The study looked at how ownership concentration in European companies affects their performance. They found that having multiple large shareholders can improve firm performance, with the best results seen when the largest shareholder owns around 10% of the company. Companies with direct control from founder owners or management tend to perform well, while those controlled by government or financial institutions may not do as well. The study suggests that restructuring ownership and control can help improve firm performance, and that the impact of ownership and control varies depending on the country and industry.