Abstract: Mark Granovetter emphasized the effect of ongoing systems of social relations in economic actions. This paper analyzes the data from the field work from 2004 to 2008 to study the ongoing interaction between the networks of social relations and the economic actions in a critical case of a bicycle black market. The conclusion is as follows: each individual black bicycle dealer is in a predicament with a limited inventory to satisfy potential customers’ varying demands. However, if all dealers in the black market are considered, the entire inventory is then sufficient. Thus, the key of the black market is how to pass the information of diversified demands on to the right dealer. And networks of social relations can accomplish this. The networks in the current case are not based on kinship or geographical ties; they originate from the economic actions in the black market. An initial network starts to form through dealers getting to know people or la guanxi and then get fortified through showing loyalty or righteousness (jiang yiqi) in the ongoing trading. Such social networks have promoted information transmission, raised the entrusting level, created a transaction model for reciprocal benefits, reduced risks, and produced better profits of the black market activities. Furthermore, as economic actions continue, the social networks continue to change. Gradually, when the information and trust develop to a certain level, a Cartel is reached among the bicycle black dealers regarding bicycle providers and consensus prices, which in turn changes the operation in the black market and an even higher profit is attained. That underground economic actions are through intermediary activities and that information transmission is swift prevent the networks from turning into a mafia. Such networks can also serve as a force to foil potential malfeasance to protect the market order.

Key words: networks of social relations , underground economic , bicycle black market ,  , information , trust , potential malfeasance