• Online expansion helps drive fastest sales growth in two years
  • Zara owner plans to make inventory management more efficient

Tech-savvy retailer Inditex SA, whose online sales have put it ahead of its European clothing rivals, is trying to widen the gap further.

The owner of the Zara chain plans to expand its online offering to new markets and upgrade its inventory management technology. The moves are aimed at securing the Spanish company’s fast-fashion lead over rivals like Hennes & Mauritz AB of Sweden after the fastest earnings growth in almost two years.

“Inditex is one of very few non-food retailers that find themselves well-adapted for the online world,” wrote Anne Critchlow, an analyst at Societe Generale.

Inditex so far has defied the gloom afflicting other European apparel retailers contending with sluggish domestic economies, the rise of e-commerce and a shift in consumer spending away from clothing. H&M has warned of price cuts to clear inventory, while U.K. apparel chains like Next Plc and New Look Retail Group Ltd. have struggled to align their offerings with changing consumer tastes.

Inditex has adopted one of the retail industry’s most advanced inventory-tracking systems across all Zara stores, it said Wednesday. Inditex’s Massimo Dutti office-wear chain has also started using so-called radio-frequency identification tags, which automatically track the location of individual garments and help prevent theft. The retailer plans to introduce the technology in other formats in coming months,…