In September a federal judge approved the U.S. Justice Department's settlement with Hachette, HarperCollins and Simon & Schuster, which were accused of conspiring in a price-fixing scheme.
Among other things, the agreement requires the publishers to abandon the pricing system that they had conceived with Apple before it released its iPad tablet in 2010. The publishers must also provide the funds for the Kindle credit.
"We think these settlements are a big win for our customers and look forward to lowering prices on more Kindle books in the future," the Amazon Kindle Team said in the email sent to customers.
Amazon.com Inc. told its Kindle customers over the weekend that they will be contacted when the credit is applied to their account if the court approves the settlement in February. Customers don't need to do anything to receive the credit.
Amazon said that while it doesn't know the amount of the credit until the court approves the settlements, the state Attorneys General estimate it will be from 30 cents to $1.32 for every eligible Kindle book purchased between April 2010 and May 2012. The credit can be used to buy e-books or print books, or customers can request a check in the amount of the credit.
Shares of Amazon fell $3.36, or 1.3 percent, to $239 in morning trading Monday. They peaked at $264.11 in mid-September and traded as low as $166.97 last December.