Daimler-Chrysler ($36 Billion, 1998)

Billed as a merger of equals between German engineering and American muscle, Daimler-Chrysler collapsed under a culture clash so severe that Daimler sold Chrysler for $7.4 billion—a 79% loss from the $36 billion deal value, destroying two-thirds of the original investment. This destruction of value is 50% worse than the HP-Autonomy collapse, making it the worst-performing mega-merger in the automotive industry by percentage loss.