The retail giant sent out an email yesterday to KDP authors and publishers with some good news. According to the screen shot I saw (and confirmed online), payments for ebooks sold in the Kindle Store will now be sent out on a monthly basis, 60 days after a given month ends. Amazon is no longer going to require a minimum payment threshold. Instead payments from each of the Kindle Stores will be processed automatically (with the exception of the Brazilian Kindle Store).
Amazon has always managed more timely payments than legacy publishers, some of which make royalty payments to authors twice a year (if you're lucky), and now Amazon is going a step better.
My only puzzlement today is why this took so long. Amazon announced a similar change to their publishing division's payment processing back in March 2013. That was when Amazon Publishing announced that they would be sending royalty checks monthly instead of quarterly, in much the same way that I get my Amazon affiliate payments on a monthly basis.
Amazon has confirmed the change in payment processing on the KDP website.