I've been a prime member for years and didn't know this.... Thank you very much, ill be sure to nickle and dime Amazon for all the value it offers.

You're entitled to know how much they make from Prime, but not the business specifics (you can't extract information from the profit, either, as not all prime costs the same - there is student membership, month-to-month, yearly, etc)

No, as a random shareholder you're not automatically entitled to all the details.

You are, however, entitled to the following three things:

1) Whatever information they provide has to be actually true to the best of their knowledge; so they can be vague or secretive, but "more than 100 million" has to literally mean that;

2) There's a set of core information that you are entitled to, but it doesn't go into as much detail;

3) Shareholders as a whole are entitled to whatever information they want; they can elect a board that will ensure that as much detail as you want gets publicized. But it's not likely that most shareholders in a public company will consider it a worthwhile decision.

Look at Apple as another example. They disclose the number of iPhones, iPads and Macs they sell, but they don't disclose:

- how much they make from Beats even though it was their largest acquisition.

- the number of watches or AppleTVs they sell. They are both assumed to be 1 billion dollar businesses.

- they say they have over 38 million subscribers to Apple Music but never give an exact number. Even though Apple Music is a $4 billion+ a year business.

Etc.