About 5.8 million custodial parents were owed child support but just 2.5 million received it in full in 2015, according to a comprehensive Census survey that was re-released this year and provides the best available data, which experts say is unlikely to have change much.
That leaves 3.3 million who are overdue. Not all will qualify for money — income thresholds max out at $99,000 for an individual or $198,000 for a married couple — but many who are otherwise eligible and might be desperate for cash will see their payments intercepted.
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Many will lose the money entirely. Non-custodial payments overdue on child support owe an average of $21,000, according to a December 2019 government report.
Owing back taxes or student loan debt won't be a problem for those seeking stimulus checks, but past due child support will be penalized as long as the information is properly reported by states to the Treasury Department. Once the payment is intercepted, the department is tasked with facilitating the transfer of the money to the entitled custodial parent.
Under a federal program, state child support agencies share information with the Treasury Department on who is behind on obligations so the agency can snatch the money from income tax rebates or other payments.
The U.S. government also tries to force child support payments in other ways, such as denying passports to delinquent parents who owe more than $2,500.
Ryan Ellis, a lobbyist and expert on tax policy, said the 3.3 million figure of those who are delinquent probably hasn't changed much since the Census survey, which reflects the best available data on the matter.
"Large social indicators like this change over time, but not quickly," he said. "A data study from a few years ago is a pretty reliable snapshot of where the numbers are today."