The article considers the pension system of the Republic of Kazakhstan as the most important element of the system of social protection of the population and a major investment player in the market, which is responsible for the safety of pension savings of the population. Consequently, it is necessary to constantly monitor the quality of pension provision and financial sustainability of the pension system in order to ensure the adequacy of pension payments to maintain a decent standard of living for pensioners, taking into account the inflation rate in the country. Thus, it is necessary to carefully assess the possible consequences of investment decisions in order to prevent the depreciation of pension system participants' savings. The pension system is an important element for ensuring the stability of the country's population. It forms the foundation of social security for citizens, creating financial security for them during the period of disability or retirement. Due to demographic changes in the country, the pension system is being reformed, which in turn affects financial stability in the Republic of Kazakhstan. The article presents a number of key roles and functions within the pension system, analyzes the volume of pension savings and the number of individual pension accounts in the cities of national importance, presents the structure of the investment portfolio of the PAs of the Unified Accumulative Pension Fund (UAPF), which are under the trust management of the NBRK, in the context of financial instruments. Proposals on how to increase investment income have been developed.