NEW YORK — Shoppers are still showing some scars from the recession. In a May filled with wild stock market swings, consumers gave retailers only slim revenue gains over a terrible May 2009.

The second straight month of sluggishness after a surprisingly solid start to the year underscores both the fragility and choppiness of the economic recovery that will most likely persist at least through the fall.

The International Council of Shopping Centers index for revenue at stores open at least a year reflected such tentative spending, rising 2.6 percent in May. The figure was in line with a reduced growth forecast that ranged anywhere from 2 percent to 2.5 percent.

Michael P. Niemira, ICSC's chief economist, had originally expected a 3.5 percent gain. May's results follow a 0.8 percent gain in April, and a 9.0 percent increase in March.

"It's going to be a roller coaster," said Sherif Mityas, a partner in the retail practice at management consultant A.T. Kearney. "You're going to have fits and starts. ... Consumers are looking for threads of good news among the bad news, and that's dictating what they're spending on everything from groceries to $1,000 TVs."

Mityas said he doesn't believe a recovery will be in full swing until the fourth quarter.

The choppy stock market hasn't made consumers who'd started to spend again any more confident.

"We've had our splurges. We don't need to waste any more money," said Stacy Phillips, 46, who lives in Brooklyn with her husband, a chief financial officer for an HMO.

They spent $4,000 on a vacation to Iceland and Paris in early April, but now they're feeling frugal again as they worry about the stock market, which has tumbled on fears that a European debt crisis will hammer global economic growth.

"It doesn't seem like anything is happening that's making me feel better," she added.

A mix of stores found business challenging during the month.

Target Corp.'s chairman, president and CEO, Gregg Steinhafel, noted in a statement the discounter expects to continue to "experience volatility in the pace of economic recovery." The chain posted a small gain that was below internal forecasts.

Department store chain J.C. Penney and many teen merchants including Abercrombie & Fitch Co. and American Eagle Outfitters Inc. reported declines in revenue at stores open at least a year.

Costco Wholesale Corp. reported a gain slightly below Wall Street expectations. Gap Inc. posted a small gain overall, but its namesake chain in the U.S. saw revenue decline.

Among the bright spots were Victoria's Secret parent Limited Brands Inc. and T.J. Maxx parent TJX Cos., both of which reported bigger-than-expected increases.

Revenue at stores open at least a year is a key indicator of a retailer's health.

Another report from Mastercard Advisors' SpendingPulse showed shoppers took a pause as they cut back on almost everything from appliances to shoes and clothing at the mall.

SpendingPulse measures spending in all forms including cash from May 2 through Saturday.

Cool weather and a quirk in the calendar — a late Memorial Day weekend that hurt May's business but should boost June's figures — didn't help.

But weakness in the past six weeks is due to more than weather and calendar flukes, analysts said. They cited high unemployment that's stuck at almost 10 percent, stock market jitters and the dwindling of government-funded rebates on energy-efficient appliances.