Updated from 9:32 a.m. EDTU.S. retailers reported generally strong same-store sales for March, supporting analysts' perceptions that shoppers kept busy in the first quarter. Several companies also lifted earnings projections above Wall Street estimates. "The trend is quite positive," said Richard Keim, managing director at Kensington Management Group. "There were a few disappointments, but there were a bunch that were better than expected." Despite the good results, shares of most retailers were dropping in morning trading, an action Keim thinks is profit-taking after a hardy run-up in prices. Investors could also be focusing on the tough comparisons that materialize in the year's second half, Keim said. "You'll see a stabilization once world news gets a little better," said Keim. "Then, it will be off to the races. We're in a pause." Earlier Thursday, the world's largest retailer, Wal-Mart ( WMT), said March same-store sales rose 6%, which was at the high end of its guidance. Total sales rose 14% at $22.05 billion. The company's core Wal-Mart division had a 5.6% increase in monthly same-store sales while total sales increased 12.3% to $16.72 billion. The company's Sam's Club unit had a 8.3% rise in same-store sales with total sales up 9.3% to $3.38 billion. Wal-Mart said it sees April same-store sales up 4% to 6%, though because Easter is one week earlier this year, it expects results to come in at the low end of that range. The stock was trading down $1.03, or 1.8%, at $56.95. Target ( TGT) said same-store sales rose 7.3%, ahead of expectations, while total sales increased 13.2% to $4.4 billion. The company's core Target division had a 7.8% increase in same-store sales, while its department stores Mervyn's and Marshall Fields, which Target is in the process of selling, each had positive results: Mervyn's same-store sales rose 0.8% while Marshall Field's were up 9.9%.