Retail giants Target (NYSE: TGT) and Walmart (NYSE: WMT) released first-quarter earnings last week, and what their investors saw in the reports led the markets into a further nosedive. Disillusioned investors are letting the disappointing results influence their view of Costco Wholesale (NASDAQ: COST), sending its stock price down about 13% last week as well. So investors already have a clue about how Costco is managing the same inflation, supply chain problems, and other macroeconomic factors as the rest of the retail sector.