*7.2. Limitations*

The boundary of the Porter hypothesis in this paper assumes that all industries should increase the same level of TFP growth to meet the economic neutrality goals, and it is not the real case. However, we cannot know the actual change value of TFP in different industries under the carbon neutrality target. Therefore, we need to understand this boundary as the average boundary of additional TFP increases in the total society.

Another potential bias of this paper is that the model does not consider the cost of technological progress. Although the proportion of R&D investment in the total social cost is low, it may increase under carbon neutrality. Therefore, technological progress is not free. This paper has no appropriate reference to describe the cost of technological progress. Thus, the paper may underestimate the boundaries of strong Porter's hypothesis to some extent.

**Author Contributions:** Conceptualization, S.H. and Z.J.; methodology, Z.J.; formal analysis, C.D., X.J. and D.Z.; investigation, Y.W.; data curation, S.W.; writing—original draft preparation, S.H. and S.W.; writing—review and editing, Z.C.; visualization, S.W.; supervision, Z.J.; funding acquisition, S.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received support by the provincial management industrial unit of State Grid Zhejiang Electric Power Co., Ltd. (HC-SJ-F01-2022337-BY), the Ministry of Education of China (No. 22YJC790047), the Fundamental Research Funds for the Central Universities (Humanities and Social Sciences) (No. SK2022026), and the Shaanxi Federation of Social Sciences (No. 2022ND0312).

**Data Availability Statement:** The data available are in a publicly accessible repository that does not issue DOIs.

**Conflicts of Interest:** The authors declare no conflict of interest.
