The study looked at how different rules and ownership of banks in over 60 countries affect how well banks work and how stable they are. They found that limiting what banks can do with securities, insurance, and real estate doesn't seem to make much difference in how well the banking sector, securities markets, and competition work. Mixing banking with other businesses doesn't have any positive effects. Countries that have strict rules on what banks can do with securities are more likely to have big banking problems. Mixing banking with other businesses can make the financial system less stable. Countries with more state-owned banks tend to have weaker banks, nonbanks, and stock markets.