Jacob Sparks has developed a semiotic critique of markets that is based on the fact that “market exchanges express preferences.” He argues that some market transactions will reveal that the purchaser of a market good inappropriately prefers it to a similar non-market good. This avoids Brennan and Jaworski’s criticism that semiotic objections to markets fail as the meaning of market transactions are contingent social facts. I argue that Sparks’ argument is both incomplete and doomed to fail. It can only show that some preferences are morally problematic, not that the transactions that they lead to are immoral.