IS research has shown the importance of trust in domains such as e-commerce or technology acceptance. Researchers also emphasize the importance of the identification of factors that influence trust. Unfortunately, the currently dominant reflective measurement does not offer these insights, and thus this contribution aims at developing a formative measurement model for trust. To achieve this, we address three research questions: a) How can trust be measured, considering trust and measurement theory? b) What indicators should be included in a formative measurement model for trust? c) What is the value of a formative measurement of trust compared to a reflective one? Our results show that the formative measurement model offers detailed insights on the impact of single factors influencing trust. We show that in our study, ability affects trust over twice as much other factors such as benevolence or trustor's propensity.