Fast, stable, or credible? Mobile experience outcomes in certified luxury retail

Mobile interactions increasingly shape how consumers judge luxury brands, yet it remains unclear whether sustainable-certified brands deliver mobile experiences consistent with the elevated execution expectations implied by ethical signaling. Drawing on a signaling theory and expectation-based perspectives, this paper conceptualizes mobile UX performance as an execution-level signal through which certification credibility is reinforced or undermined. Using real-user PageSpeed Insights field data for 133 Butterfly Mark certified luxury brands, the analysis benchmarks Core Web Vitals and models Google’s “Fast” mobile classification as a function of loading speed and visual stability. The findings reveal an asymmetric structure of digital performance signals: visual stability operates primarily as a baseline hygiene condition, with most brands meeting recommended thresholds and no robust sector-level differences, whereas loading speed, measured by Largest Contentful Paint, emerges as the dominant predictor of platform-defined mobile experience quality. Even modest reductions in loading time substantially increase the probability of achieving a “Fast” classification, while additional gains in stability yield diminishing returns once baseline standards are satisfied. The study advances marketing analytics research by demonstrating how platform-generated technical metrics can be modeled by showing that sustainability certification functions as an expectation amplifier.