As the importance of horizontal brand extension for company growth strategy is increasing, brand managers are trying to extend their brands to a new category. However, the difficulty of horizontal brand expansion is far higher than vertical extension, which extends the brand in the same category, because the lack of similarity between existing and new business categories can cause negative consumer responses. To provide meaningful implications for both managers and researchers, this study analyzed the horizontal brand expansion cases of Timonet Co. Ltd. which has expanded from FinTech into ‘car sharing’, ‘electronic signature’, and ‘cultural technology exhibition’ businesses. By analyzing the case of Timonet Co. Ltd. this study extracted factors that can be considered to be important in the horizontal brand expansion and considered them based on existing theories.