[tdmule]

The closest I can see to someone asserting they do is

https://www.mhpbooks.com/is-amazon-one-of-the-companies-work...

But the thrust of that article is more suspicion that Amazon is not mentioned in the leaks and questioning the reliability of the company's word. It does cite one source, described in the article as non-mainstream, which asserts that Amazon was a part of PRISM, but that source fails to cite any leak.

http://www.marketoracle.co.uk/Article40822.html

Edit: I should mention that the first article casting doubt on Amazon's reliability is published by an independent publishing company, historically an industry that has been at odds with Amazon and harmed by its business practices.