September 2013 SSS Results
Amazon - In September, Amazon came in at 26.5%, which is a slight increase from August's 24%, and significantly above the rate of e-commerce growth (as reported by comScore).
Together with July and August data, this made for a Q3 2013 growth rate of 25.1%, which compares with 29% on Q2 2013. We are thus seeing a significant growth deceleration (-390 bps).
Modeling Amazon.com's Q3 2013 revenues
ChannelAdvisor's data is the most solid and transparent read we can get on Amazon.com before it reports its Q3 2013 earnings. There is a massive correlation (R2 = 0.8951) between Amazon.com's overall revenue growth rate and the growth rate reported by ChannelAdvisor for its 3P customers. This correlation actually exceeds the correlation between the ChannelAdvisor data and the Amazon.com North American segment (R2= 0.8073) or between ChannelAdvisor and the Amazon.com EGM North American segment (R2= 0.6711).
With such a solid relationship, by using ChannelAdvisor's Q3 2013 outcome (+25.1%) we can get a prediction of what kind of overall revenue growth Amazon.com is likely to report for Q3 2013. This is what we get (red dot is projection):
Hence, 25.1% ChannelAdvisor growth implies 18.3% revenue growth for the whole of Amazon.com in Q3 2013. The present consensus estimate, however, stands at 21.4% revenue growth. This means that Amazon.com is likely to miss the consensus revenue estimate.
Miss by how much?
Having a projected growth rate, we can answer this question as well. Amazon.com had revenues of $13 806 million in Q3 2012. A 18.3% growth rate thus projects revenues of $16 329 million for Q3 2013. With the present consensus being $16 770 million, this means Amazon.com is likely to miss revenue estimates by around $440 million.
Amazon.com has changed the nature of its relationship with book sellers, going from a commission to a wholesale model when accounting for ebook sales. This might have led to Amazon.com being able to report a lot more revenue (more than 3 times more revenue) for the same volume of ebook sales.
Since Amazon.com is not transparent about this change, it's impossible to know how much it inflates revenues, but it can be a substantial effect, adding up to $4.6 billion in revenue over a year. This means the impact on any single quarter can exceed $1 billion.
The most recent ChannelAdvisor data implies Amazon.com will miss revenue estimates for Q3 2013 by a full $440 million, likely coming in at a 18.3% growth rate where expectations are for a 21.4% growth rate. This is the result of a model with a very high R2 of 0.8951.
Disclosure: I am short AMZN. I wrote this article myself, and it expresses my own opinions. I am not receiving compensation for it (other than from Seeking Alpha). I have no business relationship with any company whose stock is mentioned in this article.