The above corrections have been made to the historical data. In addition, some earlier observations in the historical data have been corrected. However, these observations were published correctly on the original statistical releases.

As of the release dated February 25, 2002, the H.15 no longer reports a 30-year constant maturity yield for Treasury securities and begins reporting a yield for Treasury securities with 25 years or more remaining to maturity.

The changes reflect the Treasury's announcement on January 30, 2002, that, effective February 18, it would cease supplying an estimate of the 30-year constant maturity yield and that it would commence supplying a long-term yield based on a basket of long-dated securities.

As indicated in footnote 12 of the release, the new long-term rate is based on an unweighted average of the bid yields for all Treasury fixed-coupon securities with remaining terms to maturity of at least 25 years. A factor to adjust the daily long-term average to estimate a 30-year rate is available at the Treasury web site reported in footnote 13 of the release.

The H.15 site has links to the original September 17, 2001, release as well as to the revised releases for that date and for September 24.

Data for most of the interest rates reported in the H.15 release of September 17, 2001, were missing for September 11-13 because of inactive markets or delays in data processing arising from the disasters of September 11.

On September 25 the Treasury released the data that had been missing for September 13 regarding the constant maturity interest rates on Treasury securities and the secondary rates on bills. On October 1, 2001, the Federal Reserve issued a revised version of the H.15 release of September 17 to show the September 13 values of those series and the correspondingly updated values of the averages for the week ending September 14; also on October 1, 2001, the Federal Reserve issued a revised version of the September 24 release to show the new values of the averages for the week ending September 14.

On July 31, 2001, the Department of the Treasury began the weekly issuance of 4-week bills. On August 27, 2001, the Treasury stopped reporting secondary market yields for 1-year Treasury bills, the final issuance of which was on February 27, 2001.

Effective with the issue of September 4, 2001, the H.15 statistical release reflects these changes by reporting the secondary market rate for 4-week bills and by no longer reporting the secondary market rate for 1-year bills.

In addition, the H.15 now reports a 1-month constant maturity rate, which the Treasury began calculating when it introduced the 4-week bill.

Rates for fixed-rate payers in interest rate swaps, as collected under the auspices of the International Swaps and Derivatives Association, Inc., are being added. These swap rates are for maturities of 1, 2, 3, 4, 5, 7, 10, and 30 years.

No longer appearing on the release are auction highs for 3-month, 6-month, and 1-year Treasury bills. These figures continue to be available from the Treasury's website: http://www.publicdebt.treas.gov/of/ofrespr.htm. Also being dropped is the Treasury composite (an unweighted average of yields on all outstanding bonds neither due nor callable in less than 10 years).