StockX is a resale platform launched in 2016 that revolutionized the secondary market by introducing stock market-style bid/ask pricing and mandatory authentication for all transactions. Before StockX, resale pricing was opaque—negotiated individually on eBay, forums, or in person. StockX created price transparency: anyone could see what items actually sold for, track price trends, and make informed decisions. The platform's authentication process addressed the fake goods problem plaguing online resale—every item ships to StockX for verification before reaching buyers. StockX expanded beyond sneakers into streetwear, electronics, and collectibles, processing billions in transactions. The platform's influence extends beyond commerce: it shaped how people think about streetwear as an investment, provided data for market analysis, and legitimized resale as an industry. Critics note that StockX's fees, occasional authentication failures, and stock market framing contributed to treating clothing as pure commodities, but its impact on streetwear's secondary market infrastructure is undeniable.