Around the world, near 46% of a company's stock is concentrated in the hands of the three main shareholders and, for companies that operate in South American markets, that percentage rises to 70%. After a portfolio study and panel data estimation conducted on 271 companies corresponding to five emerging South American markets, the article concludes that, on an average, the stock portfolio made up of companies with the greatest concentration of holdings generates higher yield than the yield produced by the portfolio made up of companies with lesser concentration of holdings. That indicates that stock investors require a higher yield, due to the greater risk they face as minority shareholders in companies with an elevated concentration of holdings.