The Glass-Steagall Act was passed in 1933 to place a dividing wall between commercial banking and investment banking. It was in an effort to protect consumers and the economy from the risks of speculative investment banking.
JP Morgan and other large institutions were targeted. The act was partially repealed and replaced in 1999 by the Gramm-Leach-Bliley Act. After 2008, some opined that the repeal of the original act contributed to the financial crises, and they instituted the Volcker Rule, which reinstated part of the original Glass-Steagall act.
A new 21st Century Glass-Steagall Act has been introduced, but its outcome may hinge on the 2016 election, as of the time of this writing.