| Summary of options activity |
No new share options granted during the years ended December 31, 2021, 2022 and 2023. A summary of the Company’s equity award activity held by both the Company’s employees and CIH’s employees under the 1999 Plan, 2010 Plan and 2015 Plan for each of the three years ended December 31, 2023 was stated below: | | | | | | | | | | | | | | | Weighted- | | | | | | | Weighted- | | Average | | | | | | | Average per | | Remaining | | Aggregate | Options Granted to Employees | | Number of | | share Exercise | | Contractual | | Intrinsic | and Directors | | Shares | | Price | | Term (years) | | Value | Outstanding, December 31, 2020 | | 6,725,855 | | 3.97 | | 4.84 | | — | Forfeited | | (93,160) | | 2.30 | | | | | Expired | | (363,430) | | 6.70 | | | | | Exercised | | (22,000) | | 5.37 | | | | | Outstanding, December 31, 2021 | | 6,247,265 | | 3.83 | | 6.46 | | — | Vested and expected to vest at December 31, 2021 | | 6,247,265 | | 3.83 | | 6.46 | | — | Exercisable at December 31, 2021 | | 5,792,080 | | 3.97 | | 6.33 | | — |
| | | | | | | | | | | | | | | Weighted- | | | | | | | Weighted- | | Average | | | | | | | Average per | | Remaining | | Aggregate | Options Granted to Employees | | Number of | | share Exercise | | Contractual | | Intrinsic | and Directors | | Shares | | Price | | Term (years) | | Value | Outstanding, December 31, 2021 | | 6,247,265 | | 3.83 | | 6.46 | | — | Forfeited | | (99,620) | | 3.71 | | | | | Expired | | (275,620) | | 3.99 | | | | | Exercised | | (240) | | 6.10 | | | | | Outstanding, December 31, 2022 | | 5,871,785 | | 3.82 | | 5.57 | | — | Vested and expected to vest at December 31, 2022 | | 5,871,785 | | 3.82 | | 5.57 | | — | Exercisable at December 31, 2022 | | 5,637,960 | | 3.86 | | 5.53 | | — |
| | | | | | | | | | | | | | | Weighted- | | | | | | | Weighted- | | Average | | | | | | | Average per | | Remaining | | | | | | | share | | Contractual | | Aggregate | Options Granted to Employees | | Number of | | Exercise | | Term | | Intrinsic | and Directors | | Shares | | Price | | (years) | | Value | Outstanding, December 31, 2022 | | 5,871,785 | | 3.82 | | 5.57 | | — | Forfeited | | (18,980) | | 6.46 | | | | | Expired | | (145,730) | | 5.54 | | | | | Exercised | | — | | — | | | | | Outstanding, December 31, 2023 | | 5,707,075 | | 3.71 | | 5.06 | | — | Vested and expected to vest at December 31, 2023 | | 5,707,075 | | 3.71 | | 5.06 | | — | Exercisable at December 31, 2023 | | 5,707,075 | | 3.71 | | 5.06 | | — |
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