Immigrants’ lives are measured and debated along many axes: language acquisition, neighborhood choice, and even family formation. But another overlooked form of assimilation persists. I use “financial assimilation” to capture noncitizens’ inclusion within American financial markets, for better or for worse. The law defines financial assimilation in different ways for different types of migrants. Federal law can tie migrant resettlement to private sponsorship—as Americans’ financial stature supports newcomers—or protect work-authorized noncitizens under financial antidiscrimination laws. Federal law can also deter, if not prohibit, financial assimilation when it limits lending in marquee markets like housing, even as state laws forge a different path. The law offers a far less glossy form of financial assimilation by conditioning detained immigrants’ freedom on financial bonds. Immigration law’s exclusive forces do not preempt financial assimilation. Beyond defining and describing financial assimilation, this Article uncovers its risks. Financial assimilation generates visibility, and therefore surveillance and immigration enforcement, especially as legal safeguards falter in markets for money transmission and carcerality. I argue that a safer future for financial assimilation is possible, even amid heightened immigration enforcement. Noncitizens and their financial transactions will endure.

This Article proposes reforms to better align tax agency efforts with their revenue-generating mission and to protect immigrants caught in the crosshairs. Those reforms include redesigning criminal tax investigations, crafting interagency agreements, and providing immigration relief.