Philippe Bertrand

Affiliated member ,  Aix-Marseille Université , Institut d'administration des entreprises (IAE)

Econometrics, Finance and mathematical methods
Status
Professor
Research domain(s)
Finance
Contact
philippe.bertrand[at]univ-amu.fr
+33(0)4 13 55 25 28
Address

AMU - AMSE
5-9 Boulevard Maurice Bourdet, CS 50498
​13205 Marseille Cedex 1

Abstract Exloring the role of different types of investors on stock market is crticial since different types of investors react and behave differently when making investment decision. The role of investor behavior is a very important issue in an immature stock market like Vietnam stock market because the market is characterized by a large number of individual investors and low reporting standard. Institutional and foreign investors however play an influential role due to their large exposure and strong investment expertise. Clearly, examining the role of investor behavior and its impact on the stock market in Vietnam is an important topic in finance. A significant body of empirical research has shown that investor behavior is an essential factor to explain stock price that the classical financial theory cannot explain. This research examines the role of investor behavior in stock market by examining the relationship between investor behavior and stock return using the Vietnamese stock exchange data. We create a sentiment index using the principal components analysis (PCA). Consistent with the sentiment and stock return literature, the research shows a negative contemporaneous relationship between investor sentiment and market return.
Keywords Stock return, Investors sentiment, Foreign investors, Individual investors, Vietnam stock market, Investor behavior
Publication HAL Google Scholar
Abstract Purpose Although the solid empirical proof of momentum is documented in various stock markets, there are many debates among academics with respect to the source of momentum profit. The first aim of this paper is intensively re-examine the momentum profit in Vietnam, an important emerging market. Secondly, the authors study the return predictability of a measure of investors’ overreaction, then examine whether the momentum effect in Vietnam is explained by overreaction. Design/methodology/approach Using the weekly data of more than 300 non-financial Vietnamese stocks during 2009–2019, the authors build a measure of investors’ overreaction, which is based on trading volume and the sign of stock returns. Consequently, to investigate whether momentum exits after controlling for overreaction, the authors carefully compare trading strategies based on overreaction with price momentum strategies using adjusted returns and double sorts on past returns and levels of overreaction. Findings The article makes three main findings. Firstly, the authors discover the empirical evidence of momentum in the Vietnamese equity market. Secondly, the measure of overreaction could be a predictor of Vietnamese stock returns. Stocks that have experienced a stronger upward overreaction provide a higher average return. Finally, returns on trading strategies based on overreaction are robust after adjusting for momentum, while returns on momentum portfolios become insignificant after adjusting for overreaction. By double-sorting, the authors document that holding past returns constant, the average returns of portfolios rise monotonically with their measure of overreaction. Hence, the momentum profit in Vietnam arises from investors’ overreaction. Originality/value The paper extends previous research on the behavioral explanation of momentum in emerging stock markets, which has not been fully exploited in the literature.
Keywords Momentum, Overreaction, Overconfident investors, Stock returns, Trading strategy
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Abstract The literature is inconclusive on the source of the size effect. Our paper contributes to extant studies by investigating the relationship between the size premium and default risk in Vietnam, an important frontier emerging market. The debt-to-equity ratio and distance-to-default of Merton (1974, The Journal of Finance, 29, 449) are used as distress-risk proxies. Based on more than 300 listed stocks over 2009–2019, we discover that the small portfolio delivers the highest average return. The excess return on the small portfolio is concentrated in firms with high distress risk. Furthermore, neutral size factors are built to dissect returns on the Fama-French size factor from the default-risk premium. Empirical results prove that the explanatory power of the size factor is negatively affected when the default-risk neutrality is applied. Given this backdrop, the size premium in Vietnam is likely to be compensation for distress risk, consistent with a risk-based point of view.
Keywords Size premium, Fama-French, Distance-to-default, Default risk
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Abstract The objective of this paper is to emphasize the di¤erences between a call and a warrant as well as the di¤erent valuation methods of warrants which have been introduced in the nancial literature. For the sake of simplicity and applicability, we only consider a debt-free equitynanced rm. More recently a formal distinction between structural and reduced form pricing models has been introduced. This distinction is important whether one wishes to price a new warrant issue or outstanding warrants. If we are interested in pricing a new issue of warrants, e.g. in the context of a management incentive package, one has to rely on a structural model. However most of practitioners use the simple Black-Scholes formula. In this context, we analyze the accuracy of the approximation of the "true" price of a warrant by the Black-Scholes formula. We show that in the current low interest rate environment, the quality of the approximation deteriorates and the sensitivity of this approximation to the volatility estimate increases.
Keywords Warrant, Option, Black-Scholes
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Abstract The goal of this paper is to provide and examine an important extension of the usual portfolio insurance, namely to study the notion of portfolio performance participation. In this framework, the portfolio is based on two risky assets: the rst one corresponds to a reserve asset, while the second one is considered as an active asset which has usually both a higher mean and a higher variance. We aim at insuring a given percentage of the reserve asset return, whatever the market uctuations. The two main performance participation methods are the Option-Based Performance Participation (OBPP) and the Constant Proportion Performance Participation (CPPP). We compare these two portfolio strategies by means of various criteria such as their payo¤s at maturity, their four rst moments and their cumulative distributions functions. We also compare their dynamic hedging properties by computing in particular their deltas and vegas.
Keywords CPPP, OBPP, Performance participation, Portfolio insurance, CPPP
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Abstract In this article we extend the research on risk-based asset allocation strategies by exploring how using an SRI universe modifies properties of risk-based portfolios. We focus on four risk-based asset allocation strategies: the equally weighted, the most diversified portfolio, the minimum variance and the equal risk contribution. Using different estimators of the matrix of covariances, we apply these strategies to the EuroStoxx universe of stocks, the Advanced Sustainability Performance Index (ASPI) and the complement of the ASPI in the EuroStoxx universe from March 15, 2002 to May 1, 2012. We observe several impacts but one is particularly important in our mind. We observe that risk-based asset allocation strategies built on the entire universe, concentrate their solution on non-SRI stocks. Such risk-based portfolios are therefore under-weighted in socially responsible firms.
Keywords Turnover, Combinatorics, Alternative and risk-based strategies, Socially responsible investment, Theory of Computation, Diversification, Operation Research/Decision Theory, Performance, Robust covariances matrix
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Abstract This paper examines whether the initiation of Vigeo Corporate Social Performance (CSP) rating impacts company profiles. Using a sample of European listed firms, we confirm that there is a positive and significant relationship between CSP rating and a firm's liquidity and investor base. Consistent with the neglected stock effect, this relationship is sensitive to firm size. Our results have important implications for practitioners. Firstly, investment in Corporate Social Responsibility (CSR) could represent an alternative method of improving a company's stock market quality alongside liquidity provider contracting or market listing transfer. Secondly, when a firm's board investigates the opportunity to invest in CSR, it should consider the benefits of lowering the company's cost of capital through the aforementioned effects. Finally, from an asset manager's perspective, any change in CSP should be taken into account, as it can affect company valuation and therefore portfolio performance.
Keywords Cost of Equity Capital, Investor Base, Liquidity, Corporate social responsibility, Corporate Social Performance
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Abstract We analyze the performance of the two main portfolio insurance methods, the OBPI and CPPI strategies, using downside risk measures. For this purpose, we introduce Kappa performance measures and especially the Omega measure. These measures take account of the entire return distribution. We show that the CPPI method performs better than the OBPI. As a-by-product, we determine the set of threshold values for these risk/reward performance measures
Keywords Portfolio insurance
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