The initial public offering (IPO) of a company's shares leads to changes of the ownership structure of a company, from a private into a public one. It is usually assumed that the most common reason for 'going public' is the need to obtain funds for new investments. Yet, there are numerous other theories concerning the reasons behind IPO: selling of the company by its original owners; decentralization of control; obtaining funds to restore financial balance; increasing the value of a company as a part of its marketing strategy and many others. In the case of Poland and other countries undergoing systemic transformation, public share offering was often used as a method for the privatisation of state-owned companies.

The article analyses the impact of public share offerings in Poland on companies' financial results during the first three years after the IPO. Panel data was used for individual companies, for the period 1992 - 2001. 173 companies are included in the database during the period of nine years, which has yielded in 1 557 observations. Financial sector companies or companies floating their shares as a consequence of a privatisation process are excluded from the analysis. Chronological order of data is based on the IPO date. The book value of companies was considered, including: assets, liabilities, fixed assets, shareholders' equity, net profit, proceeds of sale, etc. The analysed changes in the book value of the companies depended on the times of data gathering relative to the IPO of a particular company and on the calendar year. Such a selection of variables enables elimination of the effect of cyclic fluctuations which were quite significant in the first years of the economic transformation in Poland.

The research was based on the PSCE method for panel data estimation. The book value considered in absolute terms and the book value as a share in assets served as company-specific variables. Binary variables indicating the moment vis-a-vis the IPO moment and the discrete variable indicating the calendar year were used as explanatory variables. The aim of the analysis was to verify the hypotheses suggesting that the IPO leads to company growth, decreased leverage and profitability and increased investments. The outcome of the research shows that, following an IPO, investments increase considerably but the debt remains unchanged. This means that the new funds obtained are actually used by companies for investments described in their issuance prospectuses. Yet the capital structure remains unchanged. Going public increases the value of a company, but decreases its growth rate and profitability. The analyses confirm the hypotheses that companies go public mainly for opportunist reasons and use this opportunity to implement their investment plans.