This study examines how relatives, defined as family, friends and partners, influence Swedish stock investors investment decisions and strategies on the stock market. Based on theories of information cascades, prospect theory and self-determination theory, a quantitative survey study was conducted with 167 respondents. The study analysed the relationship between relatives influence compared to the individual’s gender, age and risk preference. The results show that relatives have a measurable impact on investment decisions. Women report to a greater extent than men that they are influenced by relatives, while older and more risk-averse investors tend to be less likely to follow advice from relatives. The study highlights how social influence can reduce investor autonomy and contribute to herd behaviour in the market.