The popular sandwich chain Subway has raised a $3.4 billion bond, the largest of its kind, to pay off its acquisition debt. What Happened: The bond, secured by Subway’s U.S. franchisee royalties and intellectual property, was in high demand, with investor orders exceeding $20 billion, the Financial Times reported. This overwhelming interest allowed the debt package to be increased and the interest payments to be lowered. Subway will use the funds from this bond to pay off a portion of the $5.4 billion debt initially extended by a group of banks to finance the acquisition by the leveraged buyou…