In this paper the author examines the impact specifics of underwriter’s support on the liquidity of IPO market. It is hypothesized that the activities of underwriter will have the grea-test impact on liquidity for the market of so-called «tepid» offerings. To confirm the hypothesis dynamics of changes in IPO market liquidity for different offering types was measured. As a measure of liquidity the author used market depth, which was estimated with applying of a linear regression model. The derived results allow to confirm the hypothesis and to determine the approximate period of increasing transaction cost for traders on the market of initial public offerings. At the end of the article the author points out factors to be considered for further research and refinement of the already obtained results.