This study sought to model the stock market return volatility at the Nairobi Securities Exchange (NSE) in the presence of structural breaks. Using daily NSE 20 share index for the period 04/01/2010  to  29/12/2017,  the market return volatility was modeled using different GARCH type models and taking into account four endogenously identified structural breaks. The market exhibited a non-normal distribution that was leptokurtic and negatively skewed and also showed evidence for ARCH effects, volatility clustering, and volatility persistence. We found that by considering structural breaks, volatility persistence was reduced, while leverage effects were found to lead to explosive volatility. In addition, investors were not rewarded for taking up additional risk since the risk premium was insignificant for the full period. However, during explosive volatility, investors were rewarded for taking up more risk. Moreover, we found that risk premium, leverage effects, and volatility persistence were significantly correlated. The GARCH (1,1) and TGARCH(1,1) models were found to be the best fit models to test for symmetric and asymmetric effects respectively. While the GARCH models were able to provide evidence for the stylized facts in the NSE, we conclude that the presence or absence of these features is period specific. This especially relates to volatility persistence, leverage effects, and risk premium effects. Caution should, therefore, be taken in using a specific GARCH model to forecast market return volatility in Kenya. It is thus imperative to pretest the data before any return volatility forecasting is done.

This study sought to evaluate the relationship between equity unit trust fund flows measured as purchases and sales and the Nairobi Securities Exchange (NSE) stock market return. The study employed Vector Autoregressive model and tested for Granger causality using monthly data for the period starting January 2010 to December 2017. The granger causality results showed that equity fund sales contain information that can explain stock market return and stock market return contain information that can explain equity fund purchases thus unidirectional causality. Impulse response results showed that equity fund purchases have a predominantly positive relationship with NSE stock market return and NSE stock market return have a positive relationship with equity fund purchases. This implies that an increase in stock market return will lead equity fund managers to purchase more securities and as the equity fund purchases increase, the demand for those stocks will increase causing the stock prices to increase and consequently increase stock market return. In contrast, equity fund sales are predominantly negatively related with stock market return and stock market return is also negatively related to equity funds sales. As the stock market return increase, the equity fund managers will decrease their sales. As the sales increase, the supply for those stocks will increase causing a decrease in prices and consequently a decrease in stock market return. Equity fund sales explain the variation in stock market return more than equity fund purchases while stock market return is a determinant of equity fund purchases and equity fund sales.