In spite of the large and growing importance of the employer size-wage premium, previous attempts to account for this premium using observable worker or employer characteristics have had limited success. The problem is that, while most theoretical explanations for the size-wage premium are based on the matching of employers and employees, previous empirical work has relied on either worker surveys with little information about the employer, or establishment surveys with little information about the workers. In contrast, this study uses the newly created Worker-Establishment Characteristic Database, which contains linked employer-employee data for a large sample of U.S. manufacturing workers and establishments, to examine seven explanations for the employer size-wage premium. A number of the explanations can account for some of the observed cross-sectional variation in worker wages. However, none of the explanations can fully account for the employer size-wage premium. In the end there remains a large, significant, and unexplained premium paid to workers of large employers.

Examining the Employer-Size Wage Premium in the Manufacturing, Retail Trade, and Service Industries Using Employer-Employee Matched Data by Kimberly Bayard and Kenneth R. Troske. Published in volume 89, issue 2, pages 99-103 of American Economic Review, May 1999

We use a unique new data set that combines data on individual workers and their employers to estimate marginal productivity differentials among different types of workers. We then compare these to estimated relative wages, leading to new evidence on productivity‐based and nonproductivity‐based explanations of the determination of wages. Among our findings are (1) the higher pay of prime‐aged workers (aged 35–54) and older workers (aged 55+) is reflected in higher point estimates of their relative marginal products, and (2) for the most part, the lower relative earnings of women are not reflected in lower relative marginal products.