Bookshop.org pays our booksellers 30% of the cover price of all books sold through them. That means that we lose money on any book with less than a 30% wholesale discount. If your discount is under 20%, we will increase the sale price of the book to make up for this loss. If you do not want your book's price increased, please offer a wholesale discount greater than 20%.
If you are an IngramSpark author, you must offer a 40% wholesale discount; Ingram's 20% distribution fee is non-negotiable, so to give Bookshop.org a 20% wholesale discount, you need a 40% discount overall. You can read about how to set wholesale discounts here: https://www.ingramspark.
If you are a KDP author, if you select Expanded Distribution your wholesale discount is automatically 40%, which will allow it to be sold at list price on Bookshop.org.