events have helped to refocus investors and issuers on the benefits that bond insurance provides. A number of well-publicized municipal defaults, bankruptcies and restructurings occurred, which proved that bond insurance remains valuable in the public finance market. For example, holders of insured bonds were kept whole by Assured Guaranty and National Public Finance Guarantee in situations involving Detroit, Michigan; Jefferson County, Alabama; Harrisburg, Pennsylvania; Stockton, California and Puerto Rico. In the secondary market, insured bonds have generally exhibited significant price stability relative to comparable uninsured bonds of distressed issuers. Additionally, investors were spared the burdens of negotiating or litigating to defend their rights. Although the financial crisis caused most bond insurers to cease issuing insurance policies, the insurance has continued to remain available from highly rated providers, including legacy insurers and new industry participants. History: 1970s–2008 Prior to the 2008 financial crisis, bond insurers suffered few material losses. Notable exceptions in the municipal sector include: a 1984 Ambac loss on its exposure to the Washington Public Power Supply System (WPPSS), which helped establish the value of bond insurance; and a 1998 MBIA loss on its exposure to Allegheny Health, Education and Research Foundation (AHERF), which declared bankruptcy. As publicbonds.org points out, a 1994 BusinessWeek article called MBIA "an almost perfect money machine". The BusinessWeek story noted that, as of that time, MBIA had seen only one loss. By the late 1990s and early 2000s, about 50% of U.S. municipal bonds were insured. Although penetration of insurance in the municipal bond market is far lower today than when numerous triple-A insurers were active, the ability of Assured Guaranty to continue insuring municipal bonds that were issued during a prolonged period of low interest rates and narrow credit spreads is evidence that a market continues to exist for municipal bond insurance. Timeline 1971 saw the introduction of municipal bond insurance in the U.S. by American Municipal Bond Assurance Corp. (subsequently renamed AMBAC and later "Ambac"). Ambac was the first separately capitalized insurance company formed for the purpose of insuring bonds. In 1973 Municipal Bond Insurance Association (subsequently renamed "MBIA") formed, followed by Financial Guaranty Insurance Company ("FGIC") in 1983. Financial Security Assurance Inc. ("FSA", now known as Assured Guaranty Municipal) formed in 1985. FSA was the first bond insurer organized to insure non-municipal bonds, and it established the business of insuring asset-backed securities (ABS). These became known as the "big four" bond