downturn in the domestic economy or changes in our mix of business may result ----------------------------------------------------------------------------- in more homeowners defaulting and our losses increasing. -------------------------------------------------------
Losses result from events that reduce a borrower's ability to continue to make mortgage payments, such as unemployment, and whether the home of a borrower who defaults on his mortgage can be sold for an amount that will cover unpaid principal and interest and the expenses of the sale. Favorable economic conditions generally reduce the likelihood that borrowers will lack sufficient income to pay their mortgages and also favorably affect the value of homes, thereby reducing and in some cases even eliminating a loss from a mortgage default. A deterioration in economic conditions generally increases the likelihood that borrowers will not have sufficient income to pay their mortgages and can also adversely affect housing values. Housing values may decline even absent a deterioration in economic conditions due to declines in demand for homes, which in turn may result from changes in buyers' perceptions of the potential for future appreciation, restrictions on mortgage credit due to more stringent underwriting standards or other factors.
The mix of business we write also affects the likelihood of losses occurring. In recent years, the percentage of our volume written on a flow basis that includes segments we view as having a higher probability of claim has continued to increase. These segments include loans with LTV ratios over 95% (including loans with 100% LTV ratios), FICO credit scores below 620, limited underwriting, including limited borrower documentation, or total debt- to-income ratios of 38% or higher, as well as loans having combinations of higher risk factors.
Approximately 6.5% of our primary risk in force written through the flow channel, and 72% of our primary risk in force written through the bulk channel, consists of adjustable rate mortgages in which the initial interest rate may be adjusted during the five years after the mortgage closing ("ARMs"). (We classify as fixed rate loans adjustable rate mortgages in which the initial interest rate is fixed during the five years after the mortgage closing.) We believe that during a prolonged period of rising interest rates, claims on ARMs would be substantially higher than for fixed rate loans, although the performance of ARMs has not been tested in such an environment. Moreover, even if interest rates remain unchanged, claims on ARMs with a "teaser rate" (an initial interest rate that does not fully reflect the index which determines subsequent rates) may also be substantially higher because of the increase in the mortgage payment that will occur when the fully indexed rate becomes effective. In addition, we believe the volume of "interest-only" loans (which may also be ARMs) and loans with negative amortization features, such as pay option ARMs, increased in 2005 and 2006. Because interest-only loans and pay option ARMs are a relatively recent development, we have no data on their historical performance. We believe claim rates on certain of these loans will be substantially higher than on loans without scheduled payment increases that are made to borrowers of comparable credit quality.
The amount of insurance we write could be adversely affected if lenders
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and investors select alternatives to private mortgage insurance. ---------------------------------------------------------------
These alternatives to private mortgage insurance include: -- lenders originating mortgages using piggyback structures to avoid private mortgage insurance, such as a first mortgage with an 80% loan-to-value ("LTV") ratio and a second mortgage with a 10%, 15% or 20% LTV ratio (referred to as 80-10-10, 80-15-5 or 80-20 loans, respectively) rather than a first mortgage with a 90%, 95% or 100% LTV ratio that has private mortgage insurance, -- lenders and other investors holding mortgages in portfolio and self-insuring, -- investors using credit enhancements other than private mortgage insurance, using other credit enhancements in conjunction with reduced levels of private mortgage insurance coverage, or accepting credit risk without credit enhancement, and -- lenders using government mortgage insurance programs, including those of the Federal Housing Administration and the Veterans Administration.