Why Amazon was down today after market

Amazon's stock declined by over 7% in after-hours trading on July 31, 2025, despite a strong quarterly performance. The downturn is primarily attributed to the company's operating income guidance for the current quarter, which left investors disappointed. 1. **Disappointing Guidance**: Amazon's guidance for the third quarter indicated a potential headwind from tariffs, with an expected operating income between $15.5 billion and $20 billion. This widened guidance on the lower end may have raised concerns among investors about the impact of tariffs on the company's profitability. 2. **Significant AI Investment**: Amazon's commitment to spending over $100 billion on AI this year, primarily for building data centers and software, may have led to investor apprehension. This substantial investment could be seen as a negative sign in the short term, given the significant upfront costs associated with AI development. In summary, Amazon's stock decline today can be attributed to disappointing guidance and significant AI investment. These factors, combined with the broader market conditions and investor sentiment, contributed to the stock's performance.