Background and Objectives Impairment in financial management abilities, which we label “Acreemagnosia”, is an early symptom of older people experiencing cognitive decline. This article describes the development and psychometric evaluation of The Acreemagnosia Measurement (TAM) which assesses everyday financial abilities and could be applied to older people who are healthy, experiencing MCI, or affected by dementia. TAM is a multi-item scale combining subjective, objective and performance-based measures that assess abilities and awareness across a wide range of financial functions and tasks. Methods Item Response theory (IRT) was applied to examine the structure and item performance, as well as to determine scale reliability. Results Analysis suggests that TAM is measuring most reliably at low to average levels of financial ability which is appropriate for testing elderly retired people, experiencing MCI, or affected by dementia. All the items in TAM show a good discrimination capacity. Differential Item Functioning (DIF) analysis did not show any gender or age bias. Discussion TAM is a useful tool for the measurement of everyday financial abilities in older people.