LTReikšminiai žodžiai: Alfa-stabilus pasiskirstymas; Daugiapakopis stochastinis sveikųjų skaičių programavimas; Laiko nuoseklumas; Pensijų sistemos modeliavimas; SRV; Tikslinės datos lėšos; Alpha-stable distribution; CVaR; Multistage stochastic integer programming; Pension system modeling; Target date funds; Time consistency.
ENIn this paper we consider the problem of choosing the optimal pension fund in the second pillar of Lithuanian pension system by providing some guidelines to individuals with defined contribution pension plans. A multistage risk-averse stochastic optimization model is proposed that can be used to plan a long-term pension accrual under two different cases: minimum and maximum accumulation plans as possible options in the system. The investment strategy of personal savings is based on the optimal solutions over possible scenario realizations generated for a particular participant. The concept of the risk-averse decisionmaker is implemented by choosing the conditional value at risk as the risk measure defined by a nested formulation that guarantees the time consistency in the multistage model. The paper focuses on three important decision-making moments corresponding to the duration of periods to be modelled. The first period is a short-term accumulation, while the second period is a long-term accumulation with possibly high deviation of objective function value. The third period is designed to implement the concept of target date fund in the second pillar pension scheme as the subsequent need to protect against potential losses at risky pension funds. The experimental findings of this research provide insights for individuals as decisionmakers to select pension funds, as well as for policy-makers by revealing the vulnerability of pension system. [From the publication]