The Leading Economic Index slipped 0.1 percent to 94.7 following three consecutive months of increases. In January and February, the index rose 0.5 percent. In December it rose 0.4 percent.
The leading index compares current business activity with 2004, the year the Conference Board assigned a level of 100.
"Data for March reflect an economy that has lost some steam. In addition to headwinds from government spending cuts, the private sector economy may struggle to maintain its momentum. The biggest challenge remains weak demand, due to nervous consumer sentiment and slow income growth," said Conference Board Economist Ken Goldstein in a statement.
"Meanwhile," he said, "the coincident economic index (which measures current conditions) is down since December due to a large decline in personal income," he said.
The coincident index also dropped 0.1 percent in the month to 105.2.
That index also uses 2004 as a base point for comparison, assigning that year a value of 100.