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Dec. 15, 2025 OSE Adjustment and Change on Securities Options (Effective from December 29, 2025)
Stock splits are scheduled for the underlying securities, as listed below. (effective from January 1, 2026)
In accordance with this, OSE shall adjust the strike prices of option contracts which are based upon these underlying securities on December 29, 2025, the date on which trading starts for shares after the stock splits.
| Underlying securities | Code | Strike price*1,2 | Open interest*1 | Number of securities for one delivery unit*1 | Position limits*1(units) | Large position reporting threshold for securities options*1(units) | Hard Block for J-NET Trading*1 |
| IBIDEN CO., LTD. | 4062 | divided by two | multiplied by two | No Change | 14,000→28,100 | 2,800→5,600 | No Change |
| Mitsui Chemicals, Inc. | 4183 | divided by two | multiplied by two | No Change | 20,000→40,100 | 4,000→8,000 | No Change |
| BRIDGESTONE CORPORATION | 5108 | divided by two | multiplied by two | No Change | 71,300→142,700 | 14,200→28,500 | No Change |
| MABUCHI MOTOR CO.,LTD. | 6592 | divided by two | multiplied by two | No Change | 13,000→26,000 | 2,600→5,200 | No Change |
| ITOCHU Corporation | 8001 | divided by five | multiplied by five | No Change | 158,400→792,400 | 31,600→158,400 | No Change |
| Sumitomo Realty & Development Co.,Ltd. | 8830 | divided by two | multiplied by two | No Change | 47,600→93,600 | 9,500→18,700 | No Change |
| SoftBank Group Corp. | 9984 | divided by four | multiplied by four | No Change | 146,900→571,100 | 29,300→114,200 | No Change |
- Strike price, Open interest, Number of securities for one delivery unit, Position limits,Large position reporting threshold for securities options and Hard Block for J-NET Trading compared to December 26, 2025.
- If there are odd lots less than one yen in the strike price, they shall be rounded to the nearest yen(For strike prices of flexible options, odd lots less than the second decimal place shall be rounded to the nearest yen.).
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