Amazon wins big with Prime Day

US online sales from Amazon's recent four-day Prime Day summer sales event came in at $24.1 billion, surpassing projections and marking a 30.3% increase from a year ago, according to Adobe. Sales were strong in office supplies, electronics and home improvement, and mobile shopping accounted for more than half of transactions. The event spurred a wave of promotions across the retail industry, with deep discounts and consumer anticipation of new tariffs contributing to the sales surge, and this year's online total equaled the impact of two traditional Black Friday events.