U.S. GDP growth in the second quarter is expected to come in significantly below first quarter growth, as the impact of the Tax Cut and Jobs Act fades.

The big picture: It would be the weakest quarter of U.S. growth since Q4 2015.

This year's Q2 growth is also expected to show far less inventory investment than Q1, which got a boost of 0.65% from a $46.3 billion inventory buildup by U.S. firms. Government spending was seen as slower in Q2.

Last year's second quarter also showed significant growth, rising 4.2% year-over-year, which was the strongest quarter in nearly 4 years.

Go deeper: The global push to reinvent GDP