Antitrust authorities consider commodity bundling as an extension of monopoly power to other markets which harms consumers. This paper analyzes quality competition and its effect on consumer surplus for the case of commodity bundling by a multi-product firm in a vertically differentiated industry. When the firm bundles a high quality good, we show that bundling negatively affects the quality of a competing good, consumer surplus, and welfare. When the firm bundles a low quality good instead, bundling raises the quality of a competing good, enhances consumer surplus, and may increase the welfare.
- Consumer surplus
- Optimal quality
- Vertical product differentiation