Who has been buying sinops Inc. stock?

6 distinct investors have filed 5 disclosed large-shareholding filings in sinops Inc. (4428), most recently on 2025-09-22. 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 sinops Inc. have?

sinops Inc. has 5 buy-side and 20 sell-side disclosures on record, covering ¥574M ($3.7M) in total reported value, spanning 2021-03-30 to 2025-09-22.

Where does StockDrifts get sinops 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.

sinops Inc. 4428

Company

株式会社シノプスsinops Inc.

Investors

Buys

Total Value

¥574M ($3.7M)

Avg Return

-41.34%

Last Filing

2025-09-22

sinops Inc. (4428) has 5 disclosed large-shareholding filings and 20 disclosed disposals on record, filed by 6 distinct investors. Together those filings cover ¥574M ($3.7M) in reported transaction value. The earliest filing StockDrifts holds for sinops Inc. is dated 2021-03-30; the most recent is 2025-09-22. 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 -41.34%, 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
2026-05-28	BUY	unknown	南谷清江	strategic	153.0K	¥630	-0.8%	¥96M ($622K)
2026-05-28	BUY	Market Buy	南谷洋志	strategic	134.8K	¥630	-0.8%	¥4M ($28K)
2026-05-28	BUY	unknown	合同会社南谷ホールディングス	strategic	2.1M	¥630	-0.8%	¥1.3B ($8.6M)
2026-05-28	BUY	Market Buy	南谷洋志	strategic	131.1K	¥630	-0.8%	¥2M ($13K)
2026-05-28	BUY	unknown	合同会社南谷ホールディングス	strategic	2.1M	¥630	-0.8%	¥1.3B ($8.6M)
2025-09-22	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥978	-29.6%	¥150M ($965K)
2025-09-22	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥978	-29.6%	¥125M ($806K)
2025-09-22	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥978	-29.6%	¥150M ($965K)
2025-09-22	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥978	-29.6%	¥125M ($806K)
2025-09-22	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥978	-29.6%	¥2.1B ($13.3M)
2025-09-22	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥978	-29.6%	¥2.1B ($13.3M)
2025-07-07	SELL	unknown	みずほ証券株式会社 Mizuho Securities Co., Ltd.	unknown	0	¥863	+20.2%	¥391M ($2.5M)
2025-03-31	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥838	-17.8%	¥128M ($827K)
2025-03-31	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥838	-17.8%	¥107M ($691K)
2025-03-31	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥838	-17.8%	¥128M ($827K)
2025-03-31	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥838	-17.8%	¥107M ($691K)
2025-03-31	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥838	-17.8%	¥1.8B ($11.4M)
2025-03-31	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥838	-17.8%	¥1.8B ($11.4M)
2025-01-06	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥768	-10.3%	¥118M ($758K)
2025-01-06	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥768	-10.3%	¥98M ($633K)
2025-01-06	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥768	-10.3%	¥1.6B ($10.4M)
2024-09-30	SELL	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥999	+31.0%	¥625K ($4K)
2024-09-30	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥999	-31.0%	¥128M ($824K)
2024-09-30	SELL	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥999	+31.0%	¥3M ($20K)
2024-07-02	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥1,210	-43.1%	¥185M ($1.2M)
2024-07-02	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	127.8K	¥1,210	-43.1%	¥2M ($15K)
2024-07-02	SELL	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥1,210	+43.1%	¥756K ($5K)
2024-04-01	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥1,377	-50.0%	¥211M ($1.4M)
2024-04-01	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	125.4K	¥1,377	-50.0%	¥173M ($1.1M)
2024-04-01	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥1,377	-50.0%	¥2.9B ($18.7M)
2024-02-29	SELL	unknown	南谷清江 Kiyoe Minamiya	strategic	153.0K	¥1,468	+53.1%	¥98M ($633K)
2024-02-29	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	125.4K	¥1,468	-53.1%	¥184M ($1.2M)
2024-02-29	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥1,468	-53.1%	¥3.1B ($19.9M)
2023-12-28	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥983	-29.9%	¥216M ($1.4M)
2023-12-28	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	125.4K	¥983	-29.9%	¥123M ($795K)
2023-12-28	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥983	-29.9%	¥2.1B ($13.3M)
2023-10-04	SELL	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥880	+21.7%	¥4M ($25K)
2023-10-04	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	125.4K	¥880	-21.7%	¥110M ($712K)
2023-10-04	SELL	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥880	+21.7%	¥550K ($4K)
2023-07-05	SELL	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥992	+30.5%	¥5M ($32K)
2023-07-05	SELL	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥992	+30.5%	¥619K ($4K)
2023-07-05	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	125.4K	¥992	-30.5%	¥3M ($20K)
2023-03-30	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥1,008	-31.6%	¥222M ($1.4M)
2023-03-30	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	122.2K	¥1,008	-31.6%	¥123M ($794K)
2023-03-30	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥1,008	-31.6%	¥222M ($1.4M)
2023-03-30	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	122.2K	¥1,008	-31.6%	¥123M ($794K)
2023-03-30	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥1,008	-31.6%	¥2.1B ($13.7M)
2023-03-30	BUY	unknown	合同会社南谷ホールディングス Minamitani holdings	strategic	2.1M	¥1,008	-31.6%	¥2.1B ($13.7M)
2023-02-27	BUY	unknown	南谷清江 Kiyoe Minamiya	strategic	220.0K	¥1,005	-31.4%	¥221M ($1.4M)
2023-02-27	BUY	unknown	南谷洋志 Hiroshi Minamitani	strategic	122.2K	¥1,005	-31.4%	¥123M ($792K)

Showing the 50 most recent of 74 filings.

Frequently asked questions

Who has been buying sinops Inc. stock?: 6 distinct investors have filed 5 disclosed large-shareholding filings in sinops Inc. (4428), most recently on 2025-09-22. 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 sinops Inc. have?: sinops Inc. has 5 buy-side and 20 sell-side disclosures on record, covering ¥574M ($3.7M) in total reported value, spanning 2021-03-30 to 2025-09-22.
Where does StockDrifts get sinops 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 sinops Inc.. For how StockDrifts scores these disclosures, see the Japan insider signal tier research, or browse every Japanese stock we track.