信用证是一种广泛运用于各种商业交易中的金融工具。从功能来上讲，信用证是开证人根据开证申请人的申请向受益人开立的一种附条件的付款承诺：只要受益人提交的单据与信用证规定的条款严格相符，开证人必须履行其付款承诺。
　　信用证可以分为很多种，不同种类的信用证适用的场合不同。不过，根据特有的功能与用途，现代信用证有两种基本形式：商业信用证与备用信用证。
　　商业信用证是信用证的传统形式，是国际货物买卖中的付款和融资工具。一个典型的商业信用证交易的流程如下：假设一位纽约的卖主欲将某种设备卖给一位上海的买主，然而买卖双方互不相识，双方对彼此的经济实力、诚实可靠性互为担心。卖方担心，在他将货物装运后，买方可能会资不抵债或拒绝付款；如果买方不履行其付款义务，卖方不仅可能要另外花费大笔资金在人生地不熟的上海起诉买方，而且可能还得承担额外费用在一个陌生的地方处理货物。同样，买方也没有理由相信卖方的偿付能力和可靠性。买方担心，自己预付货款后可能出现货物与合同约定不符的情形，或者情况更为糟糕：卖方资不抵债，自己钱货两空。
　　如果把诸如遥远的距离、语言、货币、文化差异以及外国法律等等不定因素考虑在内，国际货物买卖中商人们之间互相缺乏信任是不难理解的。为了减少交易各方的这种合理担心，买卖双方同意采用一种折中的办法：信用证交易。在信用证交易中，买方同意去向第三方（通常为银行）申请开立以卖方为受益人的信用证。如果银行接受开证申请人的申请并开立信用证，说明它同意只要卖方提交的单据与信用证的规定严格相符，它将对卖方提交的信用证项下的汇票承担直接、独立的承兑付款责任。


　　以上例子说明，一个典型的商业信用证交易涉及三方当事人、三项交易。三方当事人为：（1）被称为“开证申请人”、“付帐方”或者“客户”的买方；（2）被称为“受益人”的卖方；（3）被称为“开证人”、“开立行”或者“开证行”的银行。三项交易为：（1）买卖双方之间的基础交易-在此交易中，卖方同意将货物卖给买方，买方同意以信用证方式向卖方支付货款；（2）买方和银行之间的交易-在此交易中，银行同意开立以卖方为受益人的信用证；买方同意偿还开证人根据信用证规定支付的款项，并付给银行一定的佣金；（3）银行与卖方之间的交易，即信用证本身-在此交易中，银行同意只要卖方提交的单据与信用证的规定严格相符，银行将对卖方承担第一性的付款责任。
　　这种安排具有很强的实用性。在通常的交易过程中，各方当事人均可从中受益。卖方或受益人在向开证人交单之前始终保留着对货物的所有权，在交单时它或者得到付款或者得到其所交的汇票的承兑。由于银行信用代替了买方信用，卖方几乎避免了得不到付款的风险。除非出现欺诈，买方或开证申请人可以保证在付款银行收到信用证项下的单据之前它的货款不被支付出去，而信用证项下的单据不仅表明卖方已经履行买卖合同项下的义务，而且代表合同货物的所有权。在信用证交易中，因为无论卖方还是买方谁都不能同时占有货物与货款，所以滥用权利的问题得到了遏制。银行作为服务提供者，也可以从中收到一定的佣金。虽然银行看起来似乎在买方偿付前要承担向买方提供信贷的风险，但是银行通常不仅会将卖方提交的信用证项下的单据作为质押担保，而且还会要求买方提供其他财产作为担保。
　　备用信用证在法律架构上与商业信用证完全相同。一个简单的备用信用证交易同样涉及三方当事人（开证申请人、开证人与受益人）和三项交易（基础交易、申请协议与信用证本身）。
　　但是，备用信用证在用途上与商业信用证不同。备用信用证被用来在开证申请人没有履行基础合同或者基础合同的履行有瑕疵的意外情况出现时向受益人提供担保或补偿的。备用信用证的使用范围非常广泛。用著名信用证专家德兰教授的话来说：“备用信用证在使用范围上几乎没有什么限制。原则上，它可以适用于任何当事人可以履行的合同。”（见约翰?德兰《信用证法：商业信用证与备用信用证》1996年修订版，第一章第24页)。
　　备用信用证的广阔的适用范围在加拿大的RosenvPullen案中或许已被体现的淋漓尽致。在此案件中，备用信用证被用来为婚约的履行作担保。不过相对而言，备用信用证的使用在某些行业和交易中更为广泛。经常使用备用信用证的情形有：（1）在建筑业中，用来保护工程业主的利益，以防止承包方迟延履行、不当履行或不履行承包合同；（2）在金融业中，商业公司借助信誉好的银行资信，用来提高其长期商业票据或公司债券的信用度；（3）在国际货物买卖中，保证所售机器或设备的性能或售后服务质量。
　　尽管商业信用证与备用信用证姓同一个“姓”，而且二者具有同样的法律性质，但是二者还是有一些重要区别。第一，二者的商业目的不同：在商业信用证交易中，由于受益人一般会适当履行其合同义务，信用证为受益人提供的是一种安全的付款方式；而在备用信用证交易中，信用证则被用作一种违约担保工具，即在偶而的开证申请人对合同的履行有瑕疵或不履行合同时，用来向受益人提供担保或补偿。因为绝大多数基础合同是可以得到适当履行的，所以商业信用证的开证人一般来说是期待付款的，而备用信用证的开证人通常则是不准备付款的。第二，在商业信用证交易中，受益人提交的单据通常包括提单和商业发票，用以表明其已经适当履行基础合同；而备用信用证的付款则仅仅要求受益人出示一种开证申请人没有履行或者没有完全履行基础合同义务的文件。第三，备用信用证在很多情况下的风险要比商业信用证项下的大。商业信用证的安全性很高，因为商业信用证项下的文件常常不仅由第三人提供，而且代表着货物的所有权，或者至少可以从表面上证明受益人装运了合同规定的货物。而备用信用证项下的付款请求则通常只有受益人自己提供的书面声明，尽管有的备用信用证也会要求诸如工程监理证或法院判决等由第三人出具的文件。因此，备用信用证交易中潜在的意外或明目张胆的欺诈情形要比商业信用证交易中的多得多。也就是说，即使备用信用证本身所担保的意外情况没有发生，请求付款或获得付款的情形却有可能发生。一旦此类情况发生，开证申请人不但履行了基础合同，而且还得偿付银行已经支付的信用证项下的款项。万一开证申请人资不抵债，开证银行本身就得承担其中的风险。
　　
　　Commercial and Standby Letters of Credit
　　
　　By Gao Xiang, Vice President, Qinhuangdao Intermediate People‘s Court; Distinguished Fellow, Tim Fisher Centre for Global Trade and Finance, Bond University, Australia
　　
　　The letter of credit can functionally be defined as an instrument, issued by an issuer for the account of the applicant to the beneficiary, promising that it will honor a draft or a demand for payment made by the latter provided that terms and conditions specified in the credit are complied with.
　　Letters of credit can be categorized in many ways. Different types of letters of credit may operate differently. However, modern letters of credit can be divided into two basic forms according to their distinctive function and usage: commercial letters of credit and standby letters of credit.
　　Commercial letters of credit are a traditional form of letter of credit created as a payment and financing mechanism for international sales of goods. A prototypal commercial letter of credit operates as follows. Assume a seller in New York wishes to sell some machinery to a buyer in Shanghai. The seller and the buyer, however, may not know each other and each is concerned over the other‘s financial strength and reliability. The seller is worried that, after it has gone to the expense of shipping the goods, the buyer may become insolvent or refuse to pay for the goods upon arrival. If the buyer does not pay, the seller may have to go to great expense to sue the buyer in Shanghai, an unfamiliar foreign jurisdiction, and incur further expense in disposing of the goods in an unfamiliar territory. Similarly, the buyer has no reason to trust the seller‘s solvency and reliability and is concerned that it may not get the goods contracted if it pays in advance or even worse, that the financial collapse of the seller will leave it without both the money and the goods.
　　When variables such as distance, language, currency, culture and foreign laws are taken into consideration, a merchant‘s lack of confidence may be understood. In order to assuage each other‘s legitimate fears, the parties may agree to a compromise and arrange their transaction by way of a letter of credit. Under such an arrangement, the buyer agrees to go to a third party, normally a bank, and apply for a letter of credit in favor of the seller. When the bank accepts its application and issues a letter of credit, it agrees to assume the direct and independent obligation to honor the seller‘s draft presented under the letter of credit provided that complying documents specified in the credit are tendered.
　　This example illustrates that a typical commercial letter of credit transaction involves three parties and three transactions.1 The three parties are: (1) the buyer, known as the "applicant", the "account party" or the "customer"; (2) the seller, known as the "beneficiary"; and (3) the bank, known as the "issuer", the "issuing bank" or "opening bank". The three transactions are: (1) the underlying transaction between the buyer and the seller, under which the seller agrees to sell the goods to the buyer and the buyer agrees to pay to the seller the purchase price by way of a letter of credit; (2) the transaction between the buyer and the bank, under which the bank agrees to issue the letter of credit in favor of the seller and the buyer agrees to reimburse the bank for the payment made under the letter of credit plus a commission; and (3) the transaction between the bank and the seller, i.e., the letter of credit itself, under which the bank agrees to take the primary responsibility to honor the seller‘s draft provided it is accompanied by required documents specified in the letter of credit.
　　Such an arrangement has a high degree of commercial utility, and in the normal course of business benefits all the parties concerned. The seller/beneficiary retains the ownership of the goods until it presents the documents to the issuer, at which time it is paid or its draft is accepted by the issuer. The seller faces almost no risk of non-payment as the credit of the issuer is substituted for that of the buyer. The buyer/applicant is, subject to the problem of fraud, assured that its money will not be released until the required documents, which not only are the evidence indicating that the seller has completed its obligation under the sales contract, but also represent the ownership of the contracted goods, are presented to the paying bank. Abuse of the system is restrained by the fact that neither the seller nor the buyer is ever in control of the goods and the money at the same time. The bank, whose business is providing services, in turn gets paid a fee. Although it may seem that the bank assumes the risk of extending credit to the buyer until reimbursed, the bank usually takes security, a pledge, over the tendered documents, and often over other assets from the buyer as general security as well.
　　Standby letters of credit legally operate in the same basic framework as commercial letters of credit. A simple standby letter of credit transaction also involves three parties (the applicant, the issuer and the beneficiary) and three transactions (the underlying transaction, the application agreement and the letter of credit itself).
　　However, unlike commercial letters of credit, standby letters of credit are used to provide security or indemnity to the beneficiary for the contingency of the applicant‘s defective- or non-performance. They can be used in a wide range of transactions.2 In the words of Professor Dolan:
　　There are virtually no limits to the variety of transactions that the standby credit can serve. In principle, standby credits can be used in any contract where the performance of one party is executory.3
　　The potential breadth of use of standby letters of credit is perhaps most strikingly demonstrated by the Canadian case of Rosen v Pullen,4 where a standby letter of credit was used to guarantee performance of a marriage promise. Nonetheless, there are some industries and transactions where standby letters of credit are used more often than in others. In particular, standby letters of credit are used, (1) in the construction industry, to protect the owner of a construction project against late performance, faulty performance or nonperformance of a contractor; (2) in the financial industry, to bolster corporate issues of commercial paper or take corporate bond issues on the long term market, as a company can take advantage of the credit rating of a reputable bank; and (3) in international sales of goods, to guarantee service to or performance of the machinery or equipment purchased.
　　Although commercial letters of credit and standby letters of credit have the same "family name",5 and although in legal analysis they are of the same nature, nevertheless there are major differences between the two. First, the commercial purposes of the two kinds of letters of credit are distinctive. While the commercial letter of credit provides the beneficiary with a secure mechanism for payment due to its regular performance of a commercial obligation, the standby letter of credit is designed as a default instrument to provide security or indemnity to the beneficiary for the hopefully unlikely contingency of the applicant‘s defective- or non-performance. Because most underlying contracts are expected to be adequately performed, the issuer of the commercial letter of credit normally expects to pay, whereas the issuer of the standby letter of credit does not normally expect to pay. Secondly, while a commercial letter of credit is payable upon the presentation by the beneficiary of documents, which usually include a bill of lading and a commercial invoice, showing that it has properly performed the underlying contract, payment of a standby letter of credit is triggered by the presentation of a document attesting that the applicant has not, or has not properly, performed its obligation under the underlying contract. Thirdly, a standby letter of credit is in its most common form more risky than a commercial letter of credit. While the commercial letter of credit provides a high degree of security by requiring documents that confer title or at least evidence of shipment of apparently conforming goods which are often generated from independent third parties, the requirement for a claim under a standby letter of credit is often only a written statement by the beneficiary itself, although some standby letters of credit may require documents issued by independent third parties, such as a certificate of an engineer or a decision by a court. Therefore, the potential for sharp practice and outright fraud is far greater in the use of standby credits than it is with commercial credits. In other words, payment of a standby letter of credit may be demanded and obtained even though the contingency has not in fact occurred. If this happens, the applicant, in addition to having performed its obligation in the underlying transaction, will have to reimburse the bank that has made the payment in accordance with the terms of the credit. This kind of risk in some cases may have to be borne by the bank if the applicant is found to be insolvent.