A. The Korea National Housing Corporation (the Korea National Housing Corporation and the Korea Land Corporation were merged with the defendant on October 1, 2009; hereinafter the same shall apply) obtained approval of a housing construction project plan that newly constructs public rental housing units on and around December 10, 2001 in the BB block in the Sungsung City.

B. Around September 2004, the Defendant leased the instant apartment (hereinafter “the instant apartment”) following the completion of the construction in Sungsung-si apartment in accordance with the said housing construction project, and around October 2009, the period of mandatory lease of the instant apartment has expired with the lapse of the period of sale for sale. Around October 2009, the Defendant announced that the construction cost of a household corresponding to 60.90 square meters of the instant apartment shall be KRW 95,184,00, KRW 75.79, KRW 118,242,00, and KRW 84.87 square meters of the construction cost of a household corresponding to 75.79 square meters of the instant apartment, each of which shall be calculated as KRW 132,028,00,000, and notified the occupants of the instant apartment to enter into a sales contract with the Defendant.

Accordingly, the Plaintiffs listed in the separate sheet No. 2 signed each sales contract (hereinafter “each sales contract of this case”) with the Defendant on the relevant apartment as indicated in the “Dong and lake” column in the separate sheet No. 2 list among the apartment of this case.

C. The Plaintiffs listed in the separate sheet No. 2 were fully paid to the Defendant the sales price according to each of the instant sales contracts.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 1, Eul evidence Nos. 1 to 3 (including paper numbers), the purport of the whole pleadings

2. The pre-sale conversion price of the instant apartment should be calculated in accordance with the standards prescribed by relevant statutes, such as the former Rental Housing Act (amended by Act No. 9863, Dec. 29, 2009). The Defendant determined the excess amount as the parcelling-out price and received each payment from the Plaintiffs, thereby unjust enrichment. As such, the Defendant included the statutory interest from April 21, 201 to the date of the instant lawsuit.