Mark Bietz

Mark Bietz is a marketing and ecommerce executive best known for helping build HalloweenCostumes.com and FUN.com into one of the largest online costume and pop-culture merchandise retailers in the world. As Chief Marketing Officer of the Mankato, Minnesota-based company, he led digital growth that scaled revenue roughly 10x-20x, championing data-driven email personalization and short-form video. A self-described curious operator who learned the business from brand to CRM to operations, he now also works as a fractional CMO and advisor to venture-backed and private-equity-backed brands, and speaks widely on modern ecommerce and the rise of agentic commerce.