Microsoft vs Amazon: Azure revenue grew 43%, but Amazon's cash flow swings negative

Microsoft and Amazon are both spending at extraordinary scale to own the AI cloud, and their valuations are surprisingly close — Microsoft near 25.3 times forward earnings and Amazon around 27.7 times. The harder question is which company is turning infrastructure dollars into better economics, especially as both deepen model partnerships and run into physical constraints that money alone cannot instantly solve.

Microsoft has the cleaner cash-flow story: Azure revenue grew 43% and Microsoft Cloud revenue rose 27% to $59.3 billion. Commercial remaining performance obligations reached $678 billion, up 84%. Yet Microsoft trades around 55 times free cash flow because AI infrastructure spending absorbs cash faster than earnings alone suggest, and cloud gross margins are pressured by depreciation and AI usage. Amazon's AWS is growing almost as fast from an enormous base — second-quarter sales rose 37% to $42.2 billion, with operating income jumping to $16.6 billion from $10.2 billion, a roughly 39% segment operating margin. But Amazon's trailing operating cash flow of $161.4 billion was offset by a $7.6 billion free-cash-flow outflow as property and equipment purchases rose by $66.1 billion, primarily for AI.

Hedge funds favored Amazon in Q2, with 369 holders up from 353 in Q1, while Microsoft fell to 273 holders from 282. The outcome hinges on whether AWS, advertising, and retail logistics eventually absorb Amazon's buildout costs and produce a much larger earnings base — or whether Microsoft's ability to spread investment across Azure, Microsoft 365, GitHub, security, and Copilot keeps it the more efficient converter of capital into durable profit.