For it to be predatory pricing in the US, Amazon would have to be selling the e-books at below sellers cost. If they are making any profit regardless of how small, it isn’t predatory pricing.
Amazon was selling e-Book that cost them from between $15 and $18 for $9.99. That is, very obviously, below wholesale cost. They were taking a huge loss on everyone of them they sold. No one, ever, did a forensic accounting audit on Amazon's e-book sales. Amazon claims they were making a profit on overall e-book sales, but that was merely their claim. . . without evidence. . . in years in which Amazon overall posted huge losses.
You apparently really don't know what predatory pricing is. It is using artificially low pricing to keep competition OUT of a market with the intention of making competition impossible. It is the EFFECT it has, not the pricing per se. Amazon claimed they were using this pricing as "a loss leader" to attract buyers to buy other e-books in the non-best-seller and non-A-list categories. This is a specious argument because there is absolutely no way they could possibly make up the losses of their "loss leaders" by selling close-to-cost junk sale books that are not attractive to customers who are attracted to best sellers and A-list titles. They are NOT at all the same customer base.
Best seller fans don't buy books titled "The Economic Collapse of the Hittite Empire and its Impact on the Punic Wars." Their tastes just don't overlap at all. They are just not the same kind of readers. To make up the loss from just one "loss leader," and show any kind of profit, Amazon would have to sell SIX to NINE non-"loss leader" e-books to someone who was attracted to Amazon by the "loss-leader" pricing to show a profit. Can you show me anyone who buys a bestseller and then buys junk history, tech manuals, non-A-list books, etc???? I know of no one who does that. No, they'll be back to buy another "loss-leader" or A-List book that is popular at a bargain price.
These buyers aren't going to buy much else but name brand books by known authors, the bread-and-butter books that pay the bills and keep bookstores in business and allow them to compete.
I am educated as an Economist. . . and have been a CEO. These are just the facts of economics and the way reality works as I see it.