Assured Guaranty Ltd
A financial guaranty insurer that promises to pay bondholders if a borrower defaults, Assured Guaranty is one of the world's largest in its field, backing municipal, infrastructure, and structured-finance bonds, and lately moving into annuity reinsurance. It was formed in 2003 in Bermuda as a holding company for ACE Limited's guaranty operations, then grew by acquiring Financial Security Assurance in 2009. Its fitting name signals its business: a reliable "guaranty" that bondholders can feel "assured" about.