Merchandise is a noncount noun. Therefore it is singular.
- S. Open merchandise is a hit.
- Pier 1 Imports’ merchandise is sourced from hundreds of vendors throughout the world.
Merchandising—the activity of trying to sell goods or services by advertising them or displaying them attractively—is also noncount and thus singular.
- Merchandising is the heart of retailing.
- Merchandising is any practice which contributes to the sale of products to a retail consumer.
Photo credit: Seagram’s Guia Vintage Madrid