Novelty and Impact (max. 75 words):Switzerland has universal health insurance coverage, high health expenditures, and one of the highest life expectancies in the world. Despite that, this study describes high-risk groups for later-stage breast cancer (BC) diagnosis and higher BC specific mortality in Switzerland. Women of lower socioeconomic position were more likely to present with later-stage BC and showed poorer disease-specific survival. Notably, survival inequalities could not be explained by socioeconomic differences in stage at presentation and/or other sociodemographic factors. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record.