Under the scheme of Japanese City Renewal Law (JCRL), the cost of urban redevelopment projects is financed by revenues from selling reserved floors secured beforehand in a redeveloped building. The outcome of whether the reserved floor can be sold is unforeseeable, so entities for redevelopment are faced with risks in project financing. Defining the risks for the entities as a probability of loss and formalizing the urban redevelopment process as a game theoretic model, this paper aims to demonstrate that we can evaluate the actual risks entities will bear in a project by showing a hypothetical numerical example. The game theoretic model for urban redevelopment procedures was first constructed by Imanishi, Saito and Tanaka[1]. They attempted to evaluate what risks would be transferred from the Urban Renaissance (UR) Agency, a government entity for redevelopment authorized by JCRL, to the private sector if UR employed a new contract scheme under which UR delegates the disposition of the reserved floor to the constructor that makes a contract with UR to construct the redeveloped building. The model was formalized as a two-stage auction implemented by the entity for redevelopment. The first auction is carried out as a sealed bid lowest price auction to choose a constructor for the redeveloped building, and the second stage chooses a buyer for the reserved floor as a sealed bid highest price auction. They theoretically derive the risk born by the entity for redevelopment from the hypothetical case when true preference distributions for buyers and constructors are uniform distributions. While their derivation is innovative, they have derived the result for just one of four possible cases. In this paper we demonstrate derivations for all four cases to complete the risk calculation. JEL Classification: D44, D82, O22, R51