机会利益损失来源于司法实践，系经验法则的结果，法官通过拟制将其纳入法律保护范畴。基于人类行为与判断的可预测性，机会利益损失借助于认识论、主观概率等理论获得独立价值。法学语境下，机会利益损失是一种具体的、实质性的且有利于获得特定利益或避免特定损害的现实可能性的丧失，出于损害赔偿法意旨与法律政策考虑，应对机会所代表的利益投入以及对社会秩序规则的合理期待予以充分肯定。大陆法系国家侧重于机会利益损失的概念界定与理论归位。英美法系国家基于判例法体系特征，以合理确定性要求、因果关系规则为理论原点，对机会利益损失赔偿进行审慎探索，从机会利益的独立性、替代性角度寻求为受损方提供必要救济的正当性支持。本质而言，不同法系对于机会利益损失赔偿的探讨不谋而合，机会利益损失赔偿规则被视为平衡双方当事人利益的折中机制，在处理损失不确定性与补偿受损方真实的期待利益损失之间作出了务实性回应。鉴于机会利益的不确定性和发生的盖然性，各国司法实践对机会利益损失的救济保持谨慎态度。通过对案例进行类型化整合，机会利益损失存在于射幸合同、招投标合同、专业疏忽、虚假陈述、职业损害、利润损失等领域。检视案件事实与裁判规则可知，对机会的价值判断，是机会利益损失可赔偿性论证的基本前提。区分真正机会损失案件的标准不在于案件诉因、事件发生时点、当事人行为性质、损失是否具有可诉性等，而在于随机或者偶然性因素来源的存在，此识别过程兼具事实与价值判断双重属性。当合同含有明示或默示的机会承诺，或者机会表现为合同目的或是合同不可分割的一部分，或者违约利润损失或可得利益损失计算困难或难以举证证明（如缺乏可供参考的市场价格），或者因错误承诺或虚假陈述守约方放弃明确可识别的次优合同，或者市场波动或进入市场机会有限、无明确的市场可供参考时，机会利益损失通常会得到赔偿。当存在相关市场且业已形成稳定的市场价值，或者第三方须基于客观标准进行损害评估，或者损失来源于一系列不确定性事件集合，或者损害赔偿的变数源自合同当事人时，机会损失难以得到赔偿。从实证法角度考察，违约机会利益损失延展了期待利益范畴，法院事实上通过扩张损失类型以实现对机会利益损失的救济。适用机会利益损害赔偿的关键在于机会的可靠性评估与机会利益损失的经济价值评估，前者必须以证据为基础，后者可通过概率比例、抽象推定、综合衡量等方式，明确损害赔偿的计算方法与赔偿数额。

The loss of chance or opportunity comes from judicial practice and is the result of empirical rules. The judge incorporates it into the realm of legal protection through fictitious system.Based on the predictability of human behavior and judgment, the loss of chance or opportunity gains independent value by means of epistemology, subjective probability and other theories. In the context of law, the loss of chance or opportunity is a specific, substantial and realistic possibility that is conducive to obtaining specific interests or avoiding specific damages. Considering the intention of damages law and legal policies, the interest input represented by opportunities and the reasonable expectation for the rules of social order should be fully affirmed.The civil law countries focus on the concept definition and theoretical reorientation of the loss of chance or opportunity. Based on the characteristics of case law system, common law countries, with reasonable certainty requirements and causality rules as the theoretical origin, prudently explore the compensation for loss of chance or opportunity, and seek for the legitimate support to provide necessary relief for the aggrieved party from the perspective of independence and substitution of opportunity interest. In essence, different legal systems have coincided with the research on the compensation for loss of opportunity benefits. The rules of loss of chance damages are regarded as a compromise mechanism to balance the interests of both parties and provide a pragmatic response between dealing with the uncertainty of loss and compensating the real expectations of the aggrieved party.In view of the uncertainty and contingency of opportunity interest, the judicial practice of various countries maintains a cautious attitude towards remedies for loss of chance or opportunity. Through the type integration of cases, the loss of chance or opportunity exists in the fields of aleatory contracts, bidding contracts, professional negligence, misrepresentation, professional damage, loss of profits and so on. By examining the facts of the case and the adjudication rules, we can find that the value judgment of opportunity is the basic premise of the argument of the indemnification of the loss of chance or opportunity. The standard for distinguishing true lost chance cases does not lie in the cause of the case, the time of the incident, the nature of the party’s behavior, whether the loss is litigable, etc., but in the existence of random or contingent sources. This identification process has dual attributes of facts and value judgment. When the contract contains an express or implied promise of opportunity or chance, or the opportunity is manifested as the purpose of the contract or an integral part of the contract, or it is difficult to calculate or prove the loss of profits or gains from breach of contract (such as lacking of reference market prices) , or when the observant party abandons a clearly identifiable sub-optimal contract due to a false promise or misrepresentation, or when the market fluctuates or access to the market is limited and there is no clear market for reference, the loss of chance or opportunity benefits is usually compensated. Loss of opportunity is difficult to recover when a relevant market exists and a stable market value has been established, or a third party is required to assess the damage based on objective standards, or the loss derived from a series of uncertain events, or the variable of damages originates from the parties to the contract.From the perspective of empirical law, the loss of chance or opportunity in breach of contract extends the realm of expectation interests, and the court actually realizes the remedy for the loss of chance or opportunity by expanding the types of losses. The key to the enforcement of damages for loss of chance lies in the reliability assessment of the opportunity and the economic value evaluation of the loss of opportunity interest. The former must be based on evidence, while the latter can define the calculation method and amount of the compensation by means of probability ratio, abstract presumption and comprehensive measurement.