Industry stalwarts Wal-mart Stores Inc. and Sears, Roebuck & Co. are among retailers who have warned Wall Street analysts over the past few days that their first-quarter earnings won't meet expectations. Their announcements come as the Commerce Department says overall retail sales in March dipped 0.2% from February, which itself was a lackluster month.

Retail sales trends are important to retail-property owners for several reasons, including the fact that rent paid by a tenant is often partially based on its gross sales. A good sales month can put extra cash in the property owner's coffers, but a poor one sinks right down to the owner's bottom line.

"We were expecting a very weak March, but it turned out to be one of the weakest months in 25 years," says Kurt Barnard, president of New Jersey-based Barnard's Retail Consulting Group and publisher of a newsletter that tracks industry trends. "It was really a very, very poor performance on the part of most retailers."

Barnard and other experts say several factors are contributing to the disappointing sales figures. Those include unusually nasty spring weather that has plagued the Midwest and East Coast over the past several weeks, continuing uncertainty about the economy's future and wild stock-market gyrations that have left millions of individual investors with far less disposable income than they had just a few months ago.

Wal-mart and Sears weren't the only retailers to report bad news late last week. The parent of Saks Fifth Avenue said its same-store sales were down 6.9% from a year-earlier, while Neiman-Marcus Group Inc. reported a 4.7% drop.

Retailers based in Southern California fared better, but not by much. Pacific Sunwear says its sales declined a more modest 4.1%, while Wet Seal Inc. was one of the few to report a year-over-year sales gain—albeit a scant 0.8%. Both companies are based in SoCal and cater to teenage buyers, a group whose spending habits aren't influenced much by the murky economic outlook and troubles in the stock market.