Several psychological brand performance indicators that predict a brand’s intermediate market share have been identified. So far, rating studies have exclusively investigated brand effects in terms of linear relationships, and their specific and possibly nonlinear interactions have yet to be examined in comparison. Hence, we investigated the relative importance of three well-established psychological performance indicators, attitude toward the brand, perceived quality, and brand experience, in predicting brand loyalty. A sample of 1,077 participants completed an online survey and rated subsets of 105 international brands from various product and service industries. Relations between attitude, perceived quality, and experience in predicting loyalty toward a brand were analyzed using semi-parametric additive mixed regression models. We replicated that all three predictors significantly impacted brand loyalty and revealed a pronounced nonlinear relationship between attitude and loyalty. The inclusion of nonlinear interactions between predictors improved model fit. In particular, the nonlinear interaction between perceived quality and attitude substantially impacted brand loyalty. In addition, these effects differ by type of industry, specifically fast-moving consumer goods, automotive, fashion, electronics, and finance/insurance. These findings draw attention to nonlinear patterns between specific psychological features of brands. Future research should address nonlinear effects and the specific interactions of other essential predictors of brand equity.