Group identity in the form of family, ethnicity, or gender is a powerful predictor of social preferences, as shown by theory and empirical work. In particular, people generally favor in-group over out-group members. Such favoritism can have positive or negative repercussions. On the one hand, it can lead to inefficient transactions and lost opportunities. On the other hand, group identity may also entail trust, reciprocity, and efficiency due to shared norms and understandings. In recent research with Patrick Behr and Andreas Madestam, we gauge these opposing hypotheses, examining one important form of group identity, gender, and the consequences of own-gender preferences for outcomes in the credit market. We use microcredit transactions as they are an ideal ground to test these different hypotheses, relying heavily on transaction between loan officers and borrowers.