Mohammad Rezaei Kheirabadi - Master of Business Administration (MBA), Amirkabir University of technology, tehran, iran,
Amir Hossein Nimjerdi, - Master of Business Administration (MBA), Amirkabir University of technology, tehran, iran,
Ali Ziaeefard - Master of Business Administration (MBA), Amirkabir University of technology, tehran, iran,

In this research, we try to first explain a little about the formation of Lehman Brothers investment bank. Also, the scope of its activities and the cases that led to its bankruptcy will be investigated. In this article, the main focus is on mortgages in that period. Then the problems arising from the three dimensions of the bank, the government and the people will be examined. Then, the role of each of the dimensions in ethical issues created from different perspectives such as duties (Ross and Kant), utilitarianism (rule, based and practice-based), double effect Tampering , the formula of universal law and rationality are examined , which seems to be the role of the bank in the problems that.have arisen

Business ethics, Lehman Brothers, mortgages, adjustable-rate mortgages, Great Depression