Dive Brief:

• Amazon's top shows attracted more than 5 million people worldwide to its Prime subscription as of early 2017, according to newly released company documents reported on by Reuters. The U.S. audience for all Amazon Prime video programming was about 26 million. 
• Prime Originals accounted for roughly one-quarter of the estimated total Prime signups from late 2014 to early 2017, per the documents, which compared metrics for 19 Amazon-exclusive shows, including cost, viewership and how many people they helped attract to Prime. 
• The documents showed that Amazon evaluates TV shows on a "cost per first stream" basis — the cost to convert a customer to Prime. The company divides the show's production and marketing expenses by the number of users that stream the program after signing up. The lower the figure is, the better it is for Amazon. "The Grand Tour," the first season of "The Man in the High Castle" and "Bosch" had the lowest cost per first stream. 

Dive Insight:

Even as over-the-top streaming services like Netflix and Amazon Prime Video have started to usurp TV in terms of the audiences and talent they attract, these companies have remained incredibly cagey about sharing internal figures. The documents obtained by Reuters not only show how original video is paying off for Amazon but also how it thinks about its programming strategically as a sort of loss leader customer acquisition tool for Prime, which primarily acts as an e-commerce shopping platform for the company. Video is one of Amazon's largest expenses, according to sources cited by Reuters, but the company hasn't, to date, released how many Prime subscribers it obtains. The data show that broader interest programming can help Amazon draw subscribers inexpensively, according to its own calculations. 

As it has examined its cost per customer, Amazon has started producing more commercially appealing shows and programming that has a broader appeal outside the U.S. to compliment critically acclaimed shows like "Transparent," which earned high marks from critics and earned several Gold Globe wins and nominations, but didn't draw as large an audience as other shows, according to Reuters. Amazon recently announced plans to make a prequel to "The Lord of the Rings" to replicate the success of a cultural phenomenon like HBO's "Game of Thrones."

Investing in premium content and original programming is helping video streaming services stand out among the competition, as platforms compete for the growing number of cord cutters. Amazon Prime competitor Netflix announced earlier this year that it would spend between $7.5 billion and $8 billion on original content in 2018, and continue to invest in original programming in the next few years.