The University of Michigan's preliminary December consumer sentiment index reading was 74.5, compared to the final November 82.7, the preliminary November 84.9, and the final October 82.6, according to market sources.
The expectations index was 64.6, compared to 77.6 in November, 80.8 earlier in the month, and 79.0 in October.
The current conditions index was 89.9, compared to 90.7 in November, 91.3 earlier in the month, and 88.1 in October.
Economists polled by Thomson Reuters had predicted an 80.0 reading for the main index, 85.0 for current conditions and 75.0 for expectations.
The five-year inflation expectation index was 2.9%, compared to 2.8% in November, while the one-year inflation expectation index was 3.3%, compared to 3.1% in November.
The University of Michigan index is not released to the press, but only to paying subscribers.