Labor markets unravel when workers and firms match inefficiently early under limited information. I argue that a significant determinant of unraveling is the presence of a secondary market, where firms can poach workers, and its transparency: how well firms can ascertain workers' value once they are employed by competitors. While early hiring reduces the probability of hiring a high-type worker, it prevents rivals from learning about the worker, making poaching difficult. When secondary markets are very transparent, unraveling disappears. However, the matching remains inefficient due to the incentives of low-tier firms to communicate that they have not hired top-quality workers. (JEL C78, D47, J23, J44, M51)
Akhil Vohra (Tue,) studied this question.