<PAGE>
MITCHELL HUTCHINS SERIES TRUST
SUPPLEMENT TO THE PROSPECTUS DATED MAY 1, 1998
January 19, 1999
Dear Investor,
This is a supplement to the Prospectus of Mitchell Hutchins Series Trust
("Trust") that describes several changes of which investors should be aware.
GLOBAL GROWTH PORTFOLIO
At a meeting held October 29, 1998, the shareholders of the Portfolio approved
the following changes to the manner in which the Portfolio's assets are managed:
. An Investment Advisory and Administration Contract between Mitchell
Hutchins Asset Management Inc. ("Mitchell Hutchins") and the Fund
under which Mitchell Hutchins has the enhanced role of allocating the
Portfolio's investments between U.S. and foreign investments. Mitchell
Hutchins is now responsible for the day-to-day management of the U.S.
investments segment of the Portfolio.
. A Sub-Advisory Contract between Mitchell Hutchins and Invista Capital
Management, Inc. ("Invista"), under which Invista manages the foreign
investments segment of the Portfolio.
. A policy to permit the board of trustees to appoint sub-advisers and
to approve amendments to sub-advisory agreements without shareholder
approval.
These new investment management arrangements became effective on November 2,
1998. As a result of these changes, the Trust's Prospectus is hereby amended as
follows:
1. The paragraph describing Global Growth Portfolio on page MH 20 is replaced
by the following:
Global Growth Portfolio has an investment objective of long-term capital
appreciation. This Portfolio invests primarily in the common stocks of
companies based in the United States, Europe, Japan and the Pacific Basin.
Under normal circumstances, at least 65% of the Portfolio's total assets is
invested in common stocks and securities convertible into common stocks.
The Portfolio may also hold other types of securities, including non-
convertible investment grade bonds, government bonds and money market
securities of U.S. and foreign issuers and cash (foreign currencies or U.S.
dollars). The Portfolio may invest up to 10% of its net assets in illiquid
securities.
<PAGE>
Mitchell Hutchins allocates Global Growth Portfolio's assets between U.S.
investments and foreign investments and manages the assets allocated to
U.S. investments. Mitchell Hutchins has appointed Invista Capital
Management, Inc. ("Invista") as the Portfolio's Sub-Adviser to manage the
assets allocated to the Portfolio's foreign investments. In determining the
portion of the Portfolio's assets allocated between U.S. and foreign
investments, Mitchell Hutchins considers the expected performance of the
U.S. equity markets versus that of certain developed foreign countries
included in the Morgan Stanley Capital International Europe, Australia and
Far East Index (EAFE Index). The EAFE Index is a well known index that
reflects most major equity markets outside the United States. Mitchell
Hutchins uses this analysis in determining the relative attractiveness of
the U.S. and foreign market segments. If Mitchell Hutchins believes that a
segment shows greater potential for higher returns on a risk-weighted
basis, Mitchell Hutchins may allocate a higher portion of Portfolio assets
to that segment.
Mitchell Hutchins currently expects to reevaluate the allocation of Global
Growth Portfolio's assets monthly. It does not expect to reallocate assets
to reflect relatively minor changes (that is, less than 5%) in the asset
allocation model. The Portfolio may effect a reallocation of assets by
using cash flows from the purchase or redemption of its shares in addition
to selling portfolio securities from one segment and reinvesting the
proceeds in the other segment. The Portfolio may also use futures contracts
to adjust its exposure to U.S. and foreign equity markets in connection
with a reallocation. Mitchell Hutchins will determine the extent to which
the Portfolio uses futures contracts for this purpose and is responsible
for implementing its decisions using futures contracts.
For the U.S. portion of Global Growth Portfolio's investments, Mitchell
Hutchins expects to follow a disciplined investment process that relies on
the Mitchell Hutchins Equity Research Team and the Mitchell Hutchins Factor
Valuation Model. The Model screens a universe of over 3,500 companies to
identify undervalued companies with relatively strong earnings momentum
that rank well in three measures:
. Value: projected dividends, cash flow, earnings and book values
. Momentum: earnings and prices to identify companies that could
surprise on the upside
. Economic sensitivity: forecast of performance of different equity
securities and industries under various economic scenarios
The Equity Research Team then applies traditional fundamental analysis and
may speak to the management of these companies, as well as their
competitors. Based on the Team's evaluations, Mitchell Hutchins selects
securities for purchase and sale for the Portfolio.
<PAGE>
For the foreign portion of Global Growth Portfolio's investments, Invista
makes a qualitative analysis of a company's fundamental business prospects
and then analyzes the long-term ability of the company to generate free
cash flow. Invista considers factors such as competitive position, market
share, competitive strengths, industry supply and demand trends, economic
conditions, balance sheet strength, earnings, book value, return on equity,
revenue growth and margin development in analyzing the quality of the
company. Invista also makes a quantitative assessment of country risk,
which it considers in assessing the companies under analysis, and analyzes
a large universe of companies to determine the most appropriate foreign
investments for the Portfolio. Invista may make changes in investments as
opportunities or prospects change for particular countries, industries or
companies.
Under normal circumstances, Global Growth Portfolio will invest at least
80% of its total assets in securities of issuers in the United States and
countries represented in the EAFE Index. The Portfolio may invest up to 20%
of its assets in securities of issuers located in other countries, for
example, in Canada and in emerging markets. Mitchell Hutchins may also
invest, as part of the U.S. portion of the Portfolio, up to 10% of the
Portfolio's total assets in U.S. dollar-denominated equity securities and
bonds of foreign issuers that are traded on recognized U.S. exchanges or in
the U.S. over-the-counter market.
Mitchell Hutchins and Invista may restructure a substantial portion of the
Portfolio's investments after assuming day-to-day portfolio management to
reflect their investment philosophies and processes. This restructuring
could result in higher than usual portfolio turnover for the current and
next fiscal years.
2. The following replaces the initial paragraph under "Management" on page MH
32:
The board, as part of its overall management responsibility, oversees
various organizations responsible for each Portfolio's day-to-day
management. Mitchell Hutchins, the investment adviser and administrator for
each Portfolio, makes and implements all investment decisions and
supervises all aspects of the operations of all the Portfolios except
Strategic Fixed Income Portfolio, Aggressive Growth Portfolio and the
foreign investments segment of Global Growth Portfolio. Mitchell Hutchins
supervises the activities of the Sub-Advisers and supervises all other
aspects of these Portfolios' operations.
The Fund has applied for exemptive relief to the SEC to permit its board to
appoint or replace sub-advisers and to amend sub-advisory contracts without
obtaining shareholder approval each time. The requested exemptive order is
expected to require that the shareholders of a Portfolio approve this sub-
adviser approval policy prior to its implementation. To date, this policy
has been approved only by the shareholders of Global Growth Portfolio.
<PAGE>
3. The following replaces the last paragraph on page MH 33 and the second full
paragraph on page MH 35:
Mitchell Hutchins (not the Fund) pays Invista a fee for its services as
Sub-Adviser for the foreign investments segment of Global Growth Portfolio
at an annual rate of 0.29% of the Portfolio's average daily net assets.
Invista is located at 1800 Hub Tower, 699 Walnut, Des Moines, Iowa 50309.
Invista, which was founded in 1984, is an indirect wholly owned subsidiary
of Principal Life Insurance Company and manages substantially all of
Principal Life Insurance Company's equity accounts, in addition to
providing investment advice to other affiliated and non-affiliated
customers. As of August 31, 1998, Invista managed approximately $26 billion
in client assets.
Mitchell Hutchins is responsible both for allocating Global Growth
Portfolio's assets between U.S. and foreign markets and for managing the
U.S. investments segment. T. Kirkham Barneby is responsible for the asset
allocation decisions for the Portfolio. Mr. Barneby is a managing director
and chief investment officer - quantitative investments of Mitchell
Hutchins. He is also a vice president of the Trust. Mr. Barneby rejoined
Mitchell Hutchins in 1994, after being with Vantage Global Management for
one year. During the eight years that Mr. Barneby was previously with
Mitchell Hutchins, he was a senior vice president responsible for
quantitative management and asset allocation models. Mr. Barneby assumed
his Global Growth Portfolio responsibilities on November 2, 1998.
Mark A. Tincher is primarily responsible for the day-to-day management of
Global Growth Portfolio's U.S. investments. Mr. Tincher is a managing
director and chief investment officer -- equities of Mitchell Hutchins,
responsible for overseeing the management of equity investments. He is also
a vice president of the Trust. Prior to joining Mitchell Hutchins in March
1995, Mr. Tincher worked for Chase Manhattan Private Bank, where he was
vice president and directed the U.S. funds management and equity research
area. At Chase since 1988, Mr. Tincher oversaw the management of all Chase
equity funds (the Vista Funds and Trust Investment Funds). Mr. Tincher
assumed his Global Growth Portfolio responsibilities on November 2, 1998.
Invista is the Sub-Adviser for Global Growth Portfolio and manages the
Portfolio's foreign investments. Scott D. Opsal is primarily responsible
for the day-to-day management of the Portfolio's foreign investments. Mr.
Opsal has served as executive vice president and chief investment officer
of Invista since 1997. Previously, he served as a vice president of Invista
from 1986 to 1997. Mr. Opsal assumed his Global Growth Portfolio
responsibilities on November 2, 1998.