[NATIONAL ASSET MANAGEMENT CORE EQUITY FUND LOGO]



                                   PROSPECTUS
                               DATED JUNE 1, 1999
                                  SUPPLEMENTED
                                  MARCH 6, 2000




National  Asset  Management  Core Equity Fund is a core equity fund designed for
individual and institutional investors. The Fund seeks to provide investors with
high total investment return.

THE SECURITIES AND EXCHANGE  COMMISSION HAS NOT APPROVED OR DISAPPROVED OF THESE
SECURITIES OR PASSED ON THE ADEQUACY OF THIS PROSPECTUS.  ANY  REPRESENTATION TO
THE CONTRARY IS A CRIMINAL OFFENSE.

PROSPECTUS
                                TABLE OF CONTENTS

An Overview of the Fund.....................................................   2
Fees and Expenses...........................................................   3
Investment Objectives, Principal Investment Strategies and Related Risks....   4
Investment Advisor..........................................................   5
Shareholder Information.....................................................   7
Distributions and Taxes.....................................................  10

- --------------------------------------------------------------------------------

AN OVERVIEW OF THE FUND

The goal of the Fund is to earn high total investment  return.  This consists of
capital appreciation and current income.

The Fund primarily  invests in common stocks of large and middle  capitalization
U.S.  companies  ("core"companies).  The Advisor  stresses a blend of growth and
value securities by utilizing its multiple attribute philosophy and process. Our
multiple  attribute  philosophy and process is investing in different  styles of
stocks.  The Advisor  strives to posture the portfolio to be in sync with equity
trends in various economic environments.

PRINCIPAL RISKS OF INVESTING IN NATIONAL ASSET MANAGEMENT CORE EQUITY FUND

There is the risk that you could lose money on your  investment  in the National
Asset  Management  Core Equity Fund.  This could happen if any of the  following
events happen:

*    The stock market goes down

*    Interest rates go up which can result in a decline in the equity market

*    Large and  medium  capitalization  stocks  fall out of favor with the stock
     market

*    Stocks in the Fund's  portfolio do not increase  their earnings at the rate
     anticipated

WHO MAY WANT TO INVEST IN NATIONAL ASSET MANAGEMENT CORE EQUITY FUND

The Fund may be appropriate for investors who:

*    Are pursuing a long-term goal such as retirement

*    Want to diversify their investment  portfolio by investing in a mutual fund
     that emphasizes investments in core companies

*    Want to reduce the volatility of a pure growth or value style of investing

*    Are willing to accept higher  short-term  risk along with higher  potential
     for long-term total return

The Fund may not be appropriate for investors who:

*    Are pursuing a short-term goal or investing emergency reserves

*    Wish to have the equity portion of their portfolio invested in stocks other
     than core U.S. companies

PROSPECTUS                             2

                                FEES AND EXPENSES

This table  describes the fees and expenses that you may pay if you buy and hold
shares of the Fund.

SHAREHOLDER FEES
   (fees paid directly from your investment)
Maximum sales charge (load) imposed on purchases
   (as a percentage of offering price)..............................       None
Maximum deferred sales charge (load)
   (as a percentage of the lower of original purchase
   price or redemption proceeds)....................................       None

ANNUAL FUND OPERATING EXPENSES*
(expenses that are deducted from Fund assets)
Management Fees.....................................................       0.50%
Distribution and Service (12b-1) Fees...............................        None
Other Expenses......................................................       2.00%
                                                                         ------
Total Annual Fund Operating Expenses................................       2.50%
Fee Reduction and/or Expense Reimbursement..........................     (1.55)%
                                                                         ------

Net Expenses........................................................       0.95%
                                                                         ======

- ----------
*    Other  Expenses are  estimated  for the first fiscal year of the Fund.  The
     Advisor has contractually  agreed to reduce its fees and/or pay expenses of
     the Fund to ensure  that Total  Annual  Fund  Operating  Expenses  will not
     exceed 0.95%. This contract's term is indefinite and may be terminated only
     by the Board of Trustees.  If the Advisor does waive any of its fees or pay
     Fund expenses, the Fund may reimburse the Advisor in future years.

EXAMPLE

This  example is intended to help you compare the costs of investing in the Fund
with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods
indicated and then redeem all of your shares at the end of those periods. The
Example also assumes that your investment has a 5% return each year and that the
Fund's  operating  expenses  remain the same.  Although your actual costs may be
higher or lower, under the assumptions, your costs would be:

   One Year........................................................  $  97

   Three Years.....................................................  $ 302

                                       3                              PROSPECTUS

INVESTMENT OBJECTIVES, PRINCIPAL INVESTMENT STRATEGIES AND RELATED RISKS

The Fund's  investment goal is to provide  investors with high total  investment
return by using a  combination  of  different  equity  styles to  diversify  the
portfolio.  The Advisor calls this  approach to investing in different  types of
stocks multiple attribute diversification. High total investment return consists
of capital appreciation and current income.

Under normal market conditions,  the Fund will invest at least 65% of its assets
in the equity securities  generally  considered to be core holdings. A company's
market capitalization is the total market value of its outstanding common stock.
The Fund  considers  core holdings to be large and medium size  companies with a
market capitalization of over $1 billion.

The  Advisor  examines  both growth and value  attributes  in the  selection  of
securities  so  that  the  portfolio  may  benefit  from  the  current  economic
environment.  To  determine  which style of  investing  to focus on, the Advisor
utilizes the following indicators:

*    Fundamental indicators,  which focus on economic momentum, S&P 500 earnings
     and interest rates

*    Valuation  indicators,  which  include  comparisons  of value versus growth
     stocks, focusing on price-to-sales ratios and price-to-earnings trends

*    Technical  indicators  which  include an analysis of the relative  strength
     between value versus growth and high versus low quality trends

The Fund will normally invest in the following three types of equity securities:

*    Growth  Securities.  Common  stocks that meet the  Advisor's  criteria  for
     five-year  annual  earnings-per-share  growth rates.  These securities must
     also exhibit no decline in the normalized  annual  earnings-per-share  rate
     during the last five years

*    Securities  with low  price-to-earnings  ratios.  The Advisor defines these
     securities as those common stocks with  price-to-earnings  ratios below the
     average of the companies included in the S&P 500 Index

*    Securities that pay high  dividends.  Common stocks that pay dividends at a
     rate above the average of the companies included in the S&P 500 Index

The Advisor utilizes a systematic, disciplined investment process when selecting
individual securities. This includes:

*    Screening a database for liquidity and the criteria listed above

*    Scoring  each  issue  emphasizing  fundamental,   valuation  and  technical
     indicators

PROSPECTUS                             4

*    Security  analysis that further  evaluates the company and the stock.  This
     includes   an   analysis  of  company   fundamentals   such  as   earnings,
     profitability and management; valuation such as price/earnings,  price/book
     and yield;  and  technical  analysis  emphasizing  individual  stock  price
     trends.

Under normal  market  conditions,  the Fund will stay fully  invested in stocks.
However,   the  Fund  may  temporarily  depart  from  its  principal  investment
strategies by making  short-term  investments in cash equivalents in response to
adverse market,  economic or political  conditions.  This may result in the Fund
not achieving its investment objective.

In  keeping  with its  investment  approach,  the  Advisor  does not  anticipate
frequent buying and selling of securities.  This means that the Fund should have
a low  rate of  portfolio  turnover  and  the  potential  to be a tax  efficient
investment.   This  should  result  in  the  realization  and   distribution  to
shareholders  of lower capital  gains,  which would be considered tax efficient.
The anticipated lack of frequent trading also leads to lower transaction  costs,
which could help to improve performance.

During the Fund's  initial  period of operations  and during times when the Fund
experiences  periods of heavy cash in-flows from  shareholders  purchasing  Fund
shares,  the Fund may not be fully  invested in  securities as described in this
prospectus, but rather, partially invested in cash and cash equivalents.

SPECIFIC RISKS OF INVESTING IN THE NATIONAL ASSET MANAGEMENT CORE EQUITY FUND

The  principal  risks of  investing  in the Fund that may  adversely  affect the
Fund's net asset value or total return are discussed  above in "Principal  risks
of investing in National  Asset  Management  Core Equity  Fund." Risks which are
characteristic  of equity  investing  are MARKET RISK,  the risk that the market
value of a security may move up and down,  sometimes rapidly and  unpredictably.
These  fluctuations  may  cause a  security  to be worth  less  than  the  price
originally  paid for it, or less than it was worth at an  earlier  time.  Market
risk may affect a single issuer,  industry,  sector of the economy or the market
as a whole;  MANAGEMENT  RISK,  the risk that a strategy used by the Advisor may
not produce the intended  result;  and VALUATION RISK, the risk that the markets
may not place the expected value on a particular stock holding.

INVESTMENT ADVISOR

National Asset Management Corporation is the investment advisor to the Fund. The
investment advisor's address is 400 West Market Street, Suite 2500,  Louisville,
KY 40202.  As of December  31, 1999,  the  investment  advisor  manages over $13
billion  in assets for  institutional  investors  and other  mutual  funds.  The
investment  advisor  provides  advice on buying and selling  securities  for the
Fund.

                                       5                              PROSPECTUS

The  investment  advisor also  furnishes  the Fund with office space and certain
administrative  services and provides most of the personnel  needed by the Fund.
For its services,  the Fund pays the investment advisor a monthly management fee
based upon the average daily net assets of the Fund at the annual rate of 0.50%.

The  Advisors's   Investment   Management  Group,  a  committee  of  experienced
investment  professionals,  each of whom  has the  Chartered  Financial  Analyst
designation, will be responsible for the day-to-day management of the Fund.

ADVISOR INVESTMENT RETURNS

Set forth in the table  below  are  certain  performance  data  provided  by the
Advisor  relating to its  individually  managed  equity  accounts.  All of these
accounts have  substantially the same investment  objective as the Fund and were
managed using  substantially  similar  investment  strategies  and techniques as
those  contemplated  for use by the Fund.  The Investment  Management  Group for
these accounts will also manage the Fund. The results presented are not intended
to predict or suggest the return to be  experienced by the Fund or the return an
investor might achieve by investing in the Fund.

Results may differ because of, among other things, differences in brokerage
commissions paid, account expenses,  including  investment  advisory fees (which
expenses and fees may be higher for the Fund than for the accounts), the size of
positions  taken in relation to account  size,  diversification  of  securities,
timing of purchases and sales,  timing of cash  additions and  withdrawals,  the
private  character of the composite  accounts compared with the public character
of the Fund, and the tax-exempt  status of some of the account holders  compared
with  shareholders  in the  Fund.  Investors  should  be  aware  that the use of
different methods of determining  performance might have adversely  affected the
performance figures shown below.

Investors should not rely on the following  performance data as an indication of
future  performance  of the  Advisor  or the  Fund.  The  different  methods  of
determining  performance  as  described in the prior  paragraph  could result in
lower returns for the Fund than for the Advisor's  individually  managed  equity
accounts.

    ADVISOR'S EQUITY COMPOSITE                  AVERAGE ANNUAL TOTAL RETURN
     FOR PERIOD ENDED 12/31/99                  COMPOSITE           S&P 500
     -------------------------                  ---------           -------

           One Year                               21.4%              21.0%

           Three Years                            30.2%              27.5%

           Five Years                             30.5%              28.5%

           Ten Years                              19.7%              18.2%

PROSPECTUS                             6

1.  Results  account for both income and capital  appreciation  or  depreciation
(total  return).  Returns  are  dollar  weighted  and  net  of  commissions  and
management fees. The composite represents all discretionary accounts that do not
have material  restrictions.  Discretionary  accounts with material restrictions
were  omitted  from the  composite  because  such  accounts  would not have been
managed using  substantially  similar  investment  strategies  and techniques as
those  contemplated by the Fund. The composite complies with the Association for
Investment  Management and Research (AIMR) standards with a Level I and Level II
verification.  The verification was performed by Crowe,  Chizek and Company LLP,
independent public accountants.

2.  Investors  should note that the Fund will  compute and  disclose its average
annual  total return using the  standard  formula  required by SEC rules,  which
differs from  returns  calculated  under the method  noted above.  The SEC total
return calculation method requires that the Fund compute and disclose an average
annual  compounded  rate of return for one, five and ten year periods or shorter
periods  from  inception.  The  calculation  provides  a rate of  return  from a
hypothetical  initial  investment of $1,000 to an ending value as if shares were
redeemed at the end of the period. The formula requires that returns to be shown
for the Fund will be net of Fund advisory fees and all other portfolio operating
expenses.

The S&P 500 Composite Stock Price Index is an unmanaged  capitalization-weighted
index of 500 stocks designed to represent the broad domestic economy. Indexes do
not incur expenses and are not available for investment.

SHAREHOLDER INFORMATION

HOW TO BUY SHARES

There are several  ways to purchase  shares of the Fund.  An  Application  Form,
which  accompanies  this  Prospectus,  is used if you send money directly to the
Fund by mail or by wire. If you have questions about how to invest, or about how
to complete the  Application  Form,  please call  National  Asset  Management at
1-877-626-3863.  You may also buy  shares  of the Fund  through  your  financial
representative. After your account is open, you may add to it at any time.

You may open a Fund  account with  $500,000.  You may add to your account at any
time with $5,000. The minimum investment requirements may be waived from time to
time by the Fund.

BY MAIL.  You may send money to the Fund by mail.  All purchases by check should
be in U.S.  dollars.  Third party checks and cash will not be  accepted.  If you
wish to invest by mail,  simply complete the Application Form and mail it with a
check (made payable to the National  Asset  Management  Core Equity Fund) to the
Fund at the following address:

                                       7                              PROSPECTUS

National Asset Management Core Equity Fund
P.O. Box 641265
Cincinnati, OH 45264-1265

BY WIRE. If you are making an initial investment in the Fund by wire, before you
wire funds, you should call the Transfer Agent, America Data Services,  at (800)
385-7003 to advise them that you are making an investment by wire.  The Transfer
Agent will provide an account  number for you and will ask for your name and the
dollar amount you are  investing.  You will then receive your account number and
an order  confirmation  number.  You  should  then  complete  the  Fund  account
application  included  with the  prospectus.  Include  the  date  and the  order
confirmation  number on the Account  Application and mail the completed  Account
Application  to the  address at the top of the  Account  Application.  Your bank
should transmit immediately available funds by wire in your name to:

Firstar Bank , N.A.
ABA #0420-001-3
DDA#821-601-689
Attn: National Asset Management Core Equity Fund
Account name (shareholder name)
Shareholder account number

If you are  making  a  subsequent  purchase,  your  bank  should  wire  funds as
indicated  above.  Before each wire  purchase,  you should be sure to notify the
Transfer  Agent.  It is essential  that your bank include  complete  information
about your account in all wire instructions.  If you have questions about how to
invest by wire, you may call the Transfer Agent.  Your bank may charge you a fee
for sending a wire to the Fund.

THROUGH  FINANCIAL  ADVISORS.  You may buy and sell  shares of the Fund  through
certain  brokers  (and  their  agents,   together   "brokers")  that  have  made
arrangements  with the Fund. An order placed with such a broker is treated as if
it were placed  directly  with the Fund,  and will be executed at the next share
price  calculated by the Fund.  Your shares will be held in a pooled  account in
the  broker's  name,  and the broker will  maintain  your  individual  ownership
information.  The Fund may pay the broker for maintaining  these records as well
as providing other shareholder services. In addition,  the broker may charge you
a fee for handling your order.  The broker is responsible  for  processing  your
order  correctly  and  promptly,  keeping  you  advised  of the  status  of your
individual  account,  confirming your transactions and ensuring that you receive
copies of the Fund's prospectus.

HOW TO SELL SHARES

You may sell  (redeem)  your Fund shares on any day the New York Stock  Exchange
("NYSE")  is open for  business  either  directly  to the Fund or  through  your
investment representative.

REDEMPTIONS  BY MAIL.  You may redeem  your  shares by simply  sending a written
request to the Fund.  You should give your account  number

PROSPECTUS                             8

and state  whether  you want all or some of your  shares  redeemed.  The  letter
should be signed by all of the  shareholders  whose names  appear in the account
registration.  You should send your redemption  request to the Transfer Agent at
the following address:

National Asset Management Core Equity Fund
150 Motor Parkway, Suite 109
Hauppauge, NY 11788

Payment of your redemption proceeds will normally be made promptly, but no later
than  seven  days  after  the  receipt  of a  written  request  that  meets  the
requirements  described  above.  If you  did not  purchase  your  shares  with a
certified  check,  the Fund may delay payment of your redemption  proceeds until
your check has cleared, which may take up to 15 days.

REDEMPTION BY TELEPHONE.  If you complete the Redemption by Telephone portion of
the  Fund's  Application  Form,  you may  redeem  some or all of your  shares by
telephone. You may redeem your shares on any day the NYSE is open by calling the
Fund's  Shareholder  Servicing Agent at (800) 385-7003 before 4:00 p.m., Eastern
time.  Redemption  proceeds  will be mailed  on the next  business  day.  If you
request,  your redemption proceeds will be wired on the next business day to the
bank account you have  designated on the  Application  Form.  The minimum amount
that may be wired is $1,000.  Wire  charges,  if any, will be deducted from your
redemption  proceeds.  You may not use the telephone  redemption  for retirement
accounts.

When you establish  telephone  privileges,  you are authorizing the Fund and its
Transfer Agent to act upon the telephone  instructions  of the person or persons
you have designated in your Application  Form. Such persons may request that the
shares in your account be redeemed.

Before executing an instruction received by telephone, the Fund and the Transfer
Agent  will use  procedures  to  confirm  that the  telephone  instructions  are
genuine.  These procedures will include  recording the telephone call and asking
the caller for a form of personal  identification.  If the Fund and the Transfer
Agent follow these procedures, they will not be liable for any loss, expense, or
cost  arising  out of any  telephone  redemption  or  exchange  request  that is
reasonably believed to be genuine.  This includes any fraudulent or unauthorized
request.

You may have  difficulties  in making a telephone  redemption  during periods of
abnormal  market  activity.  If this should occur,  you may make your redemption
request in writing.

OTHER  REDEMPTION  INFORMATION.  Certain  redemption  requests  require that the
signature  or  signatures  on the account will have to be  guaranteed.  Call the
Transfer Agent at 1-800-385-7003  for further details.  If shares were purchased
by wire,  they cannot be redeemed  until the day after the  Application  Form is
received.

                                       9                              PROSPECTUS

If shares were  purchased by check and then redeemed  shortly after the check is
received,  the Fund may delay sending the redemption  proceeds until it has been
notified  that the check  used to  purchase  the shares  has been  collected,  a
process  which  may  take up to 15  days.  The Fund  may  suspend  the  right of
redemption  under certain  extraordinary  circumstances  in accordance  with the
rules of the Securities and Exchange Commission.

The Fund may redeem the shares in your  account if the value of your  account is
less than $5,000 as a result of redemptions  you have made.  This does not apply
to retirement  plan or Uniform  Gifts or Transfers to Minors Act  accounts.  You
will be notified  that the value of your account is less than $5,000  before the
Fund  makes an  involuntary  redemption.  You will then have 30 days in which to
make an  additional  investment  to bring the value of your  account to at least
$5,000 before the Fund takes any action.

The  Fund  has the  right to pay  redemption  proceeds  in whole or in part by a
distribution  of securities from the Fund's  portfolio.  It is not expected that
the Fund would do so except in unusual circumstances.

PRICING OF FUND SHARES

The price of Fund shares is based on the Fund's net asset  value.  The net asset
value of the Fund's shares is determined  by dividing the Fund's  assets,  minus
its liabilities, by the number of shares outstanding.  The Fund's assets are the
market  value of  securities  held in its  portfolio,  plus  any cash and  other
assets. The Fund's liabilities are fees and expenses it owes. The number of Fund
shares   outstanding  is  the  amount  of  shares  which  have  been  issued  to
shareholders.  The price you will pay to buy Fund  shares or the amount you will
receive  when you sell your Fund  shares  is based on the net asset  value  next
calculated after your order is received and accepted.

The net  asset  value of the  Fund's  shares  is  determined  as of the close of
regular  trading on the NYSE.  This is normally 4:00 p.m.,  Eastern  time.  Fund
shares will not be priced on days that the NYSE is closed for trading.

DISTRIBUTIONS AND TAXES

The Fund will  make  distributions  of  dividends  and  capital  gains,  if any,
annually,  usually  after  the  end  of the  year.  Because  of  its  investment
strategies, the Fund expects that its distributions will consist of both capital
gains and dividends.

You can choose from three distribution  options:  (1) reinvest all distributions
in additional Fund shares; (2) receive  distributions from net investment income
in cash while reinvesting capital gains distributions in additional Fund shares;
or  (3)  receive  all  distributions  in  cash.  If  you  wish  to  change  your
distribution  option,  write to the  Transfer  Agent  before the  payment of the
distribution.  If you do not select an option  when you open your

                                      10                              PROSPECTUS

account, all distributions will be reinvested in Fund shares. You will receive a
statement  confirming  reinvestment of  distributions  in additional Fund shares
promptly following the quarter in which the reinvestment occurs.

If a check  representing  a Fund  distribution  is not cashed within a specified
period,  the  Transfer  Agent  will  notify  you that you  have  the  option  of
requesting  another check or reinvesting  the  distribution  in the Fund. If the
Transfer  Agent  does  not  receive  your  election,  the  distribution  will be
reinvested in the Fund.  Similarly,  if the Fund or the Transfer Agent sends you
correspondence returned as "undeliverable,"  distributions will automatically be
reinvested in the Fund.

TAX CONSEQUENCES

Dividends  are  taxable to you as ordinary  income.  The rate you pay on capital
gain  distributions  will depend on how long the Fund held the  securities  that
generated  the gains,  not on how long you owned your Fund  shares.  You will be
taxed in the same manner  whether you receive  your  dividends  and capital gain
distributions in cash or reinvest them in additional Fund shares.

If you sell  your  Fund  shares,  it is  considered  a  taxable  event  for you.
Depending on the purchase  price and the sale price of the shares you sell,  you
may have a gain or a loss on the  transaction.  You are  responsible for any tax
liabilities generated by your transaction.

                                      11                              PROSPECTUS

                   NATIONAL ASSET MANAGEMENT CORE EQUITY FUND,
                        A SERIES OF ADVISORS SERIES TRUST

For investors who want more information  about the Fund, the following  document
is available free upon request:

Statement  of  Additional  Information  (SAI):  The SAI provides  more  detailed
information about the Fund and is incorporated into this prospectus.

You can get free copies of the SAI,  request other  information and discuss your
questions about the Fund by contacting the Fund at:

                   National Asset Management Core Equity Fund
                       400 West Market Street, Suite 2500
                              Louisville, KY 40202
                                 1-877-626-3863

You can  review  and copy  information  including  the  Fund's SAI at the Public
Reference Room of the Securities and Exchange Commission in Washington, D.C. You
can obtain  information on the operation of the Public Reference Room by calling
1-800-SEC-0330. You can get text-only copies for a fee, by writing to the Public
Reference  Room of the  Commission,  Washington,  DC  20549-6009  or by  calling
1-800-SEC-0330  or free of charge  from the  Commission's  Internet  website  at
www.sec.gov.

                                          The Fund's SEC File Number is 811-0959