For months, I’ve had a book sitting on my desk: Swiftynomincs: How Women Mastermind and Redefine Our Economy. Published in January, the book by economist Misty L. Heggeness examines how Swift herself—and her legions of fans—power the economy in ways both seen and unseen.

In the book, Heggeness rattles off some numbers. The Eras Tour raked in $4 billion in revenue, and Swift controlled a reported 85% of it. Cities from Cincinnati to Los Angeles reported anywhere from $48 million to $320 million in revenue-boosting activity during the tour’s stops.

Her analysis also goes beyond the history-making Eras Tour. Swift’s business influence extends to monopoly-busting and intellectual property, through her battle with Ticketmaster and her Taylor’s Version re-records. The Eras Tour was one part of a year, 2023, in which women’s economic power was seen in full force, through the box office-shattering Barbie movie and more. The consumer spending was a sign that women were spending on themselves and their own interests—not just on their spouses and families. When she’s not writing about Swift, Heggeness usually studies what she calls gender economics, including themes like how marriage and divorce influence how families distribute resources within their households.