By John S. McClenahen It was the kind of day that gives the stock market multiple reasons to tumble. Retail sales in April fell 0.5% to $331.8 billion, the U.S. Commerce Department reported on May 13. Major factor: a nearly 2% drop in auto sales. Meanwhile, the U.S. Labor Department was reporting that initial claims for unemployment insurance rose by 13,000 last week to 331,000, following several weeks of downward movement. And the Labor Department reported that the Producer Price Index (PPI) for finished goods soared 0.7% in April, with both food and energy prices last month rising about 1.5%. UBS Investment Research, New York, notes that the year-over-year trend in non-food and non-energy finished goods prices advanced to 1.5% in April, the highest in nearly three years. "Commodity prices would have to fall much further to stem upward pressure on finished goods from earlier increases and growing pricing power," observes UBS. And it points out that prices of one very important commodity, oil, continue to rise. As a result, "the PPI should remain an unsettling omen of potentially higher consumer inflation" for Chairman Alan Greenspan and his 11 colleagues on the interest-rate-setting Federal Open Market Committee, says UBS.