Zara has had a charmed run these last few years, and most analysts are expecting owner Inditex to report another quarter of robust sales growth on Dec. 11. The Spanish fast-fashion giant has built a seemingly impenetrable moat around its biggest brand. Wednesday’s results should be watched for clues about how it plans to maintain and expand those defenses.
Inditex’s success stems first and foremost from its ultra-efficient supply chain, which is designed to quickly produce limited runs of…

