The impact of delayed retirement on the financial sustainability of China's urban employee pension insurance fund.

Against the backdrop of accelerating population aging and mounting concerns over the financial viability of public pension systems, this paper develops an actuarial simulation framework that integrates demographic dynamics, fund revenue and expenditure rules, and the central adjustment mechanism. We evaluate four scenarios: baseline, delayed retirement only, national pooling only, and the combined reform. Our findings indicate that in the absence of policy intervention, regional disparities in fund balances intensify markedly: the western region enters cumulative deficit first, followed by the central region, while the eastern region retains a longer but still finite reserve buffer. The delayed-retirement-only path does not by itself improve fiscal performance in the present calibration, whereas national pooling narrows current deficits and postpones reserve depletion in deficit regions. When the two reforms are implemented jointly, the combined scenario delivers the strongest overall performance and produces a positive interaction effect on both current and cumulative balances across all three regions. Sensitivity tests further show that pessimistic macro conditions, weaker collection, and lower fund return materially erode the gains, while province-level results reveal substantial heterogeneity within each region. To strengthen the long-run sustainability and institutional resilience of the urban employee pension insurance system, we recommend refining the design of the national pooling mechanism, advancing delayed retirement together with complementary labor-market measures, and adopting regionally differentiated implementation and dynamic adjustment.