早期學者著墨於投資人意見分歧與個股預期報酬、資產價格泡沫化、崩盤風險、獨特性風險負溢酬等領域，而本研究則是著重探討投資人意見分歧對個股獨特性風險之關係來彌補兩者關係為何，並進一步探討在牛熊時且市場風險較高情況下，投資人意見分歧對個股獨特性風險之影響，因此本研究以2012年1月1日至2022年12月31日為樣本期間，主要以多元迴歸探討投資人意見分歧對個股獨特性風險之關係，並以牛熊時且市場風險較高的情境下，投資人意見分歧對個股獨特性風險之關係為何，實證結果發現，(1)投資人意見分歧對個股獨特性風險存在正向顯著影響，(2)投資人意見分歧對於下一期之個股獨特性風險仍存在正向顯著影響，投資人意見分歧具有預測效果，與過往文獻結果相符，(3)在當期與前一期牛時且市場風險較高的情況下，投資人意見分歧會減緩個股獨特性風險之正向效果，(4)在當期與前一期熊市且市場風險較高的情況下，投資人意見分歧對個股獨特性風險則無顯著影響。

Early scholars focused on issues such as investor disagreement, stock returns, asset price bubbles, crash risks, and the negative risk premium of idiosyncratic risk. However, this study explores the relationship between investor disagreement and the idiosyncratic risk of stocks to bridge the gap between these factors. It further examines the impact of investor disagreement on idiosyncratic risk during periods of high market risk in both bull and bear markets. The sample period spans from January 1, 2012, to December 31, 2022. This study primarily employs multiple regression analysis to investigate the relationship between investor disagreement and the idiosyncratic risk of stocks, examining the dynamics under scenarios of high market risk during bull and bear markets. The empirical results indicate that: (1) investor disagreement has a significant positive impact on the idiosyncratic risk of stocks; (2) investor disagreement continues to significantly influence the idiosyncratic risk of stocks in subsequent periods, demonstrating predictive power and consistency with previous literature; (3) during both current and previous periods of bull markets with high market risk, investor disagreement mitigates the positive effect on idiosyncratic risk; (4) during both current and previous periods of bear markets with high market risk, investor disagreement has no significant effect on idiosyncratic risk.

周賓凰與劉怡芬(2000)台灣股市橫斷面報酬解釋因子：特徵、單因子、或。多因子？」，《證券市場發展季刊》，第45期，1-32
陳安琳(2002), 台灣股票報酬之穩定因素－交叉確認、因素分析與模擬分析,管理學報,19 (3), 519-542
Amihud, Y. (2002c). Illiquidity and stock returns: cross-section and time-series effects. Journal of Financial Markets, 5(1), 31–56. https://doi.org/10.1016/s1386-4181(01)00024-6
Ang, A., Hodrick, R. J., Xing, Y., & Zhang, X. (2006). The Cross‐Section of Volatility and Expected Returns. the Journal of Finance, 61(1), 259–299. https://doi.org/10.1111/j.1540-6261.2006.00836.x
Aabo, T., Pantzalis, C., & Park, J. C. (2017b). Idiosyncratic volatility: An indicator of noise trading? Journal of Banking & Finance, 75, 136–151. https://doi.org/10.1016/j.jbankfin.2016.11.003
Aragó, V., Barreda-Tarrazona, I., Breaban, A., Matallín, J., & Salvador, E. (2022b). Market risk aversion under volatility shifts: An experimental study. International Review of Economics & Finance, 80, 552–568. https://doi.org/10.1016/j.iref.2022.02.022
Boehme, R. D., Danielsen, B. R., & Sorescu, S. M. (2006b). Short-Sale Constraints, Differences of Opinion, and Overvaluation. Journal of Financial and Quantitative Analysis, 41(2), 455–487. https://doi.org/10.1017/s0022109000002143
Barberis, N., & Huang, M. (2008b). Stocks as Lotteries: The Implications of Probability Weighting for Security Prices. the American Economic Review, 98(5), 2066–2100. https://doi.org/10.1257/aer.98.5.2066
Brandt, M. W., Brav, A., Graham, J. R., & Kumar, A. (2009c). The Idiosyncratic Volatility Puzzle: Time Trend or Speculative Episodes? Review of Financial Studies/the Review of Financial Studies, 23(2), 863–899. https://doi.org/10.1093/rfs/hhp087
Bartram, S. M., Brown, G. W., & Stulz, R. M. (2016b). Why Does Idiosyncratic Risk Increase with Market Risk? Social Science Research Network. https://doi.org/10.2139/ssrn.2828666
Chan, K., & Hameed, A. (2006b). Stock price synchronicity and analyst coverage in emerging markets. Journal of Financial Economics, 80(1), 115–147. https://doi.org/10.1016/j.jfineco.2005.03.010
Chen, Z., & Petkova, R. (2012b). Does Idiosyncratic Volatility Proxy for Risk Exposure? Review of Financial Studies/the Review of Financial Studies, 25(9), 2745–2787. https://doi.org/10.1093/rfs/hhs084
Carlin, B. I., Longstaff, F. A., & Matoba, K. (2014b). Disagreement and asset prices. Journal of Financial Economics, 114(2), 226–238. https://doi.org/10.1016/j.jfineco.2014.06.007
Chen, L., Qin, L., & Zhu, H. (2015b). Opinion divergence, unexpected trading volume and stock returns: Evidence from China. International Review of Economics & Finance, 36, 119–127. https://doi.org/10.1016/j.iref.2014.11.012
Diether, K. B., Malloy, C. J., & Scherbina, A. (2002b). Differences of Opinion and the Cross Section of Stock Returns. the Journal of Finance, 57(5), 2113–2141. https://doi.org/10.1111/0022-1082.00490
Durnev, A., Morck, R., & Yeung, B. (2004b). Value‐Enhancing Capital Budgeting and Firm‐specific Stock Return Variation. the Journal of Finance, 59(1), 65–105. https://doi.org/10.1111/j.1540-6261.2004.00627.x
David, A. (2008). Heterogeneous Beliefs, Speculation, and the Equity Premium. the Journal of Finance, 63(1), 41–83. https://doi.org/10.1111/j.1540-6261.2008.01310.x
Duong, H. N., Kalev, P. S., & Krishnamurti, C. (2009b). Order aggressiveness of institutional and individual investors. Pacific-basin Finance Journal, 17(5), 533–546. https://doi.org/10.1016/j.pacfin.2009.05.001
Duarte, J., Kamara, A., Siegel, S., & Sun, C. (2011b). The Common Component of Idiosyncratic Volatility. Social Science Research Network. https://doi.org/10.2139/ssrn.1787006
Fama, E. F., & French, K. R. (1996). Multifactor Explanations of Asset Pricing Anomalies. the Journal of Finance, 51(1), 55–84. https://doi.org/10.1111/j.1540-6261.1996.tb05202.x
Foellmi, R., Legge, S., & Schmid, L. (2016c). Do Professionals Get It Right? Limited Attention and Risk‐taking Behaviour. the Journal of Economic, 126(592), 724–755. https://doi.org/10.1111/ecoj.12375
Garfinkel, J. A., & Sokobin, J. (2006). Volume, Opinion Divergence, and Returns: A Study of Post-Earnings Announcement Drift. Journal of Accounting Research, 44(1), 85–112. https://doi.org/10.1111/j.1475-679x.2006.00193.x
Garfinkel, J. A. (2009). Measuring Investors’ Opinion Divergence. Journal of Accounting Research, 47(5), 1317–1348. https://doi.org/10.1111/j.1475-679x.2009.00344.x
Garcia, R., Mantilla-García, D., & Martellini, L. (2014b). A Model-Free Measure of Aggregate Idiosyncratic Volatility and the Prediction of Market Returns. Journal of Financial and Quantitative Analysis, 49(5–6), 1133–1165. https://doi.org/10.1017/s0022109014000489
Harris, M., & Raviv, A. (1993b). Differences of opinion make a horse race. Review of Financial Studies/the Review of Financial Studies, 6(3), 473–506. https://doi.org/10.1093/rfs/6.3.473
Hong, H., & Stein, J. C. (1999b). A Unified Theory of Underreaction, Momentum Trading, and Overreaction in Asset Markets. the Journal of Finance, 54(6), 2143–2184. https://doi.org/10.1111/0022-1082.00184
Hong, H., & Stein, J. C. (2007b). Disagreement and the Stock Market. the Journal of Economic Perspectives, 21(2), 109–128. https://doi.org/10.1257/jep.21.2.109
Hou, K., & Loh, R. K. (2016b). Have we solved the idiosyncratic volatility puzzle? Journal of Financial Economics, 121(1), 167–194. https://doi.org/10.1016/j.jfineco.2016.02.013
Hasan, M. M., & Habib, A. (2017b). Firm life cycle and idiosyncratic volatility. International Review of Financial Analysis (Online)/International Review of Financial Analysis, 50, 164–175. https://doi.org/10.1016/j.irfa.2017.01.003
Hu, Y., Zhao, T., & Zhang, L. (2020b). Noise trading, institutional trading, and opinion divergence: Evidence on intraday data in the Chinese stock market. International Review of Economics & Finance, 68, 74–89. https://doi.org/10.1016/j.iref.2020.03.012
Huang, C., Lunawat, R., & Wang, Q. (2024b). Disagreement about public information quality and informational price efficiency. Journal of Financial Economics, 152, 103762. https://doi.org/10.1016/j.jfineco.2023.103762
Jiang, G. J., Xu, D., & Yao, T. (2009b). The Information Content of Idiosyncratic Volatility. Journal of Financial and Quantitative Analysis, 44(1), 1–28. https://doi.org/10.1017/s0022109009090073
Kearney, C., & Potì, V. (2007b). Have European Stocks become More Volatile? An Empirical Investigation of Idiosyncratic and Market Risk in the Euro Area. European Financial Management, 14(3), 419–444. https://doi.org/10.1111/j.1468-036x.2007.00395.x
Kang, J., Lee, E., & Sim, M. (2014b). Retail Investors and the Idiosyncratic Volatility Puzzle: Evidence from the Korean Stock Market. Asia-Pacific Journal of Financial Studies, 43(2), 183–222. https://doi.org/10.1111/ajfs.12044
Kim, J., Lee, C., Lee, W. H., Ok, Y., & Truong, T. T. T. (2022b). Idiosyncratic volatility, turnover and the cross-section of stock returns: evidence from the Korean stock market. International Journal of Emerging Markets, 18(12), 6192–6213. https://doi.org/10.1108/ijoem-09-2021-1499
Markowitz, H. (1952b). The Utility of Wealth. Journal of Political Economy, 60(2), 151–158. https://doi.org/10.1086/257177
Miller, E. M. (1977b). RISK, UNCERTAINTY, AND DIVERGENCE OF OPINION. the Journal of Finance, 32(4), 1151–1168. https://doi.org/10.1111/j.1540-6261.1977.tb03317.x
Malagon, J., Moreno, D., & Rodríguez, R. (2018b). Idiosyncratic volatility, conditional liquidity and stock returns. International Review of Economics & Finance, 53, 118–132. https://doi.org/10.1016/j.iref.2017.10.011
Nguyen, P., Zaied, Y. B., & Pham, T. P. (2019). Does idiosyncratic risk matter? Evidence from mergers and acquisitions. the Journal of Risk Finance, 20(4), 313–329. https://doi.org/10.1108/jrf-03-2018-0040
Nguyen, P., Zaied, Y. B., & Pham, T. P. (2019). Does idiosyncratic risk matter? Evidence from mergers and acquisitions. the Journal of Risk Finance, 20(4), 313–329. https://doi.org/10.1108/jrf-03-2018-0040
Roll, R. (1988). R2. the Journal of Finance, 43(3), 541–566. https://doi.org/10.1111/j.1540-6261.1988.tb04591.x
Tan, M., & Liu, B. (2016b). CEO’s managerial power, board committee memberships and idiosyncratic volatility. International Review of Financial Analysis (Online)/International Review of Financial Analysis, 48, 21–30. https://doi.org/10.1016/j.irfa.2016.09.003
Wang, H., & Hu, D. (2020b). Disagreement with procyclical beliefs and asset pricing. the North American Journal of Economics and Finance, 51, 101102. https://doi.org/10.1016/j.najef.2019.101102
Martin, I. W. R., & Papadimitriou, D. (2022). Sentiment and Speculation in a Market with Heterogeneous Beliefs. the American Economic Review, 112(8), 2465–2517. https://doi.org/10.1257/aer.20200505
Wang, J., Wu, K., Pan, J., & Jiang, Y. (2023b). Disagreement, speculation, and the idiosyncratic volatility. Journal of Empirical Finance, 72, 232–250. https://doi.org/10.1016/j.jempfin.2023.03.011
Xiouros, C., & Zapatero, F. (2024b). Disagreement, information quality and asset prices. Journal of Financial Economics, 153, 103774. https://doi.org/10.1016/j.jfineco.2023.103774
Yang, Y. C., Zhang, B., & Zhang, C. (2020b). Is information risk priced? Evidence from abnormal idiosyncratic volatility. Journal of Financial Economics, 135(2), 528–554. https://doi.org/10.1016/j.jfineco.2019.06.013