What makes a market transaction morally repugnant?

Many people find it morally impermissible to put kidneys, jury duty exemptions, or permits for having children on the free market. All of these are examples of repugnant transactions-market transactions that third parties want to prevent. In two studies (N = 1,554), using respondents' judgments of 51 different market transactions across 21 characteristics, we show that repugnance can be decomposed into five higher-order dimensions: moral outrage, need for regulation, incommensurability, exploitation, and unknown risk. Repugnance toward the 51 market transactions was highly consistent across two samples. Our results can help identify mismatches between public sentiments and current regulations (selling carbon emissions is currently legal but considered repugnant), anticipate responses to novel markets that have not been publicly scrutinized (often arising from technological advances, such as markets for "designer babies"), and help design less repugnant markets (e.g., by making the risks involved in a transaction known to sellers).