The top 5 percent of consumers account for more than 37 percent of all consumer outlays, according to economist Mark Zandi. Increasingly, the wealthy are the only ones with money to spend, so they have an especially outsized influence.
The rich have both the money and the confidence to spend. A BMO Private Bank study of American millionaires (those with investible assets of $1 million or more) shows that 61 percent say they are better off today than they were before the recession. Only 7 percent say they are worse off.
(Read more: What gives? Millionaire optimism soars to new high)
The study also found that the wealthy are quickly returning to precrisis spending levels. Fully 86 percent are back to peak spending on entertainment and leisure activities, while spending on travel has rebounded for 83 percent. More than three-quarters are spending again on clothing and accessories.
"This represents an indication of the level of confidence they have in the country and also helps spur further economic growth," said Terry Jenkins, president and CEO of BMO Private Bank.