本研究評估台灣企業之碳揭露與參與碳抵換專案對企業價值與排放強度的影響。由於台灣碳申報制度與碳抵換專案機制仍處於氣候政策實施的早期階段,具有參與者有限、處理時點交錯，以及受處理企業數量較少等特徵。為了應對這些挑戰,本研究結合『縱橫資料迴歸模型』、『逆機率處理加權（IPTW）』合併『雙重穩健估計方法』,以及『合成控制法（SCM）』來分析此議題。
研究結果顯示,碳揭露在全樣本中與企業價值呈正向關係，但不同產業別之效果存在明顯差異。在修正揭露的選擇偏誤後,正向效果僅在半導體產業中維持顯著,這表示傳統迴歸結果可能受到非隨機揭露決策所影響。其次,參與碳抵換專案整體上與較低的企業價值相關,且在控制參與抵換專案的選擇偏誤後,此負向效果變得更強,顯示傳統估計可能低估了氣候承諾所伴隨的評價成本。最後,參與碳抵換專案在全樣本、半導體及硬體產業中都能降低排放強度,且這些結果在修正選擇偏誤後大致維持不變,此結論可能是因為碳排量除了管理及訊息因素,受到產業特性與碳排技術的影響更大
為了進一步檢驗企業層級的處理效果,本研究針對半導體產業進行SCM分析。結果顯示,參與碳抵換專案通常與排放強度下降相關,特別是在2020年進入該計畫的企業中更為明顯。有趣的是：當我們使用標準的無方向性MSPE率來檢驗處理效應時,所有廠商均無顯著性的處理效應。為此,我們以考慮方向性來修正統計量,而在此單側檢定統計量下,我們發現部分廠商的處理效應的顯著存在。本文最後詳細解說對台積電與聯電的合成控制分析結果。

We evaluate the effects of carbon disclosure and participation in carbon offset projects on firm value and emission intensity in Taiwan. As in the early stage of climate policy implementation, Taiwan’s carbon reporting and offset-project regime was characterized by limited participation, staggered treatment timing, and a small number of treated firms. To address these challenges, we combine panel regression models, doubly robust inverse probability treatment weighting (IPTW) estimators, and synthetic control method (SCM) analyses.
The results show that carbon disclosure is positively associated with firm value in the full sample, although industry-level effects vary considerably. After correcting for selection bias, the positive valuation effect remains significant only in the semiconductor industry, suggesting that some baseline findings were driven by non-random disclosure decisions. Participation in carbon offset projects is generally associated with lower firm value, and this negative effect becomes stronger after accounting for selection into participation, indicating that conventional estimates understate the valuation costs of climate commitments. In contrast, participation is associated with lower emission intensity in the full sample, semiconductor, and hardware industries, and these results remain largely unchanged after selection correction. IPTW does not change the results probably because apart from financial aspects, emission is more affected by industry characteristics and dicarbon technologies.
To further examine firm-level treatment effects, we apply SCM to the semiconductor industry. The results indicate that participation in carbon offset projects is generally associated with reductions in emission intensity. However, we find that when using the standard non-directing MSPE ratio to test the treatment effect, none of the treated firms exhibit statistically significant effects. We propose a modification on the statistics by considering directions, and the one-sided test statistics (negative) provide strong evidence for the treatment effects. Finally, we provide detailed SCM analyses for TSMC and UMC.

Abadie, A. (2021). Using synthetic controls: Feasibility, data requirements, and methodological aspects. Journal of Economic Literature, 59(2), 391–425.
Abadie, A., Diamond, A., & Hainmueller, J. (2010). Synthetic control methods for comparative case studies: Estimating the effect of California’s tobacco control program. Journal of the American Statistical Association, 105(490), 493–505.
Abadie, A., Diamond, A., & Hainmueller, J. (2015). Comparative politics and the synthetic control method. American Journal of Political Science, 59(2), 495–510.
Badgley, G., Freeman, J., Hamman, J. J., Haya, B., Trugman, A. T., Anderegg, W. R., & Cullenward, D. (2022). Systematic over-crediting in California’s forest carbon offsets program. Global Change Biology, 28(4), 1433–1445.
Barth, M. E., & McNichols, M. F. (1994). Estimation and market valuation of environmental liabilities relating to Superfund sites. Journal of Accounting Research, 32, 177–209.
Bolton, P., & Kacperczyk, M. (2021). Do investors care about carbon risk? Journal of Financial Economics, 142(2), 517–549.
Campbell, K., Sefcik, S. E., & Soderstrom, N. S. (2003). Site uncertainty, allocation uncertainty, and Superfund liability valuation. Journal of Accounting and Public Policy, 22(6), 459–487.
Chua, Y. H., & She, L. (2025). Do investors care about carbon offsets? SSRN working paper.
Clark, G. L., Feiner, A., & Viehs, M. (2015). From the stockholder to the stakeholder: How sustainability can drive financial outperformance. SSRN.
Clarkson, P. M., Li, Y., Richardson, G. D., & Vasvari, F. P. (2011). Does it really pay to be green? Determinants and consequences of proactive environmental strategies. Journal of Accounting and Public Policy, 30(2), 122–144.
Colmer, J., Martin, R., Muûls, M., & Wagner, U. J. (2025). Does pricing carbon mitigate climate change? Firm-level evidence from the European Union Emissions Trading System. The Review of Economic Studies, 92(3), 1625–1660.
Dechezleprêtre, A., Nachtigall, D., & Venmans, F. (2023). The joint impact of the European Union emissions trading system on carbon emissions and economic performance. Journal of Environmental Economics and Management, 118, 102758.
Delmas, M. A., & Burbano, V. C. (2011). The drivers of greenwashing. California Management Review, 54(1), 64–87.
Delmas, M. A., Nairn-Birch, N., & Lim, J. (2015). Dynamics of environmental and financial performance: The case of greenhouse gas emissions. Organization & Environment, 28(4), 374–393.
Dhaliwal, D. S., Li, O. Z., Tsang, A., & Yang, Y. G. (2011). Voluntary nonfinancial disclosure and the cost of equity capital: The initiation of corporate social responsibility reporting. The Accounting Review, 86(1), 59–100.
Downar, B., Ernstberger, J., Reichelstein, S., Schwenen, S., & Zaklan, A. (2021). The impact of carbon disclosure mandates on emissions and financial operating performance. Review of Accounting Studies, 26, 1137–1175.
Fiechter, P., Hitz, J.-M., & Lehmann, N. (2022). Real effects of a widespread CSR reporting mandate: Evidence from the European Union’s CSR Directive. Journal of Accounting Research, 60(4), 1499–1549.
Firpo, S., & Possebom, V. (2018). Synthetic control method: Inference, sensitivity analysis and confidence sets. Journal of Causal Inference, 6(2), 20160026.
Flammer, C. (2013). Corporate social responsibility and shareholder reaction: The environmental awareness of investors. Academy of Management Journal, 56(3), 758–781.
Flammer, C. (2021). Corporate green bonds. Journal of Financial Economics, 142(2), 499–516.
Funk, M. J., Westreich, D., Wiesen, C., Stürmer, T., Brookhart, M. A., & Davidian, M. (2011).
Doubly robust estimation of causal effects. American journal of epidemiology, 173(7), 761-767.
Garzón-Jiménez, R., & Zorio-Grima, A. (2021). Effects of carbon emissions, environmental disclosures and CSR assurance on cost of equity in emerging markets. Sustainability, 13(2), 696.
Grewal, J., Riedl, E. J., & Serafeim, G. (2019). Market reaction to mandatory nonfinancial disclosure. Management Science, 65(7), 3061–3084.
Griffin, P. A., Lont, D. H., & Sun, E. Y. (2017). The relevance to investors of greenhouse gas emission disclosures. Contemporary Accounting Research, 34(2), 1265–1297.
Hardiyansah, M., Agustini, A. T., & Purnamawati, I. (2021). The effect of carbon emission disclosure on firm value: Environmental performance and industrial type. The Journal of Asian Finance, Economics and Business, 8(1), 123–133.
Hart, S. L. (1995). A natural-resource-based view of the firm. Academy of Management Review, 20(4), 986–1014.
Hart, S. L., & Ahuja, G. (1996). Does it pay to be green? An empirical examination of the relationship between emission reduction and firm performance. Business Strategy and the Environment, 5(1), 30–37.
Healy, P. M., & Palepu, K. G. (2001). Information asymmetry, corporate disclosure, and the capital markets: A review of the empirical disclosure literature. Journal of Accounting and Economics, 31(1–3), 405–440.
Heckman, J. J. (1979). Sample selection bias as a specification error. Econometrica, 47(1), 153–161.
Jacobs, B. W., Singhal, V. R., & Subramanian, R. (2010). An empirical investigation of environmental performance and the market value of the firm. Journal of Operations Management, 28(5), 430–441.
Jiang, Y., Luo, L., Xu, J., & Shao, X. (2021). The value relevance of corporate voluntary carbon disclosure: Evidence from the United States and BRIC countries. Journal of Contemporary Accounting & Economics, 17(3), 100279.
Khan, M., Serafeim, G., & Yoon, A. (2016). Corporate sustainability: First evidence on materiality. The Accounting Review, 91(6), 1697–1724.
Kim, S., Li, T., & Wu, Y. (2025). Carbon offsets: Decarbonization or transition-washing? European Corporate Governance Institute–Finance Working Paper No. 1122.
Koenker, R., & Bassett Jr, G. (1978). Regression quantiles. Econometrica: journal of the Econometric Society, 33-50.
Koenker, R., & Hallock, K. F. (2001). Quantile regression. Journal of economic perspectives, 15(4), 143-156.
Lee, J.-H., & Cho, J.-H. (2021). Firm-value effects of carbon emissions and carbon disclosures—Evidence from Korea. International Journal of Environmental Research and Public Health, 18(22), 12166.
Little, R. J. A., & Rubin, D. B. (2019). Statistical analysis with missing data (3rd ed.). Wiley.
Luo, L., & Tang, Q. (2014). Does voluntary carbon disclosure reflect underlying carbon performance? Journal of Contemporary Accounting & Economics, 10(3), 191–205.
Margolis, J. D., Elfenbein, H. A., & Walsh, J. P. (2007). Does it pay to be good? A meta-analysis and redirection of research on the relationship between corporate social and financial performance. Ann Arbor, 1001(48109-1234), 1-68.
Matsumura, E. M., Prakash, R., & Vera-Muñoz, S. C. (2014). Firm-value effects of carbon emissions and carbon disclosures. The Accounting Review, 89(2), 695–724.
Perdichizzi, S., Buchetti, B., Cicchiello, A. F., & Dal Maso, L. (2024). Carbon emission and firms’ value: Evidence from Europe. Energy Economics, 131, 107324.
Plumlee, M., Brown, D., Hayes, R. M., & Marshall, R. S. (2015). Voluntary environmental disclosure quality and firm value: Further evidence. Journal of Accounting and Public Policy, 34(4), 336–361.
Probst, B. S., Toetzke, M., Kontoleon, A., Díaz Anadón, L., Minx, J. C., Haya, B. K., Schneider, L., Trotter, P. A., West, T. A. P., Kachi, A., & Hoffmann, V. H. (2024). Systematic assessment of the achieved emission reductions of carbon crediting projects. Nature Communications, 15, 9562.
Ruseva, T., Hedrick, J., Marland, G., Tovar, H., Sabou, C., & Besombes, E. (2017). Rethinking standards of permanence, additionality, and leakage for forest carbon offsets. Journal of Environmental Management, 203, 1104–1113.
Saka, C., & Oshika, T. (2014). Disclosure effects, carbon emissions and corporate value. Sustainability Accounting, Management and Policy Journal, 5(1), 22–45.
Stanny, E. (2013). Voluntary disclosures of emissions by US firms. Business Strategy and the Environment, 22(3), 145–158.
Stanny, E., & Ely, K. (2008). Corporate environmental disclosures about the effects of climate change. Corporate Social Responsibility and Environmental Management, 15(6), 338–348.
Stapp, J. R., Nolte, C., Potts, M. D., Baumann, M., & Butsic, V. (2023). Little evidence of management change in California’s forest offset program. Communications Earth & Environment, 4, 331.
Tang, D. Y., & Zhang, Y. (2020). Do shareholders benefit from green bonds? Journal of Corporate Finance, 61, 101427.
Trencher, G., Nick, S., Carlson, J., & Johnson, M. (2024). Demand for low-quality offsets by major companies undermines climate integrity of the voluntary carbon market. Nature Communications, 15, 6863.
Verrecchia, R. E. (1983). Discretionary disclosure. Journal of Accounting and Economics, 5, 179–194.
West, T. A. P., Börner, J., Sills, E. O., & Kontoleon, A. (2020). Overstated carbon emission reductions from voluntary REDD+ projects in the Brazilian Amazon. Proceedings of the National Academy of Sciences, 117(39), 24188–24194.
West, T. A. P., Wunder, S., Sills, E. O., Börner, J., Rifai, S. W., Neidermeier, A. N., Frey, G. P., & Kontoleon, A. (2023). Action needed to make carbon offsets from forest conservation work for climate change mitigation. Science, 381(6660), 873–877.
賴宗志. (2024). 縣市生育津貼對生育率的直接與間接效果: 中介分析合成控制法的應用. 經濟論文叢刊, 52(2), 197-227.