Our data show that nearly all firms borrow for the first time in their life from a single bank, but soon afterward some of them start borrowing from additional banks. Duration analysis shows that the likelihood of a firm substituting a single relationship with multiple relationships increases with the duration of that relationship. It also shows that this substitution is more likely to occur for firms with more growth opportunities and for firms with poor performance. The analysis of the ex post effects of the initiation of multiple relationships, in turn, shows that firms with higher levels of investment prior to the initiation of multiple relationships increase their investment even further when they start to borrow from multiple banks and that firms with poor prior performance continue to perform poorly afterward. These results suggest that concerns with hold-up costs, together with an unwillingness by the incumbent bank to increase its exposure to a firm because of its past poor performance, are the key reasons for these firms to initiate an additional relationship this early in their life.