Tong Yang Industry Company, Ltd. (Tong Yang) (defendant) manufactured aftermarket replacement parts for vehicles that it sold through autobody shops and retailers, including Keystone Automotive Industries (Keystone) (defendant). Tong Yang’s products included replacement grilles for Chevrolet and GMC vehicles. The grilles’ centers had placeholders in the shape of Chevrolet’s trademarked bowtie and GMC’s trademarked letter emblems. Customers would purchase the actual emblems directly from Chevrolet and GMC to insert into these placeholder spots. General Motors Corp. (General Motors) (plaintiff) owned the Chevrolet bowtie and GMC letter trademarks. General Motors sued Tong Yang and Keystone for trademark infringement, alleging that Tong Yang’s grilles caused a likelihood of post-sale confusion. General Motors alleged that the logo-shaped placeholders on Tong Yang’s grilles were still visible after consumers mounted the Chevrolet and GMC emblems onto the grilles, and the placeholders’ low-quality appearance caused harm to the General Motors brand. The district court found that there was no likelihood of post-sale confusion about the source of Tong Yang’s grilles’ and granted summary judgment to the defendants. General Motors appealed.