maker's prices are continually moving in liquid markets. However, at the moment each trade is executed, the law is in force (it would normally be against exchange rules to break it). The law also need not apply if buyers have less than perfect information about where to find the lowest price. In this case, sellers face a tradeoff between the frequency and the profitability of their sales. That is, firms may be indifferent between posting a high price (thus selling infrequently, because most consumers will search for a lower one) and a low price (at which they will sell more often, but earn less profit per sale). The Balassa-Samuelson effect argues that the law of one price is not applicable to all goods internationally, because some goods are not tradable. It argues that the consumption may be cheaper in some countries than others, because nontradables (especially land and labor) are cheaper in less-developed countries. This can make a typical consumption basket cheaper in a less-developed country, even if some goods in that basket have their prices equalized by international trade. Prerequisite absence of trade frictions free competition price flexibility The law of one price has been applied towards the analysis of many public events, such as: In 2015, An International Monetary Fund working paper found that the law of one price holds for most tradeable products in Brazil but does not apply in the same way to its non-tradeable goods. A director of the Council on Foreign Relations held in 2013 that the then-current Apple iPad mini followed the law of one price, as far as its price nearly reached the same US dollar exchange rate in each applicable country. Indonesian governmental oil subsidies against oil smugglers; The smugglers selling stolen government-discounted oil back to its market rate. An apparent violation of the law involving international Royal Dutch/Shell stocks. After merging in 1907, holders of Royal Dutch Petroleum (traded in Amsterdam) and Shell Transport shares (traded in London) were entitled to 60% and 40% respectively of all future profits. Royal Dutch shares should therefore automatically have been priced at 50% more than Shell shares. However, they diverged from this by up to 15%. This discrepancy disappeared with their final merger in 2005. In recent years the company has had two different shares, "A" and "B" shares. Although each carries the same rights to dividends etc, they usually trade at different