You can round up all the investment bankers, all the C-Suite executives
and all the Wharton and Harvard MBA Students
and teach them Ethics
and it will make no difference.
What makes a difference is the person's Values.
Ethics is a defined as a philosophy of systematizing and recommending concepts of right and wrong.
Values are what you deem important to your life,
the actions you are willing to take because they gives meaning to your life.
Just knowing right from wrong does not solve the problem;
sometimes people discover doing the wrong thing is best if their values are selfish or greedy.
The US Army has core values:
loyalty - duty - selfless service - integrity
Our constitution has core values:
life - liberty - the pursuit of happiness
My business has core values:
integrity - professionalism - caring - teamwork - stewardship
Find your core values, and the ethics will follow.