<PAGE>
SAFECO COMMON STOCK TRUST
SAFECO TAXABLE BOND TRUST
SAFECO MANAGED BOND TRUST
SAFECO TAX-EXEMPT BOND TRUST
SAFECO MONEY MARKET TRUST
SUPPLEMENT TO THE PROSPECTUS DATED APRIL 30, 1998
SUPPLEMENT DATED DECEMBER 31, 1998
THE FOLLOWING INFORMATION SUPPLEMENTS THE TRUSTS' CLASS A & B PROSPECTUS:
1. The following information replaces the second and third paragraphs on page
56:
Except as stated below, broker-dealers of record may be paid commissions on
(i) sales of Class A shares of $1 million or more based on an investor's (or
a related group of investors') cumulative purchases during each successive
one year period beginning on the date of the initial purchase at net asset
value and (ii) sales of Class A shares to qualified benefit plans. A 1% CDSC
will be imposed on redemptions made within the first 18 months, except with
respect to participant-directed redemptions from qualified plans.
Commissions on sales of Class A shares of $1 million or more (except for
sales to certain qualified benefit plans see below) may be paid up to a rate
of 1.00% of the amount up to $3 million, .50% of the next $47 million and
.25% thereafter. Commissions on sales of Class A shares to qualified benefit
plans may be paid as follows:
<TABLE>
<CAPTION>
NUMBER OF PLAN
PARTICIPANTS INVESTED
IN SAFECO FUNDS AMOUNT SOLD COMMISSION
- --------------------- ----------------- --------------------------
<S> <C> <C>
50-199 under $1 million .50%
50-199 $1 million or 1.00% up to $3 million
more .50% of the next $47
million
.25% thereafter
200 or more no minimum 1.00% up to $3 million
.50% of the next $47
million
.25% thereafter
</TABLE>
SAFECO Securities reserves the right to charge back commissions if plan
sales fail to meet the criteria above.
