This study analyzes export specialization and market-share dynamics among ten selected olive oil exporting countries during 2005-2023 using the Revealed Comparative Advantage (RCA) index and Constant Market Share (CMS) analysis. Drawing on ITC Trade Map data for HS 1509, it compares six Mediterranean producers with four New World exporters. To capture changes over time, the CMS decomposition is applied across five successive three-year transition windows. The results reveal a clear divergence between structural specialization and market-share performance. Tunisia records the highest specialization in the sample (RCA = 75.67) but a negative overall CMS residual share (-36.5%). By contrast, Portugal shows the most sustained improvement, with RCA rising from 6.50 to 18.02 and about 89.0% of export growth associated with positive residual gains. Chile emerges as the most dynamic New World producer, increasing its RCA from 0.15 to 1.01 and reaching a CMS residual share of 97.9%. Overall, the findings show that high export specialization does not automatically translate into sustained market-share gains.
