WASHINGTON—The U.S. government’s budget deficit widened in the first half of its fiscal year as spending rose faster than revenue compared with the first six months of fiscal 2017.

The deficit, or the difference between the amount of money the government spent and what it took in, stood at $599.71 billion in October through March, the Treasury Department said Wednesday. That was 14% higher than the deficit during the same period a year earlier. The federal fiscal year ends Sept. 30.

Wednesday’s report showed the federal budget deficit was $208.74 billion in March, up 18% from the same month a year earlier. Government revenue fell 3% in March compared with a year earlier, while spending grew 7%.

The revenue drop may reflect the package of corporate and individual tax cuts that Congress enacted in late 2017. In March, revenue from individual tax withholding dropped 2% from a year earlier, and gross corporate tax revenue dropped 41% from March 2017.

“We’re starting to see declines in individual income tax withholdings that reflect the adjustments to withholding tables,” said Nancy Vanden Houten, senior economist at research firm Oxford Economics. “It’s in the last two months that the effects of the tax cuts are starting to be seen.”