Section: Articles Title: On the optimality of linear residual risk sharing / Jiajie Yang and Wei WeiAuthor: Yang, Jiajie Notes: Sumario: This paper investigates optimal risk-sharing in peer-to-peer insurance. Using total variance minimization as the objective, the authors show that the optimal allocation is linear but must be applied to residual risks rather than to original risks, improving efficiency and robustness relative to classical linear models. The study further incorporates market-motivated constraintssuch as variance reduction and retention consistencyand demonstrates that the residual linear structure remains optimal under these requirements. The resulting strategies promote fairness, participation incentives, and sustainability. Several related optimization problems are unified within this framework, and empirical case studies illustrate the practical advantages of the proposed residual risk-sharing model.Related records: En: Astin bulletin. - Belgium : ASTIN and AFIR Sections of the International Actuarial Association = ISSN 0515-0361. - 15/09/2025 Volume 55 Issue 3 - September 2025 , p. 514 - 536Materia / lugar / evento: Distribución de riesgos Seguros P2P Mercado de seguros Cálculo actuarial Modelos matemáticos Matemática del seguro Equidad actuarial Otros autores: Wei, Wei International Actuarial Association Other categories: 6 Rights: In Copyright (InC) See issue detail