Amazon continues to gain share in U.S. e-commerce market, JPM says

JPMorgan's analysis indicates Amazon significantly expanded its U.S. e-commerce market share in Q2, reaching 46.8% after accelerating global first-party and third-party sales growth to 10% year-over-year, outpacing the broader 5.3% U.S. online sales increase. The firm projects Amazon's share to near 50% by Q4 and reiterates the stock as a "Best Idea," despite anticipating a slight deceleration in overall U.S. e-commerce growth in late 2025, while maintaining a long-term bullish outlook on e-commerce penetration.

Analysis

According to a JPMorgan research update, Amazon (AMZN) significantly expanded its U.S. e-commerce leadership in the second quarter by capturing an estimated 46.8% market share, an increase of over two percentage points year-over-year. The company's performance notably outpaced the broader market, with both its global first-party and third-party sales growth accelerating to 10% YoY in constant currency, compared to a modest 5.3% YoY growth for the overall U.S. online sales sector. This acceleration is attributed to strong performance in essentials, record-fast delivery speeds, and the continued expansion of the Prime ecosystem. JPMorgan projects this market share dominance will continue, forecasting Amazon's share to reach 47.4% in Q3 and 49.2% by Q4. While the bank anticipates a slight deceleration in overall U.S. e-commerce growth in the second half of 2025 due to tougher comparisons and potential tariff impacts, it maintains a bullish long-term outlook, projecting e-commerce penetration could rise from approximately 23% in 2024 to over 40%, reinforcing its classification of Amazon stock as a 'Best Idea'.

Key Decisions for Investors

• Given Amazon's accelerating sales growth and significant market share gains, which starkly outpace the broader e-commerce sector, investors could view the stock as a core holding to capitalize on its strengthening market dominance.
• Evaluate the durability of Amazon's competitive moat, specifically its logistics network and Prime ecosystem, as these are the primary drivers behind its projected share expansion towards 50% by year-end.
• While the near-term outlook is strong, it is prudent to monitor for potential sector-wide headwinds in late 2025, such as tougher comps and tariff effects, which could moderate growth even as Amazon continues to outperform.