PERFORMANCE OF SECTOR INDEXES IN THE NIGERIAN STOCK EXCHANGE: INSIGHT FROM UNI VARIATE STATISTICS AND CORRELATION

Abstract

The objective of this paper is to evaluate the performance of Nigerian Stock Exchange (NSE) sector indexes. Specifically, the paper estimates and compares the univariate statistics and correlation coefficients of the NSE all-share index, banking index, consumer goods index, oil & gas index, NSE 30 index, insurance index, industrial goods index, pension index, and alternative securities market index using daily sector indices ranging from 02 July 2008 to 31 December 2015. The univariate statistics obtained from the NSE sectors returns show that the average rates of return for all the NSE sectors returns for the study period is zero, except the insurance sector which exhibit negative returns. The skewness coefficients of the all-share index, industrial goods index and pension index are positive, whereas those of banking index, consumer goods index, NSE 30 index, and insurance index are negative. All the sectors returns are leptokurtic. Results of the Jarque-Bera Normality tests show that all the sectors returns are not normally distributed. The estimates from the correlation analysis show very weak relationship between the sectors, except for a very strong association between the banking index and the NSE 30 index. These insights have applications in portfolio selection and management.

JEL Classification Numbers: G11, G23, C43

1. Introduction

It is well established among finance scholars and professionals that stock market sectors information allows investors and scholars to observe the performance of a particular stock in relation to other stocks and/or stock index. Campello, Giambona, Graham and Harvey (2011) indicate that overall market conditions have large effects on the prices of individual stocks. Hence, understanding the behaviour of market indices and the various industry groups can be a valuable tool in portfolio management. Stock market sector analysis also provides the basis for benchmarking the performance of a particular stock or sector as well as guide to domestic and international diversification of investments.

The principle of portfolio diversification describes the optimal combination of portfolio returns and risks required to maintain expected portfolio return. It stresses the importance of selecting portfolio components that have low correlation in their returns as well as low covariance (see, Markowitz, 1952; Cappiello, Engle & Sheppard, 2006; Emenike, 2015). Analysing the performance of stock market sectors will reveal the nature of interaction between the sector, which will in turn form basis for portfolio selection and investment decisions.

Stock markets are usually divided into sectors by industry classification. Each of the sectors or combination of sectors has an index, which reflects the general sector(s) movement. Stock market Index, according to Guha, Dutta and Bandyopadhyay (2016), is considered as a barometer to judge the sentiment of the market. The index is usually monitored by different stock market stakeholders, such as financial markets researchers and analysts for providing accurate analysis, investors to purchase or sell financial assets, policy makers for future policy formulation, and so on. The Nigerian Stock Exchange (NSE) created and maintains eleven indexes, which are all-share index, banking index, consumer goods index, oil & gas index, NSE 30 index, insurance index, industrial goods index, pension index, premium index, lotus Islamic index, and alternative securities market index.

Numerous empirical studies have recently been conducted to examine the correlation between sectors of stock markets both in developed and developing economies (see for example, Sharabati, Noor and Saymeh, 2013; Cao, Long & Yang, 2013; Rajamohan and Muthukamu, 2014; Yilmaz, Sensoy, Ozturk & Hacihasanoglu, 2015; Guha, Dutta and Bandyopadhyay, 2016); however the performance and correlations of sectors and their portfolio diversification implications have not been explored adequately in the NSE. Comparative analysis of the NSE sectors indexes will provide investors with an idea of how well a given group of companies are expected to perform as a whole. Thus there is need for empirical comparative analysis of the sectors of the NSE.

The objective of this study is to evaluate and compare the performance of sectoral indexes of the NSE. Specifically, the paper aims at conducting a comparative analysis of univariate statistics and correlation among the NSE all-share index, banking index, consumer goods index, oil gas index, NSE 30 index, insurance index, industrial goods index, pension index, and alternative securities market index. This study is useful to investors (both individual and institutional), regulators of the NSE, and future researchers. To the investors for instance, the empirical findings of this study will provide information required to benchmark the performance of a particular stock, sector or industry. In addition, the performance of the sectors has application in both domestic and international diversification of investments. The findings will also provide basis for the review of poorly performing sectoral indexes in the NSE. The regulators can therefore formulate policies that can enhance performance of such sectors of the market. The study is also useful to researchers as it contributes to knowledge on the performance of sectoral indexes in Nigeria and serve as reference material to future study. The remainder of the paper is organised as follows: the next section presents an overview of the NSE Indexes and brief review of empirical literature. Section three contains methodology and description of data, while section four provides empirical results and discussion. Finally, section five provides the summary and concluding remarks.