SEATTLE, Aug. 25 -- Amazon now spends more money on property and equipment than its entire business generates in cash. The company publishes that fact itself, in a small reconciliation table near the back of its quarterly filing, and it is the most important number in American technology this month.

Over the twelve months to June 30, Amazon's operations produced $161.4 billion of cash, up a third on the year before. Over the same twelve months it spent $169.0 billion on property and equipment, net of what it sold. The difference is free cash flow, and Amazon reports it as minus $7.6 billion.

A year earlier the same measure was positive $18.2 billion.

Amazon rose 1.27 per cent to $261.91 on Monday afternoon and remains the least damaged...