The purpose of the research is to examine how firm characteristics such as profitability, size, growth opportunity, tangibility, non-debt tax shield, effective tax rate and liquidity affect leverage. The selected sample will consist of 100 companies listed on S&P 500. The dada for this research will be financial figures of these companies from 2012 to 2015 and will be collected via DataStream. The proposal should follow the structure provided in the attachment.