Multiple reputable sources report that Amazon Prime Day sales fell by approximately 41% on the first day compared to the previous year.
Amazon Prime Day sales fall 41% in its first day.

FactVerify
Source: factverify.com
What the Evidence Shows
The claim states that Amazon Prime Day sales fell 41% on its first day. This is supported by several independent and credible sources including Bloomberg, Forbes, and Yahoo Finance. According to these reports, Momentum Commerce, a company managing Amazon sales for numerous brands, observed a 41% decline in sales on the first day of the event compared to last year.
The context provided indicates that this drop occurred during the first day of an expanded four-day Prime Day event, which may have influenced consumer purchasing patterns by spreading sales over more days. While the overall event might still project growth over multiple days, the specific claim about a 41% drop on the first day is accurate and consistently reported across multiple outlets. There is no contradictory information in the search results disputing this figure.