Costco Wholesale Corp. (COST) saw its shares plummet by 5% during Monday's intraday trading session, as investors began to reassess the company's valuation. The significant drop comes amid growing concerns that the stock's recent strong performance may not be sustainable in the long term.

The sell-off appears to be triggered by investor sentiment that Costco's stock may be overvalued. One investor was quoted as saying, "This bubble won't last," referring to the company's stock price, which has consistently outperformed the broader market in recent years. The comment reflects a growing unease among some market participants about Costco's ability to maintain its growth trajectory and justify its current valuation.

While Costco has been a favorite among investors due to its unique business model and consistent performance, the sudden drop suggests that the market may be reevaluating the company's long-term prospects. As the debate over Costco's valuation continues, investors will likely be closely watching for any signs of changes in the company's fundamentals or market position that could justify its current stock price.