David Ricardo David Ricardo was born in 1772 and he was a stock trader and political economist from the United Kingdom. His work was influential in the way he systemized economics as argued by John Stuart Mill, Thomas Malthus and Adam Smith among other classical economists. Ricardo contributed significantly as a businessman, Member of Parliament, speculator and a financier; Ricardo developed comparative advantage theory which favored specialization in individuals and free trade in nations depending on the jurisdictions (Ricardo On the Principles 19).