Corporate or external streamers?—The dynamic impact of different types of streamers on product sales

In the rapidly expanding live-streaming e-commerce environment, firms struggle with inefficient streamer allocation because the dynamic, time-varying effects of different streamer types remain unresolved. This study investigates how the sales-boosting effects of corporate versus external streamers evolve over time and across product types. Utilizing a Generalized Additive Model (GAM) on a robust 53-week longitudinal dataset tracking 944 top-selling products (47,733 observations) on Douyin, we capture nonlinear temporal dynamics. The empirical results reveal highly significant time-varying trajectories: the sales impact of corporate streamers exhibits a sustainable, gradually strengthening trend, whereas external streamers’ impact significantly decays after an initial spike. Furthermore, product type dynamically moderates these trajectories. The sustainable advantage of corporate streamers is significantly amplified for search goods, while the rapid decay of external streamers’ effectiveness is pronounced for experience goods. To unpack the psychological mechanism driving these macro-level dynamics, a controlled behavioral experiment (N = 200) demonstrates that corporate streamers foster cumulative purchase intentions via cognitive trust, whereas external streamers rely on transient affective trust. Ultimately, this research shifts the streamers marketing paradigm from a static to a dynamic perspective, providing firms with evidence-based guidance for tailoring streamer selection to product types and campaign stages to achieve sustainable sales growth.