What Americans are doing with their gas pump savings

Although consumers have gotten a windfall estimated at about $1,000 per household over the past year, thanks to the 40 percent drop in gasoline prices, they're keeping a tight grip on their good fortunes.

A recent survey by Visa (V) found that half of respondents plan to sock away their gas pump savings. This trend was also borne out by data released today by the U.S. Commerce Department that found the savings rate in December rose to 4.9 percent, from 4.3 percent.

"Consumers appear to be saving most of their recent windfall from lower gasoline prices," said Gus Faucher, a senior economist with PNC Financial Services Group, in a note.

Saving more may be prudent because many Americans, having only recently emerged from the worst economic slowdown since the Great Depression, are worried about getting burned again by living beyond their means.

"Unemployment is lower, maybe people are finally able to make ends meet and so they do not have to borrow," wrote Sharmilla Chaterjee, senior lecturer at the MIT Sloan School of Management, in an email. "Many are paying more out-of-pocket healthcare costs. Wage stagnation does not help, though lower gasoline prices are good news for middle and lower income Americans."

The drop in gasoline prices picked up steam in recent months, but it isn't large enough to make a difference in the budget of most Americans, according to Matthew J. Slaughter, a professor at Dartmouth College's Tuck School of Business.

"A lot of people didn't predict this drop, and it's hard to know where it will go in 2015," he said. Gasoline prices finally rose last week after falling for a record 123 consecutive days, according to AAA.

Of course, saving more money is a good thing. Experts have complained for years that Americans save far too little. Only 14 percent of those surveyed by Bankrate in November listed putting aside money for a rainy day as their top financial priority. A separate poll released last year by Gallup found that 59 percent of Americans said they were worried about not having enough money for retirement, ranking it the No. 1 concern.

Nonetheless, economic growth is closely tied to consumer spending and is closely watched on Wall Street. Investors may become worried by signs the public isn't in the mood to buy. Consumers' reluctance to spend was evident in the recent disappointing December retail sales report that showed a 0.9 percent decline (many economists expect it will be revised upward, which often happens with this data).

"In December, consumers pulled back after splurging in November," wrote Chris Christopher of IHS Global Insight in a note to clients. "Spending gains in November were driven by strong auto sales, robust holiday shopping, and early and deep price discounting. When December rolled around, most households decided they needed to take a breather, but were still enjoying falling gasoline prices."

Even wealthier consumers kept their spending in check. Luxury retailer Tiffany (TIF) reported disappointing holiday results. The parent company of Gucci recently recorded its slowest sales growth in four years amid a slowdown in Europe and Asia.

Economists caution against reading too much pessimism into the data because the overall economic picture continues to be positive. Unemployment is a 5.6 percent, the lowest rate since 2008. Consumer sentiment measured by the closely followed University of Michigan index hasn't been this high since 2004. Personal income jumped 0.3 percent in December, while consumer spending showed gains in both the fourth quarter and for 2014 as a whole.

Of course, as every investor should know, past performance doesn't guarantee future returns.

"There is a great deal of uncertainty [among economists] over what kind of growth we should expect in the future," said Nikolai Roussanov, associate professor of finance at the University of Pennsylvania's Wharton School of Business.