Retail sales growth stalled in June, leaving merchants wondering whether shoppers who were resilient for much of the year are now curbing their spending because of higher gas prices.

As the nation's retailers began reporting their monthly sales early Thursday, disappointments included Wal-Mart Stores Inc. (WMT), Costco Wholesale Corp. (COST) and Limited Brands Inc. (LTD). Retailers who reported solid sales included Bebe Stores Inc. (BEBE) and Children's Place Retail Stores Inc.

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"It's a mixed bag, but it is definitely slower," said Jharonne Martis, an analyst at Thomson Financial. "Consumers' discretionary spending is decreasing as the economy is slowing down."

According to Thomson Financial's tally of same-store sales, which measure sales at stores open at least a year, 11 retailers beat estimates,while another 11 missed. Results at two merchants met expectations. Same-store sales are considered a key measure of a retailer's health.

June — the second most important month of the year in a retailer's calendar behind December_ is the period when merchants start to clear out summer goods to make room for fall merchandise.

Stores had some big challenges in June. Rainy weather, particularly in the Northeast, made selling summer clothes difficult. Results were also hurt by difficult comparisons with June 2005, when the same-store sales tally was the strongest in a year, helped by warm weather.

But analysts believe consumers are starting to feel the effects of increasing economic pressures including higher gasoline prices and interest rates. Higher rates have also helped cool the housing market. Last week, the Federal Reserve raised short-term rates to the highest point in more than five years but also lifted hopes that a respite from two years of increases might be in the offing.

Stores have feared a slowdown in consumer spending in the second half, but the question is how deep and when will it start.

Wal-Mart, the world's largest retailer, had a same-store sales increase of 1.2 percent, below the estimates of analysts surveyed by Thomson Financial; they predicted a gain of 2 percent.

Costco reported same-store sales increase of 6 percent. Analysts expected a 6.9 percent gain.

Limited reported a 3 percent increase in same-store sales, below the 5.1 percent analyst estimate.

At Children's Place, same-stores sales rose 14 percent, better than the 10.8 percent projected by Wall Street.

Teen retailers, whose results had rebounded in recent months, had mixed results. Bebe Stores Inc. posted a 3.5 percent gain for June, matching Wall Street estimates. But Pacific Sunwear of California Inc. suffered a 2.7 percent drop in same-store sales, less than the 0.5 percent decline expected.

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