本研究從風險分散的角度，探討近年來廣為討論的準被動式指數策略(Quasi-passive index strategy)，其中挑選三大投資組合策略--等權重(Equal Weighted Portfolio, EW)、風險平價(Naïve Risk Parity Portfolio, RP)、相關性極小化(Minimum Correlation Portfolio, MCP)，實證應用於元大台灣卓越50ETF，回測基準時間從2004年1月5日起至2016年12月30日止，共計13年。在實證分析中，除了探討一般的投資組合績效結果外，文中也進一步比較文獻回顧中各式風險分散測度指標，其中包含(1)風險分散比率(Diversification Ratio, DR)、(2)集中度比率(Concentration Ratio, CR)、(3)波動性加權平均相關性(Volatility-weighted Average Correlation)、(4)赫芬戴爾指數(Herfindahl Index, Index)等對各種策略的控制成效。 本研究的實證結果如下: 相關性極小化投資組合策略(MCP)在元大台灣卓越50ETF的實證應用下，雖然成分股集中配置於某特定產業類股(即集中度比率、赫芬戴爾比率相對較高)，但本策略透過「波動性加權平均相關性」顯著且有效的控制，使得成對資產的相關性極小化，最終達成風險分散的投資目標。 / This article discusses the recently most popular “Quasi-passive index strategy”, especially from risk diversification aspect. We select three major portfolio strategies, including Equal Weighted Portfolio (EW), Naïve Risk Parity Portfolio (RP), and Minimum Correlation Portfolio (MCP), and apply all of three to the Yuanta/ P-shares Taiwan Top 50 ETF in Taiwan. The back-test period of the strategy is from January 5th, 2004, to December 30th, 2016 (around 13 years). In the empirical analysis, we not only compare the performance and risk of different strategies, but also focus on a variety of the measurement of diversification, such as Diversification Ratio (DR), Concentration Ratio (CR), Volatility-weighted Average Correlation (ρ), and Herfindahl Index (HI), all of which can quantify the degree of diversification control. In the empirical result, we find that Minimum Correlation Portfolio (MCP), applied in the Yuanta/ P-shares Taiwan Top 50 ETF, will allocate highly concentrated on some specific industry (equivalently high CR and high HI). However, this strategy significantly and efficiently controls the factor of “Volatility-weighted Average Correlation (ρ)”. Therefore, MCP can minimize the coefficient correlation between each pair asset and achieve the goal of risk diversification.

El objetivo de este estudio es analizar el impacto de la diversificación sobre el rendimiento y el riesgo. Se emplea un panel de datos de frecuencia mensual para el periodo 2010-2019 y se utiliza el estimador de MGM por la naturaleza dinámica del modelo. Los resultados muestran que la diversificación de la cartera de préstamos no tiene efecto en el rendimiento del sistema bancario, sin embargo, se observa que los bancos con mayores riesgos pueden aumentar sus rendimientos si aumentan su nivel de concentración por sector económico y departamento. El efecto en el riesgo dependerá del tipo de concentración, un mayor nivel de concentración de préstamos por sector y departamento disminuirá el riesgo crediticio; pero una mayor concentración de préstamos por tipo de crédito aumentará el nivel de riesgo. Además, se observó que no hay ningún efecto sobre el riesgo ni el rendimiento dependiendo de si el banco es de capitales domésticos o extranjeros. Los hallazgos son importantes para los bancos al elegir su estrategia crediticia y clave para las autoridades regulatorias. / The objective of this study is to analyze the impact of diversification on performance and risk. A monthly frequency data panel is used for the period 2010-2019 and the MGM estimator is used because of the dynamic nature of the model. The results show that loan portfolio diversification does not affect the performance of the banking system, however, it is observed that banks with higher risks can increase their returns by increasing their level of concentration by economic sector and department. The effect on risk will depend on the type of concentration, a higher level of loan concentration by sector and department will decrease credit risk; but a higher concentration of loans by type of credit will increase the level of risk. Besides, it was noted that there is no effect on risk or return depending on whether the bank is domestic or foreign-owned. The findings are important for banks when choosing their credit strategy and key for regulatory authorities. / Trabajo de investigación

本研究探討費率自由化政策與台灣產物保險市場經營效益，利用實證資料評估產物保險公司之整體經營績效及核保利潤。本研究自保險年鑑、台灣經濟新報資料庫及保險市場重要指標，選取1998年至2006年間財務及業務資訊來進行實證分析。 依Klein (1999)分類，台灣產物保險市場屬於類似獨占性競爭市場，產物保險公司高度競爭。依實證結果顯示，實施費率自由化政策，公司自留費用率持續緩慢增加，自留綜合成本率亦呈現上升趨勢。多數產物保險公司之實際核保利潤仍大於依Fairley (1979)計算之均衡核保利潤。 實證結果摘要如下： (1) 類似獨占性競爭市場：赫芬多指數皆小於0.1，市場呈現競爭狀態。1996年後，火險及車險之簽單保費成長率似乎每四、五年會呈現負成長。另外，1998-2003年費用率與公司規模呈現顯著負相關(p=0.01)。2004-2006年，此負相關並不顯著(p=0.1)，顯示大公司漸不具有成本優勢，即產險市場之進入障礙有減少之趨勢。 (2) 成本費用支出增加：除2001年外，1998至2006年之產物保險公司自留綜合成本率介於91.09% 和 93.49%。2006年之自留綜合成本率為93.49%。2006年之產物保險公司費用率上升至40.51% 且損失率下降至52.97%。 (3) 核保利潤呈現正值：依Fairley(1979)計算之2006年預期均衡核保利潤。20家產物保險公司，17家實際核保利潤大於預期均衡核保利潤。 / This paper provides an empirical study of rate deregulation plan and profit performance in Taiwan property-liability insurance market. The data used in this study are from Insurance Year Book, Taiwan Economic Journal Data Bank, and Important Indexes of Insurance Industry (Taiwan) during the period from 1998 to 2006. Based on the classification by Klein (1999), the market structure of Taiwan property-liability insurance industry is similar to monopolistic competitive market and the property-liability insurers are engaged in intense competition. The results of this study show that the expense ratios of insurers rise slightly from year to year and the combined ratios also follow a trend of increase. The actual underwriting profits of most property-liability insurers are larger than the expected numbers estimated by using the methodology in Fairley (1979). The empirical results are as follows: (1) The market structure is similar to monopolistic competitive market for that the Herfindahl indexes are all below 0.1. The growth ratios of written premium on fire insurance and automobile insurance seem to become negative every four or five years after 1996. Besides, the negative correlation between expense ratio and the scale of economics in insurance market from 1998 to 2003 was significant at the p = 0.01 level. However, this correlation from 2004 to 2006 was not significant at the p = 0.1 level. It seems that larger insurers do not have significant cost advantages over smaller insurers in the recent years, namely the entry barriers decline. (2) The expenses and costs keep increasing. Except 2001, the combined ratios ranged from 91.09% in 1998 to 93.49% in 2006. The expense ratio increased to 40.51% while the net loss ratio decreased to 52.97% in 2006. (3) The underwriting profits of most insurers are positive. The expected underwriting profits by using the methodology in Fairley (1979) is less than the actual ones in 2006. Among the 20 property-liability insurers, the actual underwriting profits of 17 insurers were larger than their expected underwriting profits.