The effect of social media influencer's content format on the customer engagement on Instagram

In recent years, influencer marketing has grown its popularity as a communication strategy for brands to reach their target audience and achieve desired brand outcomes through social media. Despite the growing importance of influencer marketing, a comprehensive understanding of the factors that impact engagement remains inadequate, particularly at the social media platform level. To address this gap in the literature, this study investigates the impact of content format on social media engagement with both sponsored and non-sponsored social media influencer (SMI) posts on Instagram, as well as the effect of brand endorsement on engagement in a market where sponsorship disclosure is legally mandatory. The results show that sponsored content created by influencers has a lower engagement rate than non-sponsored content, regardless of the content format. The study also explores the impact of content format on engagement and reveals meaningful distinctions between each content format such that consumers engage more with carousel posts than reels and more with reels than photo posts. Using a secondary data approach, we analyze users' actual social media engagement behaviors with sponsored and non-sponsored content on Instagram, as well as individual content formats. Our research provides valuable insights for advertisers and brands to make informed decisions about selecting influencers and developing successful influencer marketing campaigns.