Market Economy Sourcing Act This bill limits the content from nonmarket economy countries that may be included in free trade agreement qualifying goods. A nonmarket economy country is a foreign country that does not operate on market principles of cost or pricing structures, so that sales of merchandise in such country do not reflect the fair price of the merchandise. The bill requires that, during the five-year period following entry into force of a free trade agreement, no more than 20% of a qualifying good may originate in a nonmarket economy country, and no more than 10% thereafter.