<PAGE>
SAFECO COMMON STOCK TRUST
SUPPLEMENT TO THE NO-LOAD CLASS PROSPECTUS DATED APRIL 30, 1997
SUPPLEMENT DATED AUGUST 11, 1997
THE FOLLOWING INFORMATION REPLACES THE PARAGRAPH FOLLOWING THE SECTION CAPTIONED
"PORTFOLIO MANAGERS--BALANCED FUND" ON PAGE 43:
The equity portion of the Balanced Fund is co-managed by Rex L. Bentley,
Vice President, SAM, and Lynette D. Sagvold, Assistant Vice President,
SAM, and the fixed-income portion is managed by Michael Hughes,
Assistant Vice President, SAM. Mr. Bentley was Vice President and
Investment Counsel at the investment advisory firm of Badgley, Phelps
and Bell Investment Counsel, Inc. from 1990 to 1995. He was a securities
analyst for SAFECO Corporation from 1975 to 1983. Ms. Sagvold was a
portfolio manager and analyst for First Interstate Bank from 1993 to
1995, and a portfolio manager and analyst for Key Trust Company from
1985 to 1993. Mr. Hughes was Vice President and a portfolio manager for
First Interstate Capital Management Company from 1995 to 1996, and Vice
President and portfolio manager for First Interstate Bank of California
from 1988 to 1995.