Debt instruments have an important place in meeting the financing needs of joint stock companies. In order to encourage investors to invest in these instruments, there are a series of legal requirements and regulations to protect investors in the entire process from the decision to issue these instruments to the operation and completion of the relevant procedure. In this context, our study first focuses on debt instruments in general, the authorisation and scope of issuance. Afterwards, the importance of protecting the investors of debt instruments is emphasised and the liability regulations arising from the public disclosure documents are discussed in detail. In the sequel of our study, debt instruments are analysed within the framework of the risk of deterioration of the financial situation of the issuer, the lapsing into default, liquidation regulations and systems and funds for indemnification of investors. Out-of-court remedies are also included in our study and finally, the study concludes by analysing the possibility of contingent capital increase.