 Isabella Weber is an associate professor of economics at the University of Massachusetts Amherst, and she joins us now. Welcome to the program. Thanks so much for having me. Now, there's a lot of debate about the causes of recent inflation. In one paper, you argued that seller's inflation was a major culprit post-COVID. And in fact, you briefed the U.S. Federal Trade Commission on the topic earlier this year. I wonder if you could start by telling us what is seller's inflation? Yeah.