Washington ? The rebuilding of Americans’ wealth is proceeding in steps rather than strides.

Households’ net worth rose last quarter — the fourth straight quarterly gain. Yet tumbling stock prices have reduced their wealth since then. Some economists say Americans’ net worth may now be down slightly for the year. That helps explain why many say it will 2012 or 2013, at best, before Americans’ wealth will return to its pre-recession levels.

Net worth — the value of assets like homes, bank accounts and investments, minus debts like mortgages and credit cards — rose 2.1 percent last quarter, the Federal Reserve said Thursday. It now amounts to $54.6 trillion.

In the midst of the recession, household net worth sank as low as $48.3 trillion. It’s since risen 13 percent. Yet even counting last quarter’s gain, net worth would have to rise 21 percent more to regain its pre-recession peak of $65.9 trillion.

Household wealth is vital to the economy because consumers tend to spend according to how wealthy they feel. And their spending accounts for about 70 percent of the economy.

During the recession, sinking home equity and stock prices made shoppers skittish. If they become more nervous about their finances, the economic rebound could weaken or stall.

Over the past several quarters, the growth of net worth has been uneven. Last quarter’s 2.1 percent increase exceeded the 0.9 percent increase in the fourth quarter of last year. But it fell well short of the 4.1 percent rise in the second quarter of 2009 and the 5.4 percent gain in the third quarter.

As Americans have gradually recovered some of their wealth, many of them — especially the affluent — have been spending more. But the housing and stock markets remain fragile. That’s why most consumers aren’t spending as freely as they typically do in the early phases of recoveries.