In Seoul and Gyeonggi-do, demand for houses and commercial buildings steadily increases. Basically, this phenomenon is ascribed to the fact that about half the population of Korea lives in these regions. On the other hand, supply of houses and commercial buildings is suppressed for the Policy to Control the Development of the Capital Region, etc. As a result, many social conflicts, including Yongsan Tragic Incident in 2009, have arisen. The Yongsan Tragic Incident in 2009 took place, among other things, for recouping a premium. The premium system is universally used, collateral to commercial building lease. However, there is no written law that explicitly provides the premium system. Instead, there are some cases, including Korean Supreme Court 2000. 9. 22, 2000 Da 6326. For this reason, many disputes on premium system have arisen. In this Article, I`d like to make the legal principles on the premium clear to prevent such disputes. In this Article, first of all, I`d maintain that we should lay a duty for former lessee, etc. to guarantee a chance for latter lessee, etc. to recoup a premium as a collateral performance duty. To demonstrate this argument, I examined the questionnaire survey conducted by KDI(Korea Development Institute) Economic Information and Education Center. It seems that according to the questionnaire survey, there is an implicit agreement between former lessee, etc. and latter lessee, etc. for former lessee, etc. to guarantee a chance for latter lessee, etc. to recoup a premium. And then I analyzed a firm case, that is, Korean Supreme Court 2000. 9. 22, 2000 Da 6326, based on the questionnaire survey.