Studies have shown that smaller businesses are less likely to have extensive security in place because of the false sense of safety being small. What is more worrying is that small businesses are being attacked more frequently in today’s environment. Since protective measures often require significant managerial vigilance, an appropriate level of awareness and concern among managers may be a prerequisite for adequate security protection. Given its importance, there is a need to understand the factors that influence managers’ security concerns. Using the Model for Managerial Perceptions of Security Risk as a framework, we explore the factors that influence security concerns of small businesses. Ten technology start-ups in Singapore participated in this study. Findings provide an in-depth understanding of the factors – Organizational Environment, IS Environment and Individual Characteristics. Two new factors that significantly influence managers’ concern are identified – Trust between Managers and Employee, and Alignment to Business Needs. With a better understanding of these factors, more effective security management can be designed to heighten security consciousness of managers in start-ups. Findings also provide an impetus for researchers to conduct future studies in this domain.