Abstract
This paper is an attempt in analysing time-scale dependence of systematic risk of stocks for an emerging market economy. Financial markets all over the world are characterized by heterogeneous investors. For example, different investors have different time horizons of investment which in turn is highly related to perception of risk of different investors in holding these stocks. Also, in emerging market economies, economic conditions are very fluid. Not only new firms are joining the market but existing firms themselves are changing rapidly; they are expanding into new markets, and at times with different products. Therefore, assuming that the risk in holding a firm's stock will be constant over a longer period is rather a restrictive assumption. Also, Indian equity markets are one of the most dynamic equity markets in the world today.
The last decade has been the most eventful period for the Indian securities market. Resource mobilization in the primary market has increased dramatically, rising sixfold between 2000 and 2010 (NSE, 2010), which is having a very significant impact on the risk-return trade-off in the secondary market. Market capitalization has grown substantially over the period indicating that not only more companies are using the stock markets for resource mobilization today but overall market participation has also increased considerably.
This paper tests for time-scale stability of beta of different trading stocks in the Indian equity market, using wavelet filters following Gencay et al (2002; 2005) and Fernandez (2006) and finds considerable instability in beta estimates. Based on this analysis, time-scale dependent beta estimates are provided for all the stocks under consideration.
Time-scale dependent estimates of systematic risk embedded in different stocks will provide considerable information to practitioners in terms of benefits of diversification while constructing different portfolios using different stocks traded in Indian equity markets. Essentially, with the tools explained in this paper, practitioners will be able to incorporate their horizons of investment while planning for portfolio diversification. Also, the results emphasize the importance of a hedging strategy that varies over different time horizons of investments over a strategy where the hedge ratio is invariant to different time horizons.