Both large establishments and large cities are known to offer workers an earnings premium. In this paper, we show that these two premia are closely linked by documenting a new fact: when workers move to a large city, they also move to larger establishments. We then ask how much of the city-size earnings premium can be attributed to transitions to larger and better-paying establishments. Using administrative data from Spain, we find that 38 percent of the city-size earnings premium can be explained by establishment-size composition. Most of the gains from the transition to larger establishments realize in the short-term upon moving to the large city. Establishment size explains 29 percent of the short-term gains, but only 5 percent of the medium-term gains that accrue as workers gain experience in the large city. The small contribution to the medium-term gains is due to two facts: first, within large cities workers transition to large establishments only slightly faster than in smaller cities; second, the relationship between earnings and establishment size is weaker in large cities.

众所周知，大型企业和大城市都会为工人提供收入溢价。在本文中，我们通过记录一个新事实表明这两种溢价密切相关：当工人搬到大城市时，他们也会搬到更大的机构。然后，我们询问有多少城市规模的收益溢价可以归因于向规模更大、收入更高的机构的过渡。使用来自西班牙的行政数据，我们发现 38% 的城市规模收益溢价可以用机构规模构成来解释。向大型企业过渡的大部分收益在搬到大城市后会在短期内实现。机构规模解释了 29% 的短期收益，但只解释了 5% 的中期收益（随着工人在大城市获得经验而累积）。对中期收益的贡献很小是由于两个事实：第一，在大城市中，工人向大型企业的过渡仅比小城市快一点；其次，收入与机构规模之间的关系在大城市中较弱。