Based on the latest data from August 2025, Costco (COST) is trading at $943.32 with the stock positioned between the 31.9x and 37.6x PE multiples. The current price sits above the lowest PE boundary of $562.99 (31.9 times) but below the second PE boundary of $665.09 (37.6 times), indicating the stock is trading in the "Value" zone. This suggests that while the stock has moved beyond severely undervalued levels, it still presents reasonable investment value at current PE ratios. Analyzing the historical trend, Costco's valuation has experienced significant expansion over the five-year period. The stock began 2020 trading near the 31.9x PE boundary around $270, representing undervalued territory. A notable valuation expansion occurred throughout 2021-2022, with the stock breaking above multiple PE bands and reaching the 43.4x-49.2x PE range (Fair to Watch zones) by mid-2022 when prices peaked near $554. The most dramatic valuation expansion occurred in 2024-2025, where the stock surged from around $624 in late 2023 to over $1,043 by February 2025, briefly touching the upper PE boundaries. However, the recent pullback to $943 has brought the stock back into more reasonable valuation territory. The overall trend shows the PE river boundaries have been steadily rising, indicating consistent earnings growth, while the stock price has generally tracked above the lower PE multiples, suggesting sustained investor confidence in the company's premium valuation.