Based on a survey of the Kindle Store, indie authors are selling more ebooks with each passing quarter while the Big Five are selling less:
The Big Five are still earning a disproportionate share of the ebook revenues, but it is not as large as it used to be.
According to the report, the 1,200 publishers that make up the monthly AAP Statshot report only account for 32% of all Kindle ebook unit sales, down from 45%. The AAP 1,200's share of gross ebook revenue in the Kindle Store is also down from its historical high of 64%, and now only accounts for 50% of unit sales.
The Big Five account for about 80% of the monthly revenue reports (and that's based on the AAP's own list of participating publishers).
The above stats don't reflect the print market, which still accounts for the lion's share of book sales (but will it stay that way forever?) so it is obviously less than a complete view of the book market.
But this is enough to tell us that the AAP's recent reports of a declining market do not reflect the ebook market but publishers shrinking share of that market. The same is true for Nielsen Pubtrack, which (in spite of what they claim) tracks an even smaller share of the ebook market.
And since we know that the official view of the ebook market is incredibly incomplete, how much do you want to bet that the print market will show a similar discrepancy?