Some of the enterprises providing messenger services in Budapest radically decreased their involvement in hidden economy in Summer 2006 which provides for a unique opportunity to study the dynamics of private decisions concerning tax evasion and hidden employment. Through interviews with CEOs of major companies on the market and a few of their employees, the study focuses on from which motivations, according to what conditions and based on which strategies did the enterprises change their tax paying behaviour. Furthermore, the success and downsides of such strategies were examined. According to the results, the key ingredients for changing the involvement in hidden economy are: the moral costs of the CEO stemming from illegal tax paying practices, the subjective appraisal of operating in the hidden economy. Nevertheless, these factors can only lead to alterations in the degree of tax evasion if the financial situation, market position of the enterprise, and its relations towards costumers and employees can provide a solid basis for covering the additional costs of fulfilling all legal obligations. These factors, in turn, determine the slices of these extra costs each involved actor has to bear. The main findigs suggest, firstly, that governments can successfully fight hidden economy through targeted state intervention on certain points of the cost-benefit relations in hidden economy. Secondly, decreasing asministrative burden of enterprises and clear communication of regulatory intentions motivate economic actors to reveal their hidden economic activity. Lastly, tax amnesties entail relatively low long-run costs in an economic environment where following norms is not well established.