During the 2007 tax season, Professor Peter Tufano, founder of D2D Fund, collaborated with H&R Block to study offering U.S. Savings Bonds (Series I) at 27 H&R Block tax preparation offices. 3,729 clients with federal refunds greater than $500 received a scripted offer to purchase US Savings Bonds. 220 (or 5.9%) of these clients chose to purchase bonds spending an average of $228 each which resulted in tax time savings of $50,100.