The Protecting Americans from Tax Hikes Act (PATH Act) prevents the IRS from issuing early refunds on any tax return that claims the Earned Income Tax Credit (EIC) and/or Additional Child Tax Credit.
Congress passed the PATH Act because identity thieves frequently claim one or both of these refundable tax credits. The PATH Act gives the IRS extra time to detect fraudulently-filed returns, which helps identity theft victims get their legitimate refunds more quickly.
The IRS usually begins issuing tax refunds on returns with the EIC or Additional Child Tax Credit in late March.
If your return contains either of these credits, you can track its status at the IRS Where's My Refund? site.