AMERICAN CENTURY GOVERNMENT INCOME TRUST
PROSPECTUS SUPPLEMENT
CAPITAL PRESERVATION * GOVERNMENT AGENCY MONEY MARKET
SHORT-TERM TREASURY * INTERMEDIATE-TERM TREASURY * LONG-TERM TREASURY
INFLATION-ADJUSTED TREASURY * SHORT-TERM GOVERNMENT * GNMA
Supplement dated September 1, 1999 * Prospectus dated August 1, 1999
The following replaces the highest and lowest quarterly return chart on page 3
of the Investor Class Prospectus.
The highest and lowest quarterly returns for the period reflected in the bar
chart are:
Highest Lowest
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Capital Preservation 2.12% (2Q 1989) 0.63% (2Q 1993)
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Government Agency Money Market 2.06% (1Q 1990) 0.65% (2Q 1993)
The following replaces the section "What is the difference between the three
funds?" on page 7 of the Advisor Class Prospectus.
WHAT IS THE DIFFERENCE BETWEEN THE THREE FUNDS?
The funds differ in the maturity of the debt securities they purchase. This
difference is shown in the chart below.
Expected Weighted Average Maturity Range
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Short-Term Treasury 13 months-3 years
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Intermediate-Term Treasury 3-10 years
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Long-Term Treasury 10-30 years
The following replaces the third paragraph on page 12 of the Investor Class
Prospectus and page 8 of the Advisor Class Prospectus.
The fund also may buy traditional U.S. Treasury securities that are not
inflation-indexed.
The fund also may buy inflation-indexed securities issued by the U.S. government
agencies and government-sponsored organizations. The fund may invest up to 35%
of its total assets in these securities.
The following replaces the third paragraph on page 14 of the Investor Class
Prospectus and page 10 of the Advisor Class Prospectus. The fifth paragraph on
these pages should be deleted.
The fund also may buy U.S. government securities. The U.S. government, its
agencies and instrumentalities issue these securities. These securities include
mortgage-backed securities. The U.S. government's financial support of these
agencies and instrumentalities varies.
The following replaces the fifth paragraph on page 19 of the Investor Class
Prospectus and page 15 of the Advisor Class Prospectus.
Casey Colton
Mr. Colton, Vice President and Portfolio Manager, has been a member of the GNMA
team since January 1994. Mr. Colton joined American Century in 1990. He holds a
bachelor's degree in business administration from San Jose State University and
a master's degree from the University of Southern California. He is a Chartered
Financial Analyst and a Certified Public Accountant.
SH-SPL-17793 9908
