StockDriftsStockDriftsSEIKOH GIKEN Co., Ltd. (6834) has 8 disclosed large-shareholding filings and 16 disclosed disposals on record, filed by 11 distinct investors. Together those filings cover ¥5.1B ($32.6M) in reported transaction value. The earliest filing StockDrifts holds for SEIKOH GIKEN Co., Ltd. is dated 2021-12-02; the most recent is 2025-10-09. Across these filings the average return since disclosure is +829.92%, measured from each filing date to the latest available close.
| Date | Type | Source | Insider | Purpose | Shares | Price at filing | Return | Value |
|---|---|---|---|---|---|---|---|---|
| 2026-09-01 | BUY | negotiated | 細江由紀子 | activist | 282.5K | ¥5,630 | - | - |
| 2026-09-01 | BUY | negotiated | 有限会社 光研 | activist | 583.5K | ¥5,630 | - | - |
| 2025-10-09 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥10,170 | - | - |
| 2025-10-09 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥10,170 | - | - |
| 2025-10-09 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥10,170 | - | - |
| 2025-10-09 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥10,170 | - | - |
| 2025-10-06 | BUY | Market Buy | 野村アセットマネジメント株式会社 Nomura Asset Management Co., Ltd. | other | 546.8K | ¥9,630 | -39.3% | ¥422M ($2.7M) |
| 2025-10-06 | BUY | Market Buy | 野村證券株式会社 Nomura Securities Co.,Ltd. | other | 70.5K | ¥9,630 | -39.3% | ¥530M ($3.4M) |
| 2025-10-06 | BUY | Market Buy | ノムラ インターナショナル ピーエルシー NOMURA INTERNATIONAL PLC | other | 2.9K | ¥9,630 | - | ¥28M ($180K) |
| 2025-09-09 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥8,410 | - | - |
| 2025-09-09 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥8,410 | - | - |
| 2025-09-09 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥8,410 | - | - |
| 2025-09-09 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥8,410 | - | - |
| 2025-09-09 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥8,410 | - | - |
| 2025-09-09 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥8,410 | - | - |
| 2025-02-07 | BUY | negotiated | 細江宣明 Nobuaki Hosoe | activist | 80.7K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 細江宣明 Nobuaki Hosoe | activist | 80.7K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 890.5K | ¥5,060 | - | - |
| 2025-02-07 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 460.5K | ¥5,060 | -15.6% | ¥1.1B ($7.0M) |
| 2025-02-07 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 675.5K | ¥5,060 | -15.6% | ¥1.1B ($7.0M) |
| 2025-02-07 | BUY | negotiated | 細江 由紀子 Yukiko Hosoe | activist | 882.5K | ¥5,060 | - | - |
| 2025-02-07 | BUY | Market Buy | 細江由紀子 Yukiko Hosoe | activist | 1.2M | ¥5,060 | +15.6% | ¥1.7B ($10.7M) |
| 2025-02-07 | BUY | negotiated | 細江由紀子 Yukiko Hosoe | activist | 882.5K | ¥5,060 | - | - |
| 2025-02-07 | SELL | negotiated | 細江由紀子 Yukiko Hosoe | activist | 960.5K | ¥5,060 | -15.6% | ¥1.3B ($8.1M) |
| 2025-02-07 | SELL | negotiated | 細江由紀子 Yukiko Hosoe | activist | 681.5K | ¥5,060 | -15.6% | ¥1.4B ($9.1M) |
| 2025-02-07 | BUY | negotiated | 都丸由美子 Yumiko Tomaru | activist | 890.5K | ¥5,060 | - | - |
| 2025-02-07 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 460.5K | ¥5,060 | -15.6% | ¥1.1B ($7.0M) |
| 2025-02-07 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 675.5K | ¥5,060 | -15.6% | ¥1.1B ($7.0M) |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 都丸 沙希 Saki Tomaru | activist | 215.0K | ¥5,060 | - | ¥1.1B ($7.0M) |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社 光研 Kouken Co., Ltd. | activist | 654.5K | ¥5,060 | +15.6% | ¥302M ($2.0M) |
| 2025-02-07 | BUY | negotiated | 有限会社 光研 Kouken Co., Ltd. | activist | 594.5K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社 光研 Kouken Co., Ltd. | activist | 623.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | Market Buy | 有限会社 光研 Kouken Co., Ltd. | activist | 623.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社光研 Kouken Co., Ltd. | activist | 623.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 都丸 沙希 Saki Tomaru | activist | 215.0K | ¥5,060 | - | ¥1.1B ($7.0M) |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2025-02-07 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 694.0K | ¥5,060 | - | - |
| 2024-12-20 | SELL | negotiated | 細江由紀子 Yukiko Hosoe | activist | 282.5K | ¥5,800 | -0.9% | ¥866M ($5.6M) |
| 2024-12-20 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥5,800 | -0.9% | ¥579M ($3.7M) |
| 2024-12-20 | BUY | negotiated | 有限会社 光研 Kouken Co., Ltd. | activist | 583.5K | ¥5,800 | - | - |
| 2024-12-20 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥5,800 | - | - |
| 2024-12-20 | BUY | negotiated | 有限会社 高志 Takashi Co., Ltd. | activist | 654.4K | ¥5,800 | - | - |
| 2024-12-20 | BUY | negotiated | 有限会社 光研 Kouken Co., Ltd. | activist | 583.5K | ¥5,800 | - | - |
| 2024-12-20 | SELL | negotiated | 都丸由美子 Yumiko Tomaru | activist | 330.5K | ¥5,800 | -0.9% | ¥579M ($3.7M) |
| 2024-12-20 | SELL | negotiated | 細江由紀子 Yukiko Hosoe | activist | 282.5K | ¥5,800 | -0.9% | ¥866M ($5.6M) |
| 2024-12-11 | BUY | negotiated | 細江由紀子 Yukiko Hosoe | activist | 432.5K | ¥5,000 | - | - |
Showing the 50 most recent of 75 filings.
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.