The study looked at how big U.S. banks have become and whether it's a good idea to limit their size. By analyzing data from 2006 and 2015, the researchers found that many banks actually save money as they get bigger. This means they can be more efficient and make more profit. The top four largest banks in the U.S. were found to benefit the most from getting bigger. So, while some people worry about banks growing too large, this study suggests that bigger banks can actually be more cost-effective.