As of the most recent data point on 2025-11-23 (Q1'26), Costco's PEG Ratio stands at -2.11. This value reflects a negative PEG ratio, which may indicate either negative expected earnings growth or other anomalies in the company's earnings projections. Over the period from Q3'23 to Q1'26, the PEG Ratio for Costco has exhibited significant volatility, fluctuating between highly positive and deeply negative values. Notably, there were sharp declines to -14.36 in Q3'24 and an extreme low of -134.74 in Q2'25, followed by a rapid rebound to 9.19 in Q3'25. This pattern suggests considerable uncertainty in growth expectations and earnings forecasts, with no clear sustained trend over the observed quarters.