|
| 2017 | 2018 | total |
| Initial Sample (A-share of listed company of SSE) | 895 | 895 | 1790 |
| ExExculude: Financial listed companies | 36 | 36 | 72 |
| Companies with missing data | 59 | 59 | 118 |
| ST, *ST companies | 75 | 75 | 150 |
| Final valid sample | 725 | 725 | 1450 |