The rise of user-friendly and zero-commission online trading platforms attracted retail investors in the financial markets, allowing accessibility even for investors with no financial background. The study analyses retail investors’ behaviour in comparison with the institutional investors by considering their investment activities on a set of stocks with respect to the market conditions (SP500, VIX, stock market price, stock market volume). The results show that retail investors tend to invest in moments of high market volatility, instead institutional investors tend to be risk averse. For both, the investment activities are positively related to market volumes, and regarding prices, retail investors tend to follow a contrarian strategy for the stocks which have low financial performances.