<PAGE>
GREEN CENTURY FUNDS
Supplement dated June 1, 2000 to Prospectus dated December 1, 1999
This Supplement updates certain information contained in the Green Century
Funds Prospectus dated December 1, 1999. You should retain both the
Supplement and the Prospectus for future reference. You may obtain
additional copies of the Prospectus, including a copy of the Prospectus
incorporating the changes below by calling 1-800-93-Green.
. The charts and tables below replace the similar information provided on
pages 3 and 4 of the Prospectus dated December 1, 1999.
. The section on page 18 regarding Year 2000 is deleted in its entirety.
How have the Funds performed in the past?
The charts and table below provide some indication of the risks of
investing in the Funds by illustrating that returns can differ from one
year to the next and by comparing this information to broad measures of
market performance. Each Fund's past performance is no guarantee of how it
will perform in the future.
Annual Total Returns
[GRAPH]
Green Century Balanced Fund
93 94 95 96 97 98 99
-- -- -- -- -- -- --
-0.47 -4.28 18.26 25.02 19.00 -10.10 76.39
[GRAPH]
Green Century Equity Fund
92* 93* 94* 95* 96 97 98 99
-- -- -- -- -- -- -- --
11.27 5.75 -1.10 35.09 21.26 35.71 32.32 21.97
As of March 31, 2000, the year-to-date return for the Green Century Balanced
Fund was 37.37%. As of the same date, the year-to-date return for the Green
Century Equity Fund was 2.59%.
<TABLE>
<S> <C>
Green Century Balanced
Fund
Best Quarter Ended
12/31/99 52.63%
Worst Quarter Ended
9/30/98 -21.97%
</TABLE>
<TABLE>
<S> <C>
Green Century Equity
Fund
Best Quarter Ended
12/31/98 24.46%
Worst Quarter Ended
9/30/98 -9.92%
</TABLE>
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Average Annual Total Returns
<TABLE>
<CAPTION>
For the periods ended 1 Year 5 Years Since Inception
December 31, 1999
<S> <C> <C> <C>
Green Century Balanced Fund 76.39% 22.78% 14.09%
(Inception March 18, 1992)
Lipper Balanced Fund Index 8.98% 16.33% 12.63%
Green Century Equity Fund 21.97% 29.11% 19.17%
(Inception June 3, 1991*)
S&P 500 Index 21.04% 28.56% 19.41%
</TABLE>
* The Green Century Equity Fund, which commenced investment operations in
September 1995, invests all of its assets in an existing separate registered
investment company which has the same investment objective as the Fund (the
Index Portfolio). Consistent with regulatory guidance, the performance for
the period prior to the Fund's inception, as listed below, reflects the
performance of the Index Portfolio adjusted to reflect the deduction of the
charges and expenses of the Fund.
What fees and expenses will I pay?
The following table describes the fees and expenses you may pay if you buy
and hold shares of the Green Century Funds.
<TABLE>
<CAPTION>
Balanced Fund Equity Fund/3/
<S> <C> <C>
Shareholder Fees (fees paid directly from your
investment)
Maximum Sales Charge (Load) Imposed on
Purchases -- --
Maximum Deferred Sales Charge (Load) -- --
Maximum Sales Charge (Load) Imposed on
Reinvested Dividends and Other Distributions -- --
Redemption Fee/1/ -- --
Exchange Fee -- --
Annual Fund Operating Expenses (expenses that
are deducted from Fund assets)
Management Fees 0.75% 0.20%
Distribution (12b-1) Fees 0.25% --
Other Expenses:
Administrative Fees/2/ 1.50% 1.30%
Total Annual Fund Operating Expenses 2.50% 1.50%
</TABLE>
(1) A fee of $10.00 is charged for redemptions by wire. There is no charge for
redemptions paid by check.
(2) Green Century Capital Management, Inc. (Green Century Capital Management),
the administrator of each Fund, pays the operating expenses of the Funds
(excluding interest, taxes, brokerage costs and other capital expenses and
any extraordinary expenses). For this and other services, each Fund pays
Green Century Capital Management an Administrative Fee at a rate such that
the Equity Fund's total annual expenses are limited to 1.50% of the Equity
Fund's average net assets and the Balanced Fund's total annual expenses
are limited to 2.50% of the Balanced Fund's average net assets up to $30
million, 2.25% on its average net assets from $30 million to $100 million,
and 1.75% on the Balanced Fund's average net assets in excess of $100
million.
(3) For the Equity Fund, the table reflects the fees and expenses of the
Equity Fund and of the Index Portfolio in which it invests its assets,
combined.
Example. This example is intended to help you compare the costs of investing
in a Green Century Fund with the cost of investing in other mutual funds. This
example assumes that: (1) you invest $10,000 in a Fund; (2) redeem all of your
shares at the end of the periods shown; (3) earn a 5% return each year; and
(4) the operating expenses remain the same. Although your actual costs may be
higher or lower, based on these assumptions your costs would be:
<TABLE>
<CAPTION>
1 Year 3 Years 5 Years 10 Years
<S> <C> <C> <C> <C>
Balanced Fund $253 $779 $1331 $2836
Equity Fund $153 $474 $ 818 $1791
</TABLE>
