|FEDERAL NATIONAL MORTGAGE ASSOCIATION FANNIE MAE filed this Form 10-Q on 05/06/2011|
mortgage rates of our existing outstanding loans, loan age and other factors. On a continuous basis, management makes judgments about the appropriateness of the risk assessments and will make adjustments as necessary to properly assess our interest rate exposure and manage our interest rate risk. The methodologies used to calculate risk estimates are periodically changed on a prospective basis to reflect improvements in the underlying estimation process.
Interest Rate Sensitivity to Changes in Interest Rate Level and Slope of Yield Curve
As part of our disclosure commitments with FHFA, we disclose on a monthly basis the estimated adverse impact on the fair value of our net portfolio that would result from the following hypothetical situations:
In measuring the estimated impact of changes in the level of interest rates, we assume a parallel shift in all maturities of the U.S. LIBOR interest rate swap curve.
In measuring the estimated impact of changes in the slope of the yield curve, we assume a constant 7-year rate and a shift of 16.7 basis points for the 1-year rate and 8.3 basis points for the 30-year rate. We believe the aforementioned interest rate shocks for our monthly disclosures represent moderate movements in interest rates over a one-month period.
Duration gap measures the price sensitivity of our assets and liabilities to changes in interest rates by quantifying the difference between the estimated durations of our assets and liabilities. Our duration gap analysis reflects the extent to which the estimated maturity and repricing cash flows for our assets are matched, on average, over time and across interest rate scenarios to the estimated cash flows of our liabilities. A positive duration gap indicates that the duration of our assets exceeds the duration of our liabilities. We disclose duration gap on a monthly basis under the caption Interest Rate Risk Disclosures in our Monthly Summaries, which are available on our website and announced in a press release.
The sensitivity measures presented in Table 46, which we disclose on a quarterly basis as part of our disclosure commitments with FHFA, are an extension of our monthly sensitivity measures. There are three primary differences between our monthly sensitivity disclosure and the quarterly sensitivity disclosure presented below: (1) the quarterly disclosure is expanded to include the sensitivity results for larger rate level shocks of plus or minus 100 basis points; (2) the monthly disclosure reflects the estimated pre-tax impact on the market value of our net portfolio calculated based on a daily average, while the quarterly disclosure reflects the estimated pre-tax impact calculated based on the estimated financial position of our net portfolio and the market environment as of the last business day of the quarter; and (3) the monthly disclosure shows the most adverse pre-tax impact on the market value of our net portfolio from the hypothetical interest rate shocks, while the quarterly disclosure includes the estimated pre-tax impact of both up and down interest rate shocks.
In addition, Table 46 also provides the average, minimum, maximum and standard deviation for duration gap and for the most adverse market value impact on the net portfolio for non-parallel and parallel interest rate shocks for the three months ended March 31, 2011.