Impulse buying is a phenomenon in which consumers make unplanned purchases, generally motivated by emotions rather than rational decision-making (Iyer et al., 2020; J. Zhang et al., 2022). This behavior is especially common in the fast fashion business, where new trends emerge quickly and products are frequently presented as limited-time offerings to instill a sense of urgency. Marketers regularly use perceived scarcity messaging, such as "limited quantity scarcity" (LQS) and "limited time scarcity" (LTS), to capitalise on consumers' fear of missing out (FoMO), resulting in impulse purchases (Cengiz & Şenel, 2023; Zhang et al., 2022; Zhang et al., 2021) .In Indonesia, the fast fashion industry has seen significant growth 80% from 2019 to 2024 (Statista Market Insight, 2024), driven by an increasingly young and digitally connected population. The proliferation of e-commerce platforms and social media has further amplified the reach of fast fashion brands, making it easier for consumers to access the latest trends and deals. As a result, Indonesian consumers are constantly exposed to various marketing strategies that promote impulse buying, including perceived scarcity messages.

Keywords: Percevied scarcity messages, FoMO, impulse buying, influencer role, gen-z.