1. The Basic Exchange Contracts
There is a general consensus among Islamic jurists on the view that currencies of different countries can be exchanged on a spot basis at a rate different from unity, since currencies of different countries are distinct entities with different values or intrinsic worth, and purchasing power. There also seems to be a general agreement among a majority of scholars on the view that currency exchange on a forward basis is not permissible, that is, when the rights and obligations of both parties relate to a future date. However, there is considerable difference of opinion among jurists when the rights of either one of the parties, which is same as obligation of the counterparty, is deferred to a future date.
To elaborate, let us consider the example of two individuals A and B who belong to two different countries, India and US respectively. A intends to sell Indian rupees and buy U.S dollars. The converse is true for B. The rupee-dollar exchange rate agreed upon is 1:20 and the transaction involves buying and selling of $50. The first situation is that A makes a spot payment of Rs1000 to B and accepts payment of $50 from B. The transaction is settled on a spot basis from both ends. Such transactions are valid and Islamically permissible. There are no two opinions about the same. The second possibility is that settlement of the transaction from both ends is deferred to a future date, say after six months from now. This implies that both A and B would make and accept payment of Rs1000 or $50, as the case may be, after six months. The predominant view is that such a contract is not Islamically permissible. A minority view considers it permissible. The third scenario is that the transaction is partly settled from one end only. For example, A makes a payment of Rs1000 now to B in lieu of a promise by B to pay $50 to him after six months. Alternatively, A accepts $50 now from B and promises to pay Rs1000 to him after six months. There are diametrically opposite views on the permissibility of such contracts which amount to bai-salam in currencies. The purpose of this paper is to present a comprehensive analysis of various arguments in support and against the permissibility of these basic contracts involving currencies. The first form of contracting involving exchange of countervalues on a spot basis is beyond any kind of controversy. Permissibility or otherwise of the second type of contract in which delivery of one of the countervalues is deferred to a future date, is generally discussed in the framework of riba prohibition. Accordingly we discuss this contract in detail in section 2 dealing with the issue of prohibition of riba. Permissibility of the third form of contract in which delivery of both the countervalues is deferred, is generally discussed within the framework of reducing risk and uncertainty or gharar involved in such contracts. This, therefore, is the central theme of section 3 which deals with the issue of gharar. Section 4 attempts a holistic view of the Sharia relates issues as also the economic significance of the basic forms of contracting in the currency market.
2. The Issue of Riba Prohibition
The divergence of views1 on the permissibility or otherwise of exchange contracts in currencies can be traced primarily to the issue of riba prohibition.
The need to eliminate riba in all forms of exchange contracts is of utmost importance. Riba in its Sharia context is generally defined2 as an unlawful gain derived from the quantitative inequality of the countervalues in any transaction purporting to effect the exchange of two or more species (anwa), which belong to the same genus (jins) and are governed by the same efficient cause (illa). Riba is generally classified into riba al-fadl (excess) and riba al-nasia (deferment) which denote an unlawful advantage by way of excess or deferment respectively. Prohibition of the former is achieved by a stipulation that the rate of exchange between the objects is unity and no gain is permissible to either party. The latter kind of riba is prohibited by disallowing deferred settlement and ensuring that the transaction is settled on the spot by both the parties. Another form of riba is called riba al-jahiliyya or pre-Islamic riba which surfaces when the lender asks the borrower on the maturity date if the latter would settle the debt or increase the same. Increase is accompanied by charging interest on the amount initially borrowed.
The prohibition of riba in the exchange of currencies belonging to different countries requires a process of analogy (qiyas). And in any such exercise involving analogy (qiyas), efficient cause (illa) plays an extremely important role. It is a common efficient cause (illa), which connects the object of the analogy with its subject, in the exercise of analogical reasoning. The appropriate efficient cause (illa) in case of exchange contracts has been variously defined by the major schools of Fiqh. This difference is reflected in the analogous reasoning for paper currencies belonging to different countries.
A question of considerable significance in the process of analogous reasoning relates to the comparison between paper currencies with gold and silver. In the early days of Islam, gold and silver performed all the functions of money (thaman). Currencies were made of gold and silver with a known intrinsic value (quantum of gold or silver contained in them). Such currencies are described as thaman haqiqi, or naqdain in Fiqh literature. These were universally acceptable as principal means of exchange, accounting for a large chunk of transactions. Many other commodities, such as, various inferior metals also served as means of exchange, but with limited acceptability. These are described as fals in Fiqh literature. These are also known as thaman istalahi because of the fact that their acceptability stems not from their intrinsic worth, but due to the status accorded by the society during a particular period of time. The above two forms of currencies have been treated very differently by early Islamic jurists from the standpoint of permissibility of contracts involving them. The issue that needs to be resolved is whether the present age paper currencies fall under the former category or the latter. One view is that these should be treated at par with thaman haqiqi or gold and silver, since these serve as the principal means of exchange and unit of account like the latter. Hence, by analogous reasoning, all the Sharia-related norms and injunctions applicable to thaman haqiqi should also be applicable to paper currency. Exchange of thaman haqiqi is known as bai-sarf, and hence, the transactions in paper currencies should be governed by the Sharia rules relevant for bai-sarf. The contrary view asserts that paper currencies should be treated in a manner similar to fals or thaman istalahi because of the fact that their face value is different from their intrinsic worth. Their acceptability stems from their legal status within the domestic country or global economic importance (as in case of US dollars, for instance).
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ISLAMIC FOREX TRADING by Dr Mohammed Obaidullah
There is a general consensus among Islamic jurists on the view that currencies of different countries can be exchanged on a spot basis at a rate different from unity, since currencies of different countries are distinct entities with different values or intrinsic worth, and purchasing power. There also seems to be a general agreement among a majority of scholars on the view that currency exchange on a forward basis is not permissible, that is, when the rights and obligations of both parties relate to a future date. However, there is considerable difference of opinion among jurists when the rights of either one of the parties, which is same as obligation of the counterparty, is deferred to a future date. 
The Forex market is a non-stop cash market where currencies of nations are traded, typically via brokers. Foreign currencies are constantly and simultaneously bought and sold across local and global markets and traders' investments increase or decrease in value based upon currency movements. Foreign exchange market conditions can change at any time in response to real-time events. 
