Abstract: Based on SMEs financing market in China, a mathematical model is constructed to reveal the disadvantaged individual disclosure information mechanism in the collective form under the condition of information asymmetry. It is found that not only there is information disclosure optimization, but also there exists the problem of insufficient scale effect when exchanging between strong individuals and weak individuals, therefore, in real life, they exchange difficultly. The research shows that, to certain extent, information asymmetry can make vulnerable individuals with a strong individual achieve win-win situation in the course of exchange. When disadvantaged individuals could not normally disclosure information, they can bind together and disclosure information in strong collective form. Thus it improves the condition of the information asymmetry in both sides, the collective disclosure of information also can make the disadvantaged individuals information internal in order to exchange easily with strong ones. Furthermore, it can create scale effect.

Key words: information disclosure, optimization, exchange