Cementing the case for collusion under the National Recovery Administration

•We collect new plant-level data for cement industry from 1929 through 1935.•Find that National Recovery Administration affected firms' responses to neighbors•Build spatial model to show how neighbors' costs affect own price under collusion•Narrative evidence shows mechanisms used to maintain collusion.

Macroeconomists have long debated the aggregate effects of anti-competitive provisions under the “Codes of Fair Conduct” promulgated by the National Industrial Recovery Act (NIRA). Despite the emphasis on these provisions, there is only limited evidence documenting any actual effects at the micro-level. We use a combination of narrative evidence and a novel plant-level dataset from 1929, 1931, 1933, and 1935 to study the effects of the NIRA in the cement industry. We develop a test for collusion specific to this particular industry. We find strong evidence that before the NIRA, the costs of a plant's nearest neighbor had a positive effect on a plant's own price, suggesting competition. After the NIRA, this effect is completely eliminated, with no correlation between a plant's own price and its neighbor's cost.