The study of domestic money goes at the heart of debates about independence and equality in intimate relationships. It provides an important window on the individualization of family life and how couples reconcile ideals around egalitarian marriage ideologies with enduring gender inequality in society and the labor market. This study approaches these issues from the prism of couples' banking arrangements (separate vs. joint accounts), an aspect of financial organization that approximates the executive management of household resources and which has received comparatively little attention. As such, it is amongst the first to deploy large-scale, household panel data (Household, Income and Labour Dynamics in Australia Survey, n = 15,379 observations from 7,054 couples) and binary and multinomial random-effect logistic regression models to examine trends over time in couples' banking arrangements and their socio-demographic predictors. Key findings indicate that a large share of couples in Australia favors 'mixed' bank account strategies (i.e., holding both joint and separate accounts), but 'egalitarian' choices (i.e., dual separate accounts) are prevalent and on the rise. Couples' bank account choices are influenced in theoretically-meaningful ways by economic resources, transaction costs, relationship history, gender-role attitudes, and family background.