WASHINGTON — Americans are spending more of their growing wealth. The economy still needs companies to do the same.

Still lacking the confidence to spend at normal levels, businesses have stockpiled nearly $1.9 trillion in cash, a record, the government said Thursday.

Cash now accounts for 13 percent of corporate assets, the highest share since 1984. Economists say the surest way to reduce unemployment would be for companies to spend more of that cash to expand and hire.

The same report, based on data from the last three months of last year, showed households are further rebuilding the wealth they lost in the recession. Americans' net worth grew 3.8 percent, mostly thanks to the rising stock market.

Greater household wealth generally leads Americans to spend more. They increased their spending in the October-December quarter at the fastest pace since 2006.

Household net worth came to $56.8 trillion at the end of 2010, even though the value of real-estate holdings fell 1.6 percent, according to the Fed. Last quarter's gain was faster than the 2.6 percent gain in the previous quarter.

But companies are still waiting for signs that the economy and their own businesses are strengthening enough to justify spending aggressively again. Last year, many companies were concerned about the possibility of a second recession.

While high oil prices are still a concern, those recession fears are mostly gone. The economy is expected to grow faster this year as people spend more. Still, many businesses are cautious.

"We are sitting on more cash than we typically would," says Mike Dougherty, CEO of D&S Manufacturing in Black River Falls, Wis.

Dougherty says he's waiting to see "how economic conditions unfold" before deciding whether and how to use the company cash.

In recent months, D&S has added about 10 workers, increasing its staff to about 160. But, Dougherty says, "Times are a little bit uncertain, and having surplus cash is a good position to be in." Among his concerns: rising steel prices, which account for up to 40 percent of his costs.

The 13 biggest cash-hoarders among companies in the Standard & Poor's 500 had stockpiled more than $300 billion in cash by the end of last year, according to S&P analyst Howard Silverblatt. Among them: Cisco Systems with $40.2 billion cash on hand, Microsoft with nearly $40 billion and Google with nearly $35 billion.

In an Associated Press survey earlier this year, most economists said the step that would help bring down unemployment the most would be for corporations to spend more of their cash.

Economists say companies overall have spent more of their cash since 2011 began. But in many cases, the money has gone toward paying dividends and buying back the companies' own stock, not for hiring and expanding. The U.S. unemployment rate, now at 8.9 percent, is expected to fall only slightly further this year.

"Cash is a good security blanket in uncertain times," says Lynn Reaser, chief economist at Point Loma Nazarene University in San Diego. "But I think we'll see the cash cushion go down a little bit this year because there is greater certainty now about the staying power of the economic recovery."

Americans' net worth would have to rise an additional 16 percent to reach its pre-recession peak of $66 trillion. But it's well above the low of $49 trillion in early 2009, during the recession.

In the final three months of last year, the value of households' stock portfolios reached $8.5 trillion. That was a 12.3 percent increase over the prior three months.

The S&P 500 index, a broad gauge of the market's performance, soared 22 percent in the second half of last year.

The vast majority of people who have 401(k) retirement savings accounts now have more money in their accounts than at the market peak in October 2007, according to estimates by Jack VanDerhei of the Employee Benefit Research Institute in Washington. While the market is still well below its peak, most people have kept putting money in those accounts.

People are also steadily reducing debt. Overall household debt dipped to $13.36 trillion in the fourth quarter, a 4 percent drop from the peak in 2008. The average household owes $42,951 — mortgages, credit cards, auto loans and other debt.

For most Americans, their home, not stocks, is their biggest asset, and the housing market remains depressed in much of the country. And even though stock market gains have brought back stock portfolios and retirement savings, higher prices for food, gasoline, health care and other things are putting the squeeze on some people.