1. CONTENTS (1) RESEARCH OBJECTIVES The purpose of this study is to evaluate factors determining the winning bid of real estate trust property. (2) RESEARCH METHOD Investigating winning bid case of real estates trust company and using Excel2007 program as a actual proof analysis tool, this research analyzed by building option model optimized for Public sale of real estates trust company. (3) RESEARCH FINDINGS It is the most important in this research that this research is the first research about factors which affect the winning bid of collateral trust estate which is the largest part of trust estate amounting to about 179 trillion won, when disposing of property for public sale resulting from the loss of benefit of time. 2. RESULTS To research about factors which affect the winning bid when disposing of property for public sale in South korea, This research analyzed biddropping(the winning bid/the first public sale price) as a dependent variable, a total of 16 factors (region, land area, land category, legal floor area ratio, use district, the first public sale price, amount of loan/the first public sale price, officially assessed land price/the first public sale price, a priority beneficiary, the number of public sale, public sale period, trust period, mean price of the last 3 dealing, KOSPI variable-cost ratio, average CD interest rate, rate of increase in land price) as independent variables. And as a meaningful variable which affect biddropping, a total of 12 independent variables (region, land area, legal floor area ratio, use district, the first public sale price, amount of loan/the first public sale price, the number of public sale, public sale period, KOSPI variable-cost ratio, average CD interest rate, rate of increase in land price) are discovered.