Fashion categories make a comeback compared to June with early back-to-school sales. "As many economic ... spearheaded by Amazon Prime Day. Walmart WMT, Target TGT, and many specialty stores ...

But those increases have shown signs of cooling more recently. Amazon's online sales rose 4% year-on-year in the April to June period, after no growth at the start of the year, the company said.

Amazon said its e-commerce sales were poised to look especially weak because Prime Day, when discounts typically drive a surge of buying, was moved from June to July. "Big tech's been a mixed bag ...