Why do some countries like China thrive economically despite of corruption? The effect of corruption on economic efficiency is moderated by whether a society has an extensive informal social network such as the guanxi network in China. In societies with a thick, extensive informal social network, bribery-corruption relationship can be easily established and the risk of being reported is low. This relation-based trust makes the dissemination of corruption goods--the sale of government goods for private gains--more market-based. The competition among potential bribers increases the efficiency of corruption (or making corruption less wasteful). In societies that lack such strong informal networks and trust, corruption is more predatory and therefore a dead weight on the economy.