Shoppers on Amazon are unable to pre-order physical copies of some upcoming Disney films, as the entertainment company appears to have joined the growing list of suppliers in contract disputes with the US ecommerce group.

Neither company commented on why Disney films including Muppets Most Wanted and Captain America: The Winter Soldier are not available for pre-order on DVD or Blu-ray from Amazon's site.

So far this year, book publisher Hachette and Warner Brothers' studio, part of Time Warner, have both seen sales of some of their products halted or shipments dramatically slowed during contentious negotiations over supply contracts.

Amazon last month reported an operating loss of $15 million for the quarter to the end of June and forecasts that its operating loss for the current quarter could be between $410 million and $810 million.

Heavy investment

It attributes its lack of profitability to its heavy investment in growing businesses such as its cloud computing services, but investors have not been patient. Shares are off more than 20 per cent this year.

Analysts speculate that the company’s increasingly aggressive stance on supplier negotiations come as it feels pressure from investors to stanch its losses.

Viewers can pre-order many of the affected Disney films on Amazon Instant Video. Alternatively, they can sign up to be notified when they are able to pre-order physical copies of some of the films. The digital version of the Muppets film available for pre-order on Amazon will come out today in the US, while Captain America will be released on Instant Video on August 19th.

The company’s highest-profile dispute has been its fight with Hachette, part of the French Lagardère group. It has lasted nearly four months, far longer than the few weeks it had suspended sales of Time Warner films.

Pressure

Amazon on Saturday published a letter calling for Hachette authors to put pressure on their publisher to accept lower ebook prices.

The company said that only by taking "action to reduce sales of their titles in our store" had Hachette "grudgingly began to even acknowledge" Amazon's argument that high ebook prices were depressing readers' willingness to buy them. On Sunday, more than 900 authors shot back at Amazon by taking out a full-page ad in the New York Times calling on the company to stop intentionally slowing book sales during supplier disputes.

Amazon has called the writers “human shields” for their publisher. – Copyright The Financial Times Limited 2014