INTRODUCTION: Young-onset dementia is often diagnosed late, leaving gaps in understanding its impact on employment, income, and social security. METHODS: Analyzing health insurance claims and medical records, we studied 16,010 young-onset dementia cases and 129,616 matched controls. Using a non-parametric event study, we assessed earnings, earnings plus benefits, employment losses, and benefit use, considering demographic and socio-economic factors. RESULTS: Earnings fell by 58.7% in the years prior to dementia identification, totaling €144,013 in losses, and earnings plus benefits decreased by 20.7% (€68,533). We observed a 35.5 percentage point decrease in employment, a 23.9 percentage point increase in disability insurance, and a 2.7 percentage point rise in welfare benefit use. Primary education and lack of a partner correlated with higher earning losses and lower disability insurance uptake. DISCUSSION: Early diagnosis and robust social support systems are vital to alleviate the financial and professional challenges faced by individuals with dementia under age 65. HIGHLIGHTS: Working-age persons experience job loss at least 21 years before dementia identification. Job loss is linked to 59% (€16,643) earnings drop 16 years before dementia identification. Losses in earning were not fully compensated by social insurance. A generous social insurance system eases the financial impact of young-onset dementia. Attention is needed in the work environment and on disability benefit decisions.