Thomson Reuters
A shopper looks at grocery items at a Target store in Los Angeles
The consumer sentiment index fell to 96.9 in the final March survey.
Economists had forecast the index would hold steady from the preliminary reading of 97.6.
Various measures of consumer confidence have jumped since the US presidential election in November.
And in a longer-term view, the UMich index remains strong as respondents remain optimistic about higher incomes and wealth, more favorable job prospects, and low inflation expectations.
However, details beneath the headline indices show that Americans are deeply divided about the new administration and the country's economic future.
"Democrats expect an imminent recession, higher unemployment, lower income gains, and more rapid inflation, while Republicans anticipate a new era of robust growth in incomes, job prospects, and lower inflation," said Richard Curtin, the survey's chief economist.
"It is a rare situation that combines increasing optimism, which promotes spending, and rising uncertainty which makes consumers more cautious spenders."