This study investigates how social media influencers (SMIs) affect corporate reputation by connecting micro-level communication choices (narrative vs. non-narrative style and the presence or absence of sponsorship disclosure) to macro-level reputation outcomes, that earlier research has largely ignored because most studies have focused only on purchase intention or brand attitude.

Using two experimental studies with realistic video stimuli and analysed through MANCOVA, the results show that when an influencer uses a personal narrative and does not disclose any sponsorship, followers rate the company’s reputation significantly higher. However, once a sponsorship disclosure (paid promotion) appears, the advantage of the narrative disappears, and corporate reputation is not enhanced. Mediation tests further confirm that narrative content lowers persuasion knowledge compared with non-narrative content, but disclosure activates persuasion knowledge and removes the protective effect of storytelling.

This study bridges micro-level influencer communication with macro-level corporate reputation by extending signaling theory, institutional theory, and social learning theory. For practice, the findings offer clear guidance: companies can improve their overall reputation through influencer narratives only when sponsorship disclosure is absent or minimal. When disclosure is required, using a narrative style alone is not enough to prevent reputational damage.