Amazon halts preorders of Warner Bros. Blu-rays & DVDs in latest contract dispute

As of Wednesday, Blu-ray and DVD copies of a number of Warner Bros. films cannot be preordered at Amazon's site, where users are invited to sign up for an email alert when the item becomes available. Digital copies of titles like "The Lego Movie," which is currently one of the top digital home releases in the U.S., remain available for purchase through the Amazon Instant Video service.

The lack of preorders have apparently been prompted by ongoing negotiations with Warner Bros., according to The New York Times, who revealed that Amazon has been declining preorders for Time Warner movies since mid-May.

The spotlight on Amazon's approach with Time Warner comes in the midst of the online retailer's high-profile negotiations with bookseller Hachette. Like in the Warner Bros. dispute, Amazon has been blocking preorders of popular titles from Hachette, but has also gone one step further and even delayed delivery of new purchases from the publisher. Similar tactics have been used by Amazon to gain leverage with Germany's Bonnier Media Group.

The Amazon-Hachette dispute has been under particular scrutiny as Amazon dominates the e-book market while competitors such as Apple are looking to gain ground. But Apple suffered a serious setback last year when it was successfully sued by the U.S. government for conspiring with book publishers to raise e-book prices. Apple has formally appealed the ruling.

Apple led the charge in convincing publishers to switch to a so-called "agency" pricing model. That prevented content owners from being able to sell the same titles at a lower price elsewhere, without offering the same price on Apple's iBooks platform — a "most favored nations" clause.

In contrast, the e-book industry prior to the launch of the first iPad was under the "wholesale model" preferred by Amazon. In that model, resellers such as Amazon had the power to set prices, selling titles at or below cost if they chose to do so.

Like in the e-book market, Amazon and Apple also compete in sales of other digital content, including movies. Hit recent Warner Bros. titles including "The Lego Movie" and "300: Rise of an Empire" are also sold through Apple's iTunes Store without any issue, though Apple does not sell physical copies of media like Amazon.