Share capital of stock corporations is a monetary value whose equivalent shareholders are obliged to contribute to a company, and which cannot be paid back by a company to shareholders throughout its duration. Share capital exercises three functions: legal, economic and security-enforcing. From a traditional perspective the security (guarantee) function is the most important and it entails that share capital constitutes a guarantee of protecting a company's creditors. In the literature, however, the ability of share capital to perform this function has been more and more often undermined and consequently proposals are put forward to resign from the construction of share capital. The decision to reform share capital of a limited liability company in Polish law, too, seems already to have been decided upon. It is, however, unacceptable to completely resign from the protection of creditors' interests since the law must provide protection for weaker participants of trading such as small entrepreneurs in relation to stock companies. A serious alternative to share capital, however, seems to be the protection of creditors through the so-called solvency test, which subjects the payments for the benefit of shareholders to the condition that a company's assets at least balance its liabilities after such a payment. The protection of creditors based on the solvency test is not, however, free from faults. If the construction of share capital was to be resigned from and the solvency test was to be adopted to serve the function of a means of protecting creditors, it seems necessary to develop a characteristic buffer which would prevent using the construction of a limited liability company in high risk ventures and shifting a considerable amount of this risk on to the company's business partners, not to mention defending against making use of it for common fraud. The role of such a buffer might be played by an obligatory reserve capital based on the German UG model or the institution of obligatory transformation of a non-stock corporation into a traditional stock corporation with a share capital once it reaches a certain turnover in a prescribed period of time.