Amazon store sales growth was negative: here's why

A statistic in Amazon's fourth quarter results raised some eyebrows.

Sales at physical stores were down 3% from the same quarter of the previous year. This seems important, since it is the first comparison of one year to the other of Amazon for Whole Foods since its acquisition of the grocery store chain. 2017.

Amazon executives, however, poured cold water on all speculation about a decline in Whole Foods sales at the badyst results conference.

CFO Brian Olsavsky said the drop was mainly due to a change in accounting. In the fourth quarter of last year, Amazon has aligned Whole Foods' financial calendar on its own schedule, generating an additional five days of revenue in the fourth quarter of 2017.

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Amazon has also launched its Whole Foods food collection and delivery service – which it offers through Prime Now – in cities across the country through 2018. These sales are reported in Amazon's online revenue instead physical sales.

Taking these two factors into account, Whole Foods sales increased 6% over the previous year, Olsavsky said in his investor appeal.

This leaves the rest of Amazon's physical store initiatives, including Amazon Books, with no reliable way to discern growth or lack of sales growth. It will take a while before obtaining reliable data on Go's or Amazon's 4-star store fleet, both of which have expanded rapidly in 2018 and are expected to further develop in 2019.

It also means that online sales at Whole Foods have probably boosted online sales, contributing to a better outlook than the one that was announced. Analysts at Nomura Instinet wrote in a note to investors Friday that Whole Foods sales contributed about 1% to online store sales growth of 12.5%.