The barometer of current economic conditions fell to 99.8 in May from 107 in April.
The gauge of consumer expectations dropped to 81.5 from 88.8 in the previous month.
Americans expect the inflation rate in the next year will be 2.9 percent, compared with 2.6 percent in April. Over the next 5 to 10 years, they expect consumer prices to accelerate to 2.8 percent, compared with 2.6 percent in April.