be exchanged across countries. The organization of such international trade has long been studied to elucidate the impact of the international relations, geography and sociocultural factors on trade fluxes [@tinbergen1962analysis], as represented by e.g., the gravity model [@anderson2010gravity; @barigozzi2010multinetwork], as well as the topology of the trade network of countries [@PhysRevE.68.015101; @PhysRevLett.93.188701].

The fluctuation of trade volumes of various products also carries valuable information on human economic activities. As a country’s portfolio of exports is crucial for both its immediate success in the global market and long-term development [@hidalgo2007product; @hidalgo2009building; @hausmann2011network; @tacchella2012new], political and economic agents often shift their investment strategy from one product to another, which affect the market share of related products. Aggregated together, a huge number of such strategy shifts across countries, time, and products cause fluctuations of products’ shares, which can provide a clue for understanding a principle of capital management towards best benefiting from producing and exporting selected goods.

Here we report our finding of a scaling behavior of the annual variation of trade products’ shares in international trade. It is shown to imply that capital invested for various product categories, identified here with their shares, tends to move to and from popular products, the 