The upgrade in price target by a reputable analyst like Paul Lejuez from Citigroup is a strong positive signal for Ross Stores. It suggests a bullish outlook on the stock's future performance, likely due to underlying strengths in the company's business model, market position, or financial health. This kind of endorsement can significantly influence investor sentiment and potentially lead to a short-term increase in stock price as market participants adjust their valuations based on the new price target.