Incomplete Wage Posting
研究企业为何选择不发布固定工资而采用谈判工资，发现当工人生产率差异大且谈判权力接近霍西奥斯条件时，企业偏好谈判，但谈判均衡无法最大化总净收入且可能非帕累托最优。
We consider a directed search model in which workers differ in productivity. Productivity becomes observable to firms after assessing their workers on the job, but it is not verifiable. Firms with vacancies choose between posting a noncontingent wage and leaving wages subject to bargaining with the worker. Under wage bargaining, firms cannot optimize the trade-off between paying higher wages and having a larger probability of filling vacancies. But wage bargaining makes wages increasing in worker productivity and so may allow firms to attract better workers into the vacancy. When workers' heterogeneity is large and bargaining powers come close to satisfying Hosios's rule, firms opt for bargaining. Yet, equilibria with bargaining fail to maximize aggregate net income and sometimes are not constrained Pareto optimal.