IRS pushes filing deadline to May 17 as agency grapples with backlog of returns Lawmakers fear that long-unresolved troubles at the Internal Revenue Service could undercut the Biden administration’s new economic recovery efforts. By Tony Romm and Jeff SteinThe Washington Post Share WASHINGTON — The Internal Revenue Service announced on Wednesday it is postponing the country’s tax-filing deadline until May 17, as the agency grapples with a mounting backlog of 24 million returns awaiting processing since the 2019 tax year. The workload has put the agency underwater – and under political siege – as lawmakers fret that long-unresolved troubles at the IRS could undercut the Biden administration’s economic recovery efforts. Millions of Americans have not received some stimulus checks under prior coronavirus aid packages, even as the tax agency continued distributing payments Wednesday under the $1.9 trillion stimulus signed into law this month.