Can Limits to Arbitrage Explain Stock Price Idiosyncratic Volatility Premium Puzzle in China’s A-Share Market?

Investigating the existence and causes of idiosyncratic volatility premium puzzle in developing stock market can enrich the research on this asset pricing puzzle. To investigate the existence and whether limits to arbitrage in China’s A-share market can explain the idiosyncratic volatility premium puzzle, this paper uses listed stocks in China’s A-share market from 2002 to 2019 as a sample. We calculate three individual measures and one comprehensive measure of limits to arbitrage based on Chinese specific regulations. After that, we conduct univariate portfolios analysis, regression analysis, and bivariate portfolios analysis to obtain evidence. We prove that idiosyncratic volatility premium puzzle exists in China’s A-share market and is robust and that limits to arbitrage in this market can partly explain this asset pricing puzzle. This paper enriches research on asset pricing anomaly and can help us evaluate the effect of China’s A-share market reform.

Evolved attitudes to risk and the demand for equity

The equity premium puzzle refers to the observation that people invest far less in the stock market than is implied by measures of their risk aversion in other contexts. Here, we argue that light on this puzzle can be shed by the hypothesis that human risk attitudes were at least partly shaped by our evolutionary history. In particular, a simple evolutionary model shows that natural selection will, over the long haul, favor a greater aversion to aggregate than to idiosyncratic risk. We apply this model—via both a static model of portfolio choice and a dynamic model that allows for intertemporal tradeoffs—to show that an aversion to aggregate risk that is derived from biology may help explain the equity premium puzzle. The type of investor favored in our model would indeed invest less in equities than other common observations of risk-taking behavior from outside the stock market would imply, while engaging in reasonable tradeoffs over time.

The Equity Risk Premium Puzzle in Pakistan

Our study uses the consumption-based asset-pricing power utility model to test theEquity Risk Premium (ERP) puzzle in Pakistan. The study has collected monthly stock pricedata from July 1997 to December 2017 from the PSX data portal. We extracted informationabout macroeconomic factors such as inflation and risk-free interest rate from the State Bankof Pakistan. Moreover, the study used private consumption and population data from thePakistan Bureau of Statistics. The results suggest that the ERP puzzle has a strong occurrencein Pakistan, a phenomenon previously associated with only developed markets. Onedisadvantage of the present investigation is the small sample size. A longer time durationcould have reduced short-term biases. Past researchers have suggested different approachesfor solving the equity premium puzzle. For instance, some studies used improvised structuralmodels to justify the equity risk premium puzzle using macroeconomic factors.

Solution to the Equity Premium Puzzle

This study provides a solution of the equity premium puzzle. Questioning the validity of the Arrow-Pratt measure of relative risk aversion for detecting the risk behavior of investors, a new tool in the form of the sufficiency factor of the model was developed to analyze the risk behavior of investors. The calculations of this newly tested model show that the value of the coefficient of relative risk aversion is 1.033526 by assuming the value of the subjective time discount factor as 0.99. Since these values are compatible with the existing empirical studies, they confirm the validity of the newly derived model that provides a solution to the equity premium puzzle.

The equity premium

This chapter explains ‘the equity premium puzzle’ and ‘the risk-free rate puzzle’. The chapter starts out comparing historical returns on stocks to historical returns on bonds, as well as the risks associated with these returns. The standard models economists use to explain the relative sizes of stock and bond returns, and hence the equity risk premium, are based on the exposure of stocks and bonds to economic growth. The chapter explains why these standard theories fail to explain the size of the equity premium. The chapter also explains how economists have changed their workhorse models to reconcile why returns on stocks are so high compared to bond returns. Another key insight in the chapter is that the equity premium does not depend linearly on economic growth in itself, but on the volatility of economic growth and its correlation with stock returns. Two countries can experience the same level of average economic growth, but different volatilities of consumption growth and correlations between consumption growth and stock returns, causing stock returns to differ between countries. This is one more reason why Chapter 6 finds that economic growth does not line up with stock returns across countries.