Published 2026-03-25
Keywords
- Green Finance, Quantile-on-Quantile Regression, Green Bond, Wavelet Analysis, Quantile -on-Quantile Causality
- Yeşil Finans, Kantil-Kantil Regresyon, Yeşil Tahvil, Wavelet Analizi, Kantil-Kantil Nedensellik
How to Cite
Copyright (c) 2026 Aslan Aydoğdu

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
How to Cite
Abstract
This study examines the impact of climate policy uncertainty (CPU) on green bond returns (GB) under different time horizons and market conditions. For this purpose, monthly data from the news-based CPU index developed by Gavriilidis (2021) and the S&P Green Bond Index for the period from June 2015 to June 2025 are employed. The analysis is conducted using wavelet-based quantile-on-quantile regression (WQQR) and wavelet-based quantile-on-quantile Granger causality (WQQGC), which capture non-linear, asymmetric, and distribution-dependent dynamics. The findings reveal that the impact of CPU on green bond returns varies across time horizons and quantile levels. In the short term, increases in CPU are found to suppress green bond returns in low-return regimes, while exerting a positive effect in high-return regimes. In the medium term, this relationship reverses, and the CPU effect gradually evolves from negative to positive. In the long term, CPU is found to exert a statistically significant and positive effect on green bond returns across all quantile levels. Furthermore, the causality analysis indicates that the effects of CPU on the green bond market exhibit a heterogeneous, market-condition-dependent structure across both time-frequency and quantile dimensions.
References
- Adebayo, T. S., & Olanrewaju, V. O. (2024). How effective are trade policy and monetary policy in achieving a pathway to sustainable development? Evidence from a wavelet quantile‐on‐quantile Granger causality analysis. Sustainable Development, 33(1), 861-877. https://doi.org/10.1002/sd.3157
- Adebayo, T. S., & Özkan, O. (2024). Evaluating the role of financial globalisation and oil consumption on ecological quality: A new perspective from quantile-on-quantile granger causality. Heliyon, 10(2). https://doi.org/10.1016/j.heliyon.2024.e24636
- Adebayo, T. S., Olanrewaju, V. O., & Uzun, B. (2025). Do energy patents and energy prices drive the shift toward sustainable energy sources? A wavelet quantile-based analysis. Geoscience Frontiers, 102101. https://doi.org/10.1016/j.gsf.2025.102101
- Adebayo, T. S., Özkan, O., Uzun Ozsahin, D., Eweade, B. S., & Gyamfi, B. A. (2025). Exploring the role of ICT adoption technologies and renewable energy consumption in achieving a sustainable environment in the United States: an SDGs-based policy framework. Environmental Sciences Europe, 37(1), 20. https://doi.org/10.1186/s12302-025-01059-z
- Aharon, D. Y., Demir, E., & Umar, Z. (2025). On the connectedness between climate policy uncertainty, green bonds, and equity. Modern Finance, 3(1), 25-37. https://doi.org/10.3390/mf.v3i1.230
- Aydoğdu, A., & Çakır, H. M. (2025). Volatility Modelling of Cryptocurrencies According to Different Investment Horizons: The Case of Bitcoin. Journal of Mehmet Akif Ersoy University Economics and Administrative Sciences Faculty, 12(2), 724-749. https://doi.org/10.30798/makuiibf.1609311
- Aydoğdu, A., & Uyar, U. (2025). Enerji ve Kıymetli Metal Piyasaları Arasında Yayılım Etkisi: Wavelet Uyum Analizine Dayalı DCC-GARCH Yaklaşımı. Sosyoekonomi, 33(64), 557-585. https://doi.org/10.17233/sosyoekonomi.2025.02.24
- Barnett, M. (2023). Climate change and uncertainty: An asset pricing perspective. Management Science, 69(12), 7562-7584. https://doi.org/10.1287/mnsc.2022.4635
- Bouri, E., Iqbal, N., & Klein, T. (2022). Climate policy uncertainty and the price dynamics of green and brown energy stocks. Finance Research Letters, 47, 102740. https://doi.org/10.1016/j.frl.2022.102740
- Bouri, E., Rognone, L., Sokhanvar, A., & Wang, Z. (2023). From climate risk to the returns and volatility of energy assets and green bonds: A predictability analysis under various conditions. Technological Forecasting and Social Change, 194, 122682. https://doi.org/10.1016/j.techfore.2023.122682
- Broock, W. A., Scheinkman, J. A., Dechert, W. D., & LeBaron, B. (1996). A test for independence based on the correlation dimension. Econometric reviews, 15(3), 197-235. https://doi.org/10.1080/07474939608800353
- Chen, Z., Zhang, L., & Weng, C. (2023). Does climate policy uncertainty affect Chinese stock market volatility?. International Review of Economics & Finance, 84, 369-381. https://doi.org/10.1016/j.iref.2022.11.030
- Diaz-Rainey, I., Gehricke, S. A., Roberts, H., & Zhang, R. (2021). Trump vs. Paris: The impact of climate policy on US listed oil and gas firm returns and volatility. International Review of Financial Analysis, 76, 101746. https://doi.org/10.1016/j.irfa.2021.101746
- Dickey, D. A., & Fuller, W. A. (1979). Distribution of the estimators for autoregressive time series with a unit root. Journal of the American statistical association, 74(366a), 427-431. https://doi.org/10.1080/01621459.1979.10482531
- Dong, X., Wang, K. H., Tao, R., Sorana, V., & Moldovan, N. C. (2024). Is there a relationship between climate policy uncertainty and green finance? Evidence from bootstrap rolling window test. Economic Analysis and Policy, 82, 277-289. https://doi.org/10.1016/j.eap.2024.03.013
- Engle, R. F., Giglio, S., Kelly, B., Lee, H., & Stroebel, J. (2020). Hedging climate change news. The Review of Financial Studies, 33(3), 1184-1216. https://doi.org/10.1093/rfs/hhz072
- Gavriilidis, K. (2021). Measuring climate policy uncertainty. Available at SSRN 3847388. https://dx.doi.org/10.2139/ssrn.3847388
- Granger, C. W. (1969). Investigating causal relations by econometric models and cross-spectral methods. Econometrica: journal of the Econometric Society, 424-438. https://doi.org/10.2307/1912791
- Gulal, O. S., Topcu, M., Emirmahmutoglu, F., & Daud, A. F. (2025). Climate policy uncertainty and green bond markets. Environmental Research Communications. https://doi.org/10.1088/2515-7620/ade36b
- He, M., & Zhang, Y. (2022). Climate policy uncertainty and the stock return predictability of the oil industry. Journal of International Financial Markets, Institutions and Money, 81, 101675. https://doi.org/10.1016/j.intfin.2022.101675
- Hoque, M. M., Jakowski, N., & Prol, F. S. (2022). A new climatological electron density model for supporting space weather services. Journal of Space Weather and Space Climate, 12, 1
- Huo, D., Bagadeem, S., Elsherazy, T. A., Nasnodkar, S. P., & Kalra, A. (2023). Renewable energy consumption and the rising effect of climate policy uncertainty: Fresh policy analysis from China. Economic Analysis and Policy, 80, 1459-1474. https://doi.org/10.1016/j.eap.2023.10.017
- Husain, S., Sohag, K., & Wu, Y. (2022). The response of green energy and technology investment to climate policy uncertainty: An application of twin transitions strategy. Technology in Society, 71, 102132. https://doi.org/10.1016/j.techsoc.2022.102132
- Ilhan, E., Sautner, Z., & Vilkov, G. (2021). Carbon tail risk. The Review of Financial Studies, 34(3), 1540-1571. https://doi.org/10.1093/rfs/hhaa071
- Jarque, C. M., & Bera, A. K. (1980). Efficient tests for normality, homoscedasticity and serial independence of regression residuals. Economics letters, 6(3), 255-259. https://doi.org/10.1016/0165-1765(80)90024-5
- Khalfaoui, R., Mefteh-Wali, S., Viviani, J. L., Jabeur, S. B., Abedin, M. Z., & Lucey, B. M. (2022). How do climate risk and clean energy spillovers, and uncertainty affect US stock markets?. Technological Forecasting and Social Change, 185, 122083. https://doi.org/10.1016/j.techfore.2022.122083
- Kirikkaleli, D., Sowah Jr, J. K., Addai, K., & Altuntaş, M. (2023). Energy productivity and environmental quality in Sweden: Evidence from Fourier and non‐linear based approaches. Geological Journal, 58(9), 3452-3465. https://doi.org/10.1002/gj.4684
- Köycü, E. (2025). Possıble Effects of Uncertaınty Factors on Green Bond Returns. Pamukkale Üniversitesi Sosyal Bilimler Enstitüsü Dergisi, (68), 131-146. https://doi.org/10.30794/pausbed.1611428
- Lasisi, L., Omoke, P. C., & Salisu, A. A. (2024). Climate policy uncertainty and stock market volatility. Asian Economics Letters, 5(2). https://doi.org/10.46557/001c.37246
- Li, G., Li, Y., & Tsai, C. L. (2015). Quantile correlations and quantile autoregressive modeling. Journal of the American Statistical Association, 110(509), 246-261, https://doi.org/10.1080/01621459.2014.892007
- Liang, C., Umar, M., Ma, F., & Huynh, T. L. (2022). Climate policy uncertainty and world renewable energy index volatility forecasting. Technological Forecasting and Social Change, 182, 121810. https://doi.org/10.1016/j.techfore.2022.121810
- Liu, M. (2022). The driving forces of green bond market volatility and the response of the market to the COVID-19 pandemic. Economic Analysis and Policy, 75, 288-309. https://doi.org/10.1016/j.eap.2022.05.012
- Lv, W., & Li, B. (2023). Climate policy uncertainty and stock market volatility: Evidence from different sectors. Finance Research Letters, 51, 103506. https://doi.org/10.1016/j.frl.2022.103506
- Menteşe, B. (2021). Yeşil Tahvilin Gelişimi ve Türkiye’deki Uygulamaları. Uluslararası Muhasebe ve Finans Araştırmaları Dergisi, 3(1), 94-117. https://izlik.org/JA38YR87PC
- Naifar, N. (2024). Climate policy uncertainty and comparative reactions across sustainable sectors: Resilience or vulnerability?. Finance Research Letters, 65, 105543. https://doi.org/10.1016/j.frl.2024.105543
- Özkan, O., Adebayo, T. S., & Usman, O. (2024). Dynamic connectedness of clean energy markets, green markets, and sustainable markets: The role of climate policy uncertainty. Energy, 303, 131957. https://doi.org/10.1016/j.energy.2024.131957
- Özkan, O., Eweade, B. S., & Usman, O. (2024). Assessing the impact of resource efficiency, renewable energy R&D spending, and green technologies on environmental sustainability in Germany: evidence from a wavelet quantile-on-quantile regression. Journal of Cleaner Production, 450, 141992. https://doi.org/10.1016/j.jclepro.2024.141992
- Phillips, P. C., & Perron, P. (1988). Testing for a unit root in time series regression. biometrika, 75(2), 335-346. https://doi.org/10.1093/biomet/75.2.335
- Policy Uncertainty. (2025). Economic Policy Uncertainty Index. https://www.policyuncertainty.com
- Raza, S. A., Khan, K. A., Benkraiem, R., & Guesmi, K. (2024). The importance of climate policy uncertainty in forecasting the green, clean and sustainable financial markets volatility. International Review of Financial Analysis, 91, 102984. https://doi.org/10.1016/j.irfa.2023.102984
- Ren, X., Li, J., He, F., & Lucey, B. (2023). Impact of climate policy uncertainty on traditional energy and green markets: Evidence from time-varying granger tests. Renewable and sustainable energy reviews, 173, 113058. https://doi.org/10.1016/j.rser.2022.113058
- Schlenker, W., & Taylor, C. A. (2021). Market expectations of a warming climate. Journal of financial economics, 142(2), 627-640. https://doi.org/10.1016/j.jfineco.2020.08.019.
- Shabir, M., Ali, M., Hashmi, S. H., & Bakhsh, S. (2022). Heterogeneous effects of economic policy uncertainty and foreign direct investment on environmental quality: cross-country evidence. Environmental Science and Pollution Research, 29(2), 2737-2752. https://doi.org/10.1007/s11356-021-15715-3
- Shang, Y., Han, D., Gozgor, G., Mahalik, M. K., & Sahoo, B. K. (2022). The impact of climate policy uncertainty on renewable and non-renewable energy demand in the United States. Renewable Energy, 197, 654-667. https://doi.org/10.1016/j.renene.2022.07.159
- Siddique, M. A., Nobanee, H., Hasan, M. B., Uddin, G. S., Hossain, M. N., & Park, D. (2023). How do energy markets react to climate policy uncertainty? Fossil vs. renewable and low-carbon energy assets. Energy Economics, 128, 107195. https://doi.org/10.1016/j.eneco.2023.107195
- Sim, N., & Zhou, H. (2015). Oil prices, US stock return, and the dependence between their quantiles. Journal of Banking & Finance, 55, 1-8. https://doi.org/10.1016/j.jbankfin.2015.01.013
- Sunday Adebayo, T., Abbas, S., Olanrewaju, V. O., & Uzun, B. (2025). Unpacking policy ambiguities in residential and commercial renewable energy adoption: a novel multivariate wavelet quantile regression analysis. Applied Economics, 1-22. https://doi.org/10.1080/00036846.2025.2590632
- Syed, Q. R., Apergis, N., & Goh, S. K. (2023). The dynamic relationship between climate policy uncertainty and renewable energy in the US: Applying the novel Fourier augmented autoregressive distributed lags approach. Energy, 275, 127383. https://doi.org/10.1016/j.energy.2023.127383
- Tian, H., Long, S., & Li, Z. (2022). Asymmetric effects of climate policy uncertainty, infectious diseases-related uncertainty, crude oil volatility, and geopolitical risks on green bond prices. Finance Research Letters, 48, 103008. https://doi.org/10.1016/j.frl.2022.103008
- Treepongkaruna, S., Chan, K. F., & Malik, I. (2023). Climate policy uncertainty and the cross-section of stock returns. Finance Research Letters, 55, 103837. https://doi.org/10.1016/j.frl.2023.103837
- Wang, C. W., Wu, Y. C., Hsieh, H. Y., Huang, P. H., & Lin, M. C. (2022). Does green bond issuance have an impact on climate risk concerns?. Energy Economics, 111, 106066. https://doi.org/10.1016/j.eneco.2022.106066
- Wang, H., Li, S., & Ma, Y. (2023a). Climate policy and financial system stability: evidence from Chinese fund markets. Climate Policy, 23(4), 395-408. https://doi.org/10.1080/14693062.2022.2104790
- Wang, J., Mishra, S., Sharif, A., & Chen, H. (2024). Dynamic spillover connectedness among green finance and policy uncertainty: Evidence from QVAR network approach. Energy Economics, 131, 107330. https://doi.org/10.1016/j.eneco.2024.107330
- Wang, K. H., Wang, Z. S., Yunis, M., & Kchouri, B. (2023b). Spillovers and connectedness among climate policy uncertainty, energy, green bond and carbon markets: A global perspective. Energy Economics, 128, 107170. https://doi.org/10.1016/j.eneco.2023.107170
- Yang, D. X., Jing, Y. Q., Wang, C., Nie, P. Y., & Sun, P. (2021). Analysis of renewable energy subsidy in China under uncertainty: Feed-in tariff vs. renewable portfolio standard. Energy Strategy Reviews, 34, 100628. https://doi.org/10.1016/j.esr.2021.100628
- Ying, W., Ramzan, M., Olanrewaju, V. O., Brika, S. K., & Abozrib, A. (2025). The role of democratic governance and patent innovations in advancing sustainable energy transition. Energy & Environment, 0958305X251343060. https://doi.org/10.1177/0958305X251343060
- Yu, J., Zhang, M., Liu, R., & Wang, G. (2023). Dynamic effects of climate policy uncertainty on green bond volatility: an empirical investigation based on TVP-VAR models. Sustainability, 15(2), 1692. https://doi.org/10.3390/su15021692
- Zhu, P., Lu, T., & Wei, Y. (2025). Can Chinese green bond play a long-run safe haven for different crude oil under multiple uncertainties? A comparative analysis with the US green bond. Applied Economics Letters, 32(6), 812-816. https://doi.org/10.1080/13504851.2023.2289416


