This story requires our BI Prime membership. To read the full article, simply click here to claim your deal and get access to all exclusive Business Insider PRIME content. More first-party suppliers will move to the third-party marketplace. Amazon's wholesale suppliers, commonly called first-party vendors, account for roughly 40% of Amazon's sales volume. Their products are bought by Amazon, who then resells them at a higher margin. But in recent years, there's been reports of Amazon reducing its first-party business, pushing more brands to go third-party instead.