A plaintiff has a great concern not only on whether he/she can deserve to win compensatory claims but on how much he/she collects through the action. The latter issue has not been drawn any attraction by scholars despite of its practical importance. Case laws have evolved on the area. Among torts cases, the comparative negligence rule was firstly recognized because it is articulated in the article 396 of Korean Civil Code. But, there are several considerations except for the plaintiff's negligence which courts should take into account to calculate actual damage. Since several years ago, the Korean Supreme Court stated to accept some considerations to limit liability except for comparative negligence. In 2007, it rendered two very crucial judgments concerning to the issue on the former Securities and Exchange Act. This paper is dedicated to the analysis on one of these two cases to reveal the importance of the case. After a sincere analysis, the ruling is said to be a good news and bad news. For a good news, it established a new way of limiting the amount of liability in addition to comparative negligence which is derived from the statute. The Korean Supreme Court didn't recognize a proportional causation because of a great burden of administering costs. However, damage is composed of an actual harm inflicted by the illegal act and a previously existing defect which the defendant is not liable for. When a proportional causation is not recognized, a supplementary rule is required to differentiate the actual harm from the previously existing defect. It was the limitation of liability that the Korean Supreme Court tried to develop to resolve this issue since 10 years ago. The case analyzed in this paper is evaluated to be of a great importance in that the Korean Supreme Court explicitly declared to establish a new consideration to limit liability without any statutory authority. For a bad news, it made the benefit of an article of the Korean Securities and Exchange Act weak. The article was introduced to give an incentive to the plaintiff,investors of securities, to file lawsuits against directors/officers and their accountants who reviewed financial reports.