	-90.7%	¥1.5B ($9.8M)
2025-03-24	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD	strategic	9.2M	¥1,868	-	¥17.2B ($110.9M)
2025-03-24	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD	strategic	9.2M	¥1,868	-	¥17.2B ($110.9M)
2024-08-09	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	strategic	10.8M	¥1,294	-	¥14.0B ($90.2M)
2024-08-09	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	strategic	10.8M	¥1,294	-	¥1.6B ($10.5M)
2024-08-09	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	strategic	8.3M	¥1,294	-	¥10.7B ($69.2M)
2024-08-09	BUY	unknown	マルヤス工業株式会社 MARUYASU INDUSTRIES CO.,LTD.	strategic	8.3M	¥1,294	+100.5%	¥10.7B ($69.2M)

Frequently asked questions

Who has been buying Sumitomo Riko Company Limited stock?: 7 distinct investors have filed 3 disclosed large-shareholding filings in Sumitomo Riko Company Limited (5191), most recently on 2026-01-19. 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 Sumitomo Riko Company Limited have?: Sumitomo Riko Company Limited has 3 buy-side and 7 sell-side disclosures on record, covering ¥526.1B ($3.4B) in total reported value, spanning 2024-08-09 to 2026-01-19.
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.