Who really moves the market? Unveiling the power of social media influencers in investor decision-making

Purpose In the digital era, social media influencers act as informal advisors, shaping investor behaviour. Their opinions often drive market movements, especially among retail investors and younger demographics. This study aims to identify and prioritize the types of social media influencers based on their impact on investor decisions, while examining the interrelationships among key determinants to assess their influence. Design/methodology/approach This study, conducted through an extensive literature review, examines the key determinants of the influence of social media influencers and their various types. The study first investigates the interrelationship between key determinants to assess the influence of social media influencers, using the Fuzzy DEMATEL method. It prioritizes social media influencers based on their influence on investor decisions using Fuzzy TOPSIS. Findings According to the Fuzzy DEMATEL results, Relevance and Market Fit, as well as Risk Awareness and Decision Impact, are the key determinants for assessing the influence of social media influencers, as these determinants originate from the cause group. Based on the closeness index values calculated through Fuzzy TOPSIS, Key Opinion Leaders are identified as the most influential type of social media influencers, followed by YouTubers. Research limitations/implications This study advances the existing literature on behavioural finance and social media influencers by presenting a structured framework for evaluating the effect of social media on investor decision-making. Originality/value It uniquely examines the interrelationships among key determinants and prioritizes the social media influencer type that influences investor decisions, using a hybrid Fuzzy DEMATEL and Fuzzy TOPSIS approach.