The Ghana Stock Exchange (GSE) is a key indicator of economic performance, offering insights into investor sentiment, corporate health, and broader economic trends. However, as an emerging market, the GSE exhibits high volatility. This paper is to analyse the volatility nature of the GSE by considering the characteristics, influencing factors, volatility periods, modeling and forecasting and its implication for investors and policy decision makers.
Volatility Characteristics
Using the Hurst Exponent, it was found that past trends influence future movements, indicating that the GSE Composite Index (GSE-CI) follows structured patterns rather than random fluctuations. This is what experts referred to as the Long-Term Memory. Its Hurst exponent values range from 0.69 to 0.98, suggesting a long-term memory of 0.69 to 0.98, which means that the market movement has a certain degree of persistence and the future movement can be inferred to some extent based on past trends.
Analysis of daily market returns from 2011 to 2022 revealed frequent sharp increases and declines, highlighting higher risk exposure for investors. In “Heavy-Tailed Market Returns” the GSE-CI return series shows a heavy-tailed distribution, with kurtosis reaching 34.06, indicating that extreme price swings are relatively common.
High-volatility periods tend to be followed by more volatility, a phenomenon known as “Volatility Clustering”. This suggests that investors and policymakers should anticipate prolonged instability rather than isolated fluctuations. The study found that the GSE-CI return series exhibits volatility clustering, with its Ljung-Box Q-statistic for autocorrelation at lag 10 being 192.3, which is statistically significant at the 1% level, indicating significant autocorrelation in the squared returns.
Volatility Influencing Factors
Macroeconomic factors are the main causes of volatility in the GSE market. Economic policy shifts, such as changes in interest rates, inflation, and fiscal policies, can affect investor confidence and thereby influence market volatility. For instance, high inflation may lead investors to adjust their investment portfolios, causing stock prices to fluctuate. Additionally, exchange rate fluctuations, commodity price swings, and foreign investment patterns can create external shocks to the market. The depreciation of the Ghanaian cedi, for example, may impact the profitability of listed companies and, in turn, affect stock prices.
Volatility in GSE may also be influenced by Market Liquidity Factors. Compared to developed markets, the GSE has lower liquidity, with limited trading activity. This can result in more dramatic price swings and higher volatility. When market liquidity is insufficient, even small trades may cause significant price changes, amplifying market volatility.
One of the less emphasised characteristics on the high volatility nature of the GSE activities is the “Investor Sentiment and Behavior”. During the COVID-19 pandemic, the study found that overconfident market participants in Ghana engaged in excessive trading, significantly contributing to the weekly volatility observed during the pandemic period. The research also showed that the GSE exhibits leverage effects, meaning that negative shocks have a greater impact on volatility than positive shocks of the same magnitude. However, during the COVID-19 pandemic, positive shocks had a relatively larger impact on GSE returns than negative shocks of the same intensity.
Political factors are also key acts that influence the volatility of GSE. Political instability or changes in government policies can negatively affect investor confidence and lead to increased market volatility. For example, elections or policy adjustments may trigger uncertainties about the future economic outlook, prompting investors to adopt a wait-and-see approach or adjust their investment strategies, thereby causing stock prices to fluctuate.
Volatility During Specific Periods
A study by Prempeh et al. found that prior to the COVID-19 pandemic (Pre COVID Period), adverse shocks had a greater impact on the volatility of the GSE than positive shocks of the same intensity. The EGARCH model revealed that negative shocks positively influenced return volatility by 38.15%, while positive shocks had a positive effect of 16.17%. The volatility persistence was approximately 21 days.
During the COVID-19 pandemic (COVID Period), the volatility of the GSE increased significantly, but the volatility persistence was relatively short-lived. Positive shocks had a more pronounced impact on return volatility than negative shocks of the same magnitude. Specifically, positive shocks positively influenced return volatility by 39.69%, while negative shocks had a positive effect of 26.09%. The volatility persistence was about 3.90 days. The leverage effect was still present during this period.
Market Volatility Modeling and Forecasting
Many studies have used GARCH (1,1) and GJR-GARCH (1,1) models to analyze the volatility of the GSE. For example, the study by Forson et al. found that the GSE is mean-reverting and takes approximately 35 days for the market to stabilize over time. The research by Prempeh et al. applied the exponential GARCH model and discovered leverage effects in all observed periods. This is referred to as the GARCH Class Models.
Mogital Analytics applied four variations of Bayesian Stochastic Volatility (SV) models to analyze and predict the movements of the GSE-CI over a 12-year period (2011–2022). Among them, the SV model with Student’s t Errors produced the lowest Root Mean Square Error (RMSE), making it the most effective in predicting market movements. This model is adept at capturing heavy-tailed distributions and extreme price swings common in the Ghanaian stock market.
Implications for Investors and Policymakers
Investors should recognize that the Ghanaian stock market follows patterns rather than random fluctuations. Given the frequent extreme swings, investment strategies should diversify to mitigate risks. Additionally, the volatility clustering phenomenon suggests that short-term fluctuations may persist for several months, so investors should adopt a long-term perspective and avoid being swayed by short-term market noise.
Regulatory frameworks, by policymakers, should be adjusted to account for prolonged volatility periods. Measures to enhance market liquidity should be strengthened, as a well-liquid market can help absorb shocks and stabilize returns. Providing reliable market data and ensuring transparency can boost investor confidence and attract foreign investments.
In summary, the GSE exhibits high volatility, influenced by a variety of factors. Investors and policymakers need to gain a deep understanding of its volatility characteristics and influencing factors to develop appropriate investment strategies and policy measures, thereby achieving better investment returns and promoting the stable development of the stock market.