UPS (UPS) shares have fallen out of favor this year, and that may not change, Barclays analyst Brandon Oglenski warns. The sell-side analyst slashed his rating on UPS to Underweight — or the equivalent of Sell — on Monday, citing a host of fundamental challenges. Chief among them is a weak freight environment and the potential loss of volumes from e-commerce giant Amazon (AMZN). The company could also lose market share to a more efficient rival in FedEx (FDX).

Barclays’s downgrade is the latest black eye on the year for UPS. Shares are down 14% year to date, lagging FedEx’s 8% gain, as the company struggles with a surge in lower-margin e-commerce volumes. Investor sentiment has also been damaged by a surprise earnings miss in July and a deep cut to full-year sales guidance. UPS reports third quarter earnings on October 24, and the Street is bracing for another dose of bad news — potentially another warning.