The American Recovery and Reinvestment Act dedicated $787 billion to stimulate the U.S. economy and mandated the release of the data describing the exact distribution of that money. The dataset is a large and complex one; one of its distinguishing features is its bi-hierarchical structure, arising from the distribution of money through agencies to specific projects and the natural aggregation of awards based on location. To offer a comprehensive overview of the data, a visualization must incorporate both these hierarchies. We present TreeCovery, a tool that accomplishes this through the use of two coordinated treemaps. The tool includes a number of innovative features, including coordinated zooming and filtering and a proportional highlighting technique across the two trees. TreeCovery was designed to facilitate data exploration, and initial user studies suggest that it will be helpful in insight generation. RATB (Recovery Accountability and Transparency Board) has tested TreeCovery and is considering including the concept in their visual analytics. (C) 2011 Elsevier Inc. All rights reserved.