RBB FUND INC, 497, 1998-07-20

RBB FUND INC
497, 1998-07-20

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PROSPECTUS
JULY 1, 1998

BOSTON PARTNERS
MICRO CAP
VALUE FUND
(INSTITUTIONAL SHARES)

[LOGO OMITTED]

bp
BOSTON PARTNERS ASSET MANAGEMENT, L.P.

<PAGE>

BOSTON PARTNERS MICRO CAP VALUE FUND
(INSTITUTIONAL CLASS)
OF
THE RBB FUND, INC.

Boston Partners Micro Cap Value Fund (the "Fund") is an investment
portfolio of The RBB Fund, Inc. ("RBB"), an open-end management investment
company. The shares of the Institutional Class ("Shares") offered by this
Prospectus represent interests in the Fund. The Fund is a diversified fund that
seeks long-term growth of capital, with current income as a secondary objective,
primarily through equity investments, such as common stocks. It seeks to achieve
its objectives by investing at least 65% of its total assets in a diversified
portfolio consisting of equity securities of issuers with market capitalizations
that do not exceed $500 million when purchased by the Fund, and identified by
Boston Partners Asset Management, L.P. (the "Adviser") as equity securities that
it believes possess value characteristics. The Adviser examines various factors
in determining the value characteristics of such issuers, including, but not
limited to, price to book value ratios and price to earnings ratios. These value
characteristics are examined in the context of the issuer's operating and
financial fundamentals such as return on equity, earnings growth and cash flow.

This Prospectus contains information that a prospective investor needs to
know before investing. Please keep it for future reference. A Statement of
Additional Information, dated July 1, 1998, has been filed with the Securities
and Exchange Commission and is incorporated by reference in this Prospectus. It
may be obtained free of charge from the Fund by calling (888) 261-4073. The
Prospectus and the Statement of Additional Information are available for
reference, along with other related materials, on the SEC Internet Web Site
(http://www.sec.gov).

SHARES OF THE FUND ARE NOT DEPOSITS OR OBLIGATIONS OF OR GUARANTEED OR ENDORSED
BY PNC BANK, NATIONAL ASSOCIATION OR ANY OTHER BANK AND SHARES ARE NOT FEDERALLY
INSURED BY THE FEDERAL DEPOSIT INSURANCE CORPORATION, THE FEDERAL RESERVE BOARD
OR ANY OTHER AGENCY. INVESTMENTS IN SHARES OF THE FUND INVOLVE INVESTMENT RISKS,
INCLUDING THE POSSIBLE LOSS OF PRINCIPAL.

- --------------------------------------------------------------------------------
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE COMMISSION OR
ANY STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
- --------------------------------------------------------------------------------

PROSPECTUS July 1, 1998

<PAGE>

EXPENSE TABLE
- --------------------------------------------------------------------------------
The following table illustrates the shareholder transaction and annual
operating expenses that are expected to be incurred by Institutional Shares of
the Fund (after fee waivers and expense reimbursements) during the next twelve
months as a percentage of average daily net assets. An example based on the
summary is also shown.

SHAREHOLDER TRANSACTION EXPENSES

Maximum Sales Charge Imposed on Purchases ........................... None

Maximum Sales Charge Imposed on Reinvested Dividends ................ None

Maximum Deferred Sales Charge ....................................... None

Redemption Fee(1) ................................................... 1.00%

Exchange Fee ........................................................ None

ANNUAL FUND OPERATING EXPENSES (AS A PERCENTAGE OF AVERAGE NET ASSETS)

Management Fees (after waivers)(2) .................................. 0.00%

12b-1 Fees .......................................................... None

Other Expenses (after expense reimbursements)(2) .................... 1.55%
-----

Total Fund Operating Expenses (after waivers
and expense reimbursements)(2) ................................... 1.55%
=====

(1) To prevent the Fund from being adversely affected by the transaction costs
associated with short-term shareholder transactions, the Fund will redeem
shares at a price equal to the net asset value of the shares, less an
additional transaction fee equal to 1.00% of the net asset value of all
such shares redeemed that have been held for less than one year. Such fees
are not sales charges or contingent deferred sales charges, but are
retained by the Fund to cover brokerage and other market impact costs
associated with such redemptions.

(2) In the absence of fee waivers and expense reimbursements, Management Fees
would be 1.25%, Other Expenses would be 2.15%, and Total Fund Operating
Expenses would be 3.40%. Management Fees are based on average daily net
assets and are calculated daily and paid monthly.

EXAMPLE

An investor would pay the following expenses on a $1,000 investment in the
Fund, assuming (1) a 5% annual return and (2) redemption at the end of each time
period (including the 1.00% transaction fee on redemptions made within a year of
purchase):
ONE THREE
YEAR YEARS
---- -----
Boston Partners Micro Cap Value Fund .............. $16 $49

The Fee Table is designed to assist an investor in understanding the
various costs and expenses that an investor in the Fund will bear directly or
indirectly. (For more complete descriptions of the various costs and expenses,
see "Management" below.) The Fee Table reflects expense reimbursements and
voluntary waivers of Management Fees for the Fund, which are expected to be in
effect during the current fiscal year. However, the Adviser, and the Fund's
other service providers are under no obligation with respect to such expense
reimbursements and waivers and there can be no assurance that any future expense
reimbursements and waivers of Management Fees will not vary from the figures
reflected in the Fee Table.

<PAGE>

The Example in the Fee Table assumes that all dividends and distributions
are reinvested and that the amounts listed under "Annual Fund Operating
Expenses" remain the same in the years shown. THE EXAMPLE SHOULD NOT BE
CONSIDERED A REPRESENTATION OF PAST OR FUTURE EXPENSES AND ACTUAL EXPENSES MAY
BE GREATER OR LESS THAN THOSE SHOWN.

INTRODUCTION
- --------------------------------------------------------------------------------
RBB is an open-end management investment company incorporated under the
laws of the State of Maryland currently operating or proposing to operate
twenty-six separate investment portfolios. The Shares offered by this Prospectus
represent interests in the Boston Partners Micro Cap Value Fund. RBB was
incorporated in Maryland on February 29, 1988.

INVESTMENT OBJECTIVES AND POLICIES
- --------------------------------------------------------------------------------
The Fund's investment objective is to provide long-term growth of capital,
with current income as a secondary objective, primarily through equity
investments, such as common stocks. The Fund seeks to achieve its objective by
investing, under normal market conditions, at least 65% of its total assets in a
diversified portfolio consisting primarily of equity securities of issuers with
market capitalizations that do not exceed $500 million when purchased by the
Fund, and identified by the Adviser as equity securities that possess value
characteristics.

The Fund generally invests in the equity securities of small companies. The
Adviser will seek to invest in companies it considers to be well managed and to
have attractive fundamental financial characteristics. The Adviser believes
greater potential for price appreciation exists among small companies since they
tend to be less widely followed by other securities analysts and thus may be
more likely to be undervalued by the market. The Fund may invest from time to
time a portion of its assets, not to exceed 35% (under normal conditions) at the
time of purchase, in companies with considerably larger market capitalizations.

The Fund presents greater risks than funds that invest in equity securities
of larger companies for the following reasons: Companies in which the Fund
primarily invests will include those that have limited product lines, markets,
or financial resources, or are dependent upon a small management group. In
addition, because these stocks are not well known to the investing public, do
not have significant institutional ownership, and are followed by relatively few
securities analysts, there will normally be less publicly available information
concerning these securities compared to what is available for the securities of
larger companies. Adverse publicity and investor perceptions, whether or not
based on fundamental analysis, can decrease the value and liquidity of
securities held by the Fund. Historically, small capitalization stocks have been
more volatile in price than larger capitalization stocks. Among the reasons for
the greater price volatility of these small company stocks are the less certain
growth prospects of smaller firms, the lower degree of liquidity in the markets
for such stocks, the greater sensitivity of small companies to changing economic
conditions, the fewer market makers and the wider spreads between quoted bid and
asked prices which exist in the over-the-counter market for such stocks. Besides
exhibiting greater volatility, small company stocks may, to a degree, fluctuate
independently of larger company stocks. Small company stocks may decline in
price as large company stocks rise, or rise in price as large company stocks
decline. Investors should therefore expect that the Fund will be more volatile
than, and may fluctuate independently of, broad stock market indices such as the
Standard & Poor's 500 Composite Stock Price Index.

<PAGE>

Fund to dispose of a substantial block of such securities. The disposition by
the Fund of portfolio securities to meet redemptions or otherwise may require
the Fund to sell these securities at a discount from market prices or during
periods when, in the Adviser's judgment, such disposition is not desirable or to
make many small sales over a lengthy period of time.

The Adviser examines various factors in determining the value
characteristics of such issuers, including, but not limited to, price to book
value ratios and price to earnings ratios. These value characteristics are
examined in the context of the issuer's operating and financial fundamentals
such as return on equity, earnings growth and cash flow.

The Adviser selects securities for the Fund based on a fundamental analysis
of industries and companies, earning power and growth and other investment
criteria. In general, the Fund's investments are broadly diversified over a
number of industries and, as a matter of policy, the Fund will not invest 25% or
more of its total assets in any one industry.

The Fund may invest up to 25% of its total assets in securities of foreign
issuers, including American Depository Receipts ("ADRs") and European Depository
Receipts ("EDRs"). Investing in securities of foreign issuers involves
considerations not typically associated with investing in securities of
companies organized and operating in the United States. Foreign securities
generally are denominated and pay dividends or interest in foreign currencies.
The Fund may hold from time to time various foreign currencies pending their
investment in foreign securities or their conversion into U.S. dollars. The
value of the assets of the Fund as measured in U.S. dollars may therefore be
affected favorably or unfavorably by changes in exchange rates. There may be
less publicly available information concerning foreign issuers than is available
with respect to U.S. issuers. Foreign securities may not be registered with the
U.S. Securities and Exchange Commission, and generally, foreign companies are
not subject to uniform accounting, auditing and financial reporting requirements
comparable to those applicable to U.S. issuers. ADRs and EDRs are receipts
issued by a U.S. bank or trust company evidencing ownership of underlying
securities issued by a foreign issuer. ADRs and EDRs may be listed on a national
securities exchange or may trade in the over-the-counter market. ADR and EDR
prices are denominated in U.S. dollars, even though the underlying security may
be denominated in a foreign currency. The underlying security may be subject to
foreign government taxes which would reduce the yield on such securities.
Investments in such instruments involve risks similar to those of investing
directly in foreign securities. See "Investment Objectives and Policies--Foreign
Securities" in the Statement of Additional Information.

The Fund may invest the remainder of its total assets in derivative
securities; debt securities issued by U.S. banks, corporations and other
business organizations that are investment grade securities; and debt securities
issued by the U.S. government or government agencies.

In accordance with the above-mentioned policies, the Fund may also invest
in indexed securities, repurchase agreements, reverse repurchase agreements,
dollar rolls, financial futures contracts, options on futures contracts and may
lend portfolio securities. See "Investment Objectives and Policies" in the
Statement of Additional Information.

The Fund may invest in registered investment companies and investment funds
in foreign countries subject to the provisions of the Investment Company Act of
1940, as amended (the "1940 Act"), and as discussed in "Investment Objectives
and Policies" in the Statement of Additional Information. If the Fund invests in
such investment companies, the Fund will bear its proportionate share of the
costs incurred by such companies, including investment advisory fees.

While the Adviser intends to fully invest the Fund's assets at all times in
accordance with the above-mentioned policies, the Fund reserves the right to
hold up to 100% of its assets, as a temporary defensive measure, in cash and
eligible U.S. dollar-denominated money market instruments. The Adviser would
determine when market conditions warrant temporary defensive measures.

The Fund's investment objective and the policies described above may be
changed by RBB's Board of Directors without the affirmative vote of the holders
of a majority of the outstanding Shares representing interests in the Fund.

<PAGE>

INVESTMENT LIMITATIONS
- --------------------------------------------------------------------------------

The Fund may not change the following investment limitations without
shareholder approval. (A complete list of the investment limitations that cannot
be changed without such a vote of the shareholders is contained in the Statement
of Additional Information under "Investment Objectives and Policies.")

The Fund may not:

1. Purchase the securities of any one issuer, other than securities
issued or guaranteed by the U.S. Government or its agencies or
instrumentalities, if immediately after and as a result of such purchase
more than 5% of the value of the Fund's total assets would be invested in
the securities of such issuer, or more than 10% of the outstanding voting
securities of such issuer would be owned by the Fund, except that up to 25%
of the value of the Fund's total assets may be invested without regard to
such limitations.

2. Purchase any securities which would cause, at the time of purchase,
25% or more of the value of the total assets of the Fund to be invested in
the obligations of issuers in any single industry, provided that there is
no limitation with respect to investments in U.S. Government obligations.

3. Borrow money or issue senior securities, except that the Fund may
borrow from banks and enter into reverse repurchase agreements and dollar
rolls for temporary purposes in amounts up to one-third of the value of its
total assets at the time of such borrowing; or mortgage, pledge or
hypothecate any assets, except in connection with any such borrowing and
then in amounts not in excess of one-third of the value of the Fund's total
assets at the time of such borrowing. The Fund will not purchase securities
while its aggregate borrowings (including reverse repurchase agreements,
dollar rolls and borrowings from banks) are in excess of 5% of its total
assets. Securities held in escrow or separate accounts in connection with
the Fund's investment practices are not considered to be borrowings or
deemed to be pledged for purposes of this limitation.

Except as required by the 1940 Act with respect to the borrowing of money,
if a percentage restriction is satisfied at the time of investment, a later
increase or decrease in percentage resulting from a change in values will not
constitute a violation of that restriction.

PORTFOLIO TURNOVER

The Fund retains the right to sell securities irrespective of how long they
have been held. The Adviser estimates that the annual turnover in the Fund will
not exceed 150%. Such a relatively high portfolio turnover will be accompanied
by relatively high transactional (i.e., brokerage) costs. It may also result in
increased capital gains realized by the Fund and distributed to shareholders.

RISK FACTORS
- --------------------------------------------------------------------------------
As with other mutual funds, there can be no assurance that the Fund will
achieve its objective. The net asset value per share of Shares representing an
interest in the Fund will fluctuate as the values of its portfolio securities
change in response to changing conditions in the equity market. An investment in
the Fund is not intended to constitute a balanced investment program. As of the
date of this Prospectus, U.S. stock markets were trading at or close to record
high levels and there can be no guarantee that such levels will continue. Other
risk factors are discussed above under "Investment Objectives and Policies" and
in the Statement of Additional Information under "Investment Objectives and
Policies."

Investment methods described in this Prospectus are among those which the
Fund has the power to utilize. Some may be employed on a regular basis; others
may not be used at all. Accordingly, reference to any particular method or
technique carries no implication that it will be utilized or, if it is, that it
will be successful.

<PAGE>

MANAGEMENT
- --------------------------------------------------------------------------------
BOARD OF DIRECTORS

The business and affairs of RBB and the Fund are managed under the
direction of RBB's Board of Directors.

INVESTMENT ADVISER

Boston Partners Asset Management, L.P., located at Boston, Massachusetts,
serves as the Fund's investment adviser. The Adviser provides investment
management and investment advisory services to investment companies and other
institutional accounts that had aggregate total assets under management as of
March 31, 1998, in excess of $15 billion. The adviser is organized as a Delaware
limited partnership whose sole general partner is Boston Partners, Inc., a
Delaware corporation.

Subject to the supervision and direction of the Trust's Board of Trustees,
the Adviser manages the Fund's portfolio in accordance with the Fund's
investment objective and policies, makes investment decisions for the Fund,
places orders to purchase and sell securities, and employs professional
portfolio managers and securities analysts who provide research services to the
Fund. For its services to the Fund, the Adviser is paid a monthly advisory fee
computed at an annual rate of 1.25% of the Fund's average daily net assets. The
Adviser has notified RBB, however, that it expects to waive all advisory fees
during the current fiscal year.

PORTFOLIO MANAGEMENT

The day-to-day portfolio management of the Fund is the responsibility of
David M. Dabora and Wayne J. Archambo who are portfolio managers of the Adviser.
Prior to taking on day to day responsibilities for the Micro Cap Value Fund, Mr.
Dabora was an assistant portfolio manager/analyst of the premium equity product
of the Adviser, an all-cap value institutional product. Before joining the
Adviser in April 1995, Mr. Dabora had been employed by The Boston Company Asset
Management, Inc. since 1991 as a senior equity analyst. Mr. Dabora has over 10
years of investment experience and is a Chartered Financial Analyst. Mr.
Archambo oversees the investment activities of the Adviser's $900 million of
mid-capitalization value equity product (including the $56 million Mid Cap Value
Fund) and the $1.2 billion small-capitalization value institutional equity
product. Prior to joining the Adviser in April 1995, Mr. Archambo had been
employed by The Boston Company Asset Management, Inc. since 1989 as a senior
portfolio manager and a member of that firm's Equity Policy Committee. Mr.
Archambo has over 15 years of investment experience and is a Chartered Financial
Analyst.

ADMINISTRATOR

PFPC Inc. ("PFPC") serves as administrator to the Fund and generally
assists the Fund in all aspects of its administration and operations, including
matters relating to the maintenance of financial records and accounting. For its
services, PFPC receives a fee calculated at an annual rate of .125% of the
Fund's average daily net assets, with a minimum annual fee of $75,000 payable
monthly on a pro rata basis. PFPC has notified the Fund that it intends to waive
one-half of its minimum annual fee during the current fiscal year.

DISTRIBUTOR

Provident Distributors, Inc. ("PDI"), with a principal business address at
Four Falls Corporate Center, 6th Floor, West Conshohocken, Pennsylvania 19428,
acts as distributor for the Shares pursuant to a distribution agreement (the
"Distribution Agreement") with RBB on behalf of the Shares.

ADMINISTRATIVE SERVICES AGENT

PDI acts as Administrative Services Agent to the Fund with respect to its
Institutional Class shares, providing certain administrative services to such
Class that are not provided by PFPC. These services include furnishing corporate
secretarial, data processing and clerical services, acting as liaison between
the Fund's Institutional Class shares

<PAGE>

and the Fund's various service providers, furnishing corporate secretarial
services, which include assisting in the coordination and preparation of reports
to shareholders including proxy statements and annual, semi-annual and quarterly
reports and generally assisting in monitoring and developing compliance
procedures for the Fund. As compensation for such administrative services, PDI
is entitled to a monthly fee calculated at the annual rate of .15% of the Fund's
Institutional Class's average daily net assets.

TRANSFER AGENT, DIVIDEND DISBURSING AGENT, AND CUSTODIAN

EXPENSES

The expenses of the Fund are deducted from its total income before
dividends are paid. Any general expenses of RBB that are not readily
identifiable as belonging to a particular investment portfolio of RBB will be
allocated among all investment portfolios of RBB based upon the relative net
assets of the investment portfolios. The Institutional Class of the Fund pays
its own distribution fees, if any, and may pay a different share of other
expenses than other classes (excluding advisory and custodial fees) if those
expenses are actually incurred in a different amount by the Institutional Class
or if it receives different services.

The Adviser may assume expenses of the Fund from time to time. To the
extent any service providers assume expenses of the Fund, such assumption of
expenses will have the effect of lowering the Fund's overall expense ratio and
increasing its yield to investors.

HOW TO PURCHASE SHARES
- --------------------------------------------------------------------------------
GENERAL

Shares representing an interest in the Fund are offered continuously for
sale by the Distributor. Shares may be purchased initially by completing the
application included in this Prospectus and forwarding the application to the
Fund's transfer agent, PFPC. Purchases of Shares may be effected by wire to an
account to be specified by PFPC or by mailing a check or Federal Reserve Draft,
payable to the order of "The Boston Partners Micro Cap Value Fund," c/o PFPC
Inc., P.O. Box 8852, Wilmington, Delaware 19899-8852. The name of the Fund,
Boston Partners Micro Cap Value Fund, must also appear on the check or Federal
Reserve Draft. Shareholders may not purchase shares of the Boston Partners Micro
Cap Value Fund with a check issued by a third party and endorsed over to the
Fund. Federal Reserve Drafts are available at national banks or any state bank
which is a member of the Federal Reserve System. Initial investments in the Fund
must be at least $100,000 and subsequent investments must be at least $5,000.
For purposes of meeting the minimum initial purchase, clients which are part of
endowments, foundation or other related groups may be aggregated. The Fund
reserves the right to suspend the offering of Shares for a period of time or to
reject any purchase order. As of the date of this Prospectus, the Fund intends
to suspend the offering of Shares upon the Fund's attaining $300 million in
total assets.

Shares may be purchased on any Business Day. A "Business Day" is any day
that the New York Stock Exchange, Inc. (the "NYSE") is open for business.
Currently, the NYSE is closed on weekends and New Year's Day, Dr. Martin Luther
King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Independence Day,
Labor Day, Thanksgiving Day and Christmas Day and on the preceding Friday or
subsequent Monday when one of these holidays falls on a Saturday or Sunday.

<PAGE>

The price paid for Shares purchased is based on the net asset value next
computed after a purchase order is received by the Fund or its agents prior to
close of the NYSE on such day (generally 4:00 p.m. Eastern Time). Orders
received by the Fund or its agents after the close of the NYSE are priced at the
net asset value next determined on the following Business Day. In those cases
where an investor pays for Shares by check, the purchase will be effected at the
net asset value next determined after the Fund or its agents receives the order
and the completed application.

Shares may be purchased and subsequent investments may be made by
principals and employees of the Adviser, and by their spouses and children,
either directly or through their individual retirement accounts, trusts or other
such vehicles, and by any pension and profit-sharing plan of the Adviser (or any
person having a relationship with such plans), without being subject to the
minimum investment limitations.

An investor may also purchase Shares by having his bank or his broker wire
Federal Funds to PFPC. An investor's bank or broker may impose a charge for this
service. The Fund does not currently impose a service charge for effecting wire
transfers but reserves the right to do so in the future. In order to ensure
prompt receipt of an investor's Federal Funds wire for an initial investment, it
is important that an investor follows these steps:

A. Telephone the Fund's transfer agent, PFPC, toll-free (888) 261-4073,
and provide PFPC with your name, address, telephone number, Social Security
or Tax Identification Number, the Fund selected, the amount being wired,
and by which bank. PFPC will then provide an investor with a Fund account
number. Investors with existing accounts should also notify PFPC prior to
wiring funds.

B. Instruct your bank or broker to wire the specified amount, together
with your assigned account number, to PFPC's account with PNC:

PNC Bank, N.A.
Philadelphia, PA 19103
ABA NUMBER: 0310-0005-3
CREDITING ACCOUNT NUMBER: 86-1108-2507
FROM: (name of investor)
ACCOUNT NUMBER: (Investor's account number with the Fund)
FOR PURCHASE OF: (name of the Fund)
AMOUNT: (amount to be invested)

C. Fully complete and sign the application and mail it to the address
shown thereon. PFPC will not process purchases until it receives a fully
completed and signed application.

For subsequent investments, an investor should follow steps A and B above.

AUTOMATIC INVESTING

Additional investments in Shares may be made automatically by authorizing
the Fund's transfer agent to withdraw funds from your bank account. Investors
desiring to participate in the automatic investing program should call the
Fund's transfer agent, PFPC, at (888) 261-4073 to obtain the appropriate forms.

HOW TO REDEEM AND EXCHANGE SHARES
- --------------------------------------------------------------------------------
REDEMPTION BY MAIL

Shareholders may redeem for cash some or all of their Shares of the Fund at
any time. To do so, a written request in proper form must be sent directly to
Boston Partners Micro Cap Value Fund, c/o PFPC Inc., P.O. Box 8852, Wilmington,
Delaware 19899-8852. There is no charge for a redemption, unless the Shareholder
has held his or her Shares for less than one year, upon which a fee equal to 1%
of the net asset value of the Shares redeemed at the time of redemption will be
imposed.

<PAGE>

[THIS PAGE INTENTIONALLY LEFT BLANK]

<PAGE>

BOSTON PARTNERS MICRO CAP VALUE FUND bp
(INSTITUTIONAL CLASS) BOSTON PARTNERS ASSET MANAGEMENT, L.P.

ACCOUNT APPLICATION
PLEASE NOTE: Do not use this form to open a retirement plan account. For an IRA
application or help with this Application, please call 1-888-261-4073

+--------------+ (Please check the appropriate box(es) below.)
| 1 | [ ] Individual [ ] Joint Tenant [ ] Other
| Account |
| Registration:| --------------------------------------------------------------
+--------------+ Name SOCIAL SECURITY NUMBER OR TAX ID #
OF PRIMARY OWNER

--------------------------------------------------------------
NAME OF JOINT OWNER JOINT OWNER SOCIAL SECURITY
NUMBER OR TAX ID #

For joint accounts, the account registrants will be joint
tenants with right of survivorship and not tenants in common
unless tenants in common or community property registrations
are requested.

- -------------
GIFT TO MINOR: [ ] UNIFORM GIFTS/TRANSFER TO MINOR'S ACT
- -------------
--------------------------------------------------------------
NAME OF ADULT CUSTODIAN (ONLY ONE PERMITTED)

--------------------------------------------------------------
NAME OF MINOR (ONLY ONE PERMITTED)

--------------------------------------------------------------
MINOR'S SOCIAL SECURITY NUMBER AND DATE OF BIRTH

- ------------------
CORPORATION,
PARTNERSHIP, TRUST
OR OTHER ENTITY:
- ------------------
--------------------------------------------------------------
NAME OF CORPORATION, PARTNERSHIP, NAME(S) OF TRUSTEE(S)
OR OTHER

--------------------------------------------------------------
TAXPAYER IDENTIFICATION NUMBER

+--------------+ --------------------------------------------------------------
| 2 | STREET OR P.O. BOX AND/OR APARTMENT NUMBER
| Mailing |
| Address: | --------------------------------------------------------------
+--------------+ CITY STATE ZIP CODE

--------------------------------------------------------------
DAY PHONE NUMBER EVENING PHONE NUMBER

+--------------+
| 3 | Minimum initial investment Amount of investment $______
| Investment | of $100,000.
| Information: |
+--------------+ Make the check payable to Boston Partners
Micro Cap Value Fund.

Shareholders may not purchase shares of this Fund with a check
issued by a third party and endorsed over to the Fund.

- ------------
DISTRIBUTION NOTE: Dividends and capital gains may be reinvested or paid by
OPTIONS: check. If no options are selected below, both dividends and
- ------------ capital gains will be reinvested in additional Fund shares.

DIVIDENDS [ ] Pay by check [ ] Reinvest [ ]
CAPITAL GAINS [ ] Pay by check [ ] Reinvest [ ]

+--------------+ To use this option, you must initial the appropriate line
| 4 | below.
| Telephone | I authorize the Transfer Agent to accept instructions from
| Redemption: | any persons to redeem or exchange shares in my account(s) by
+--------------+ telephone in accordance with the procedures and conditions set
set forth in the Fund's current prospectus.

Redeem shares, and send
------------------ ------------- the proceeds to the
individual initial joint initial address of record.

Exchange shares for
------------------ ------------- shares of The Boston
individual initial joint initial Partners Large Cap
Value Fund, Boston
Partners Mid Cap Value
Fund or Boston Partners
Bond Fund.

+--------------+ The Automatic Investment Plan which is available to
| 5 | shareholders of the Fund, makes possible regularly scheduled
| Automatic | purchases of Fund shares to allow dollar-cost averaging. The
| Investment | Fund's Transfer Agent can arrange for an amount of money
| Plan: | selected by you to be deducted from your checking account and
+--------------+ used to purchase shares of the Fund.

Please debit $________ from my checking account (named below
on or about the 20th of the month. PLEASE ATTACH AN UNSIGNED,
VOIDED CHECK.
[ ] Monthly [ ] Every Alternate Month [ ] Quarterly [ ] Other

- --------------- --------------------------------------------------------------
BANK OF RECORD: BANK NAME STREET ADDRESS OR P.O. BOX
- ---------------
--------------------------------------------------------------
CITY STATE ZIP CODE

--------------------------------------------------------------
BANK ABA NUMBER BANK ACCOUNT NUMBER

+--------------+ The undersigned warrants that I (we) have full authority and,
| 6 | if a natural person, I (we) am (are) of legal age to purchase
| Signatures: | shares pursuant to this Account Application, and I (we) have
+--------------+ received a current prospectus for the Fund in which I (we) am
(are) investing.
Under the Interest and Dividend Tax Compliance Act of 1983,
the Fund is required to have the following certification:
Under penalties of perjury, I certify that:
(1) The number shown on this form is my correct taxpayer
identification number (or I am waiting for a number to be
issued to), and
(2) I am not subject to backup withholding because (a) I am
exempt from backup withholding, or (b) I have not been
notified by the Internal Revenue Service that I am subject to
31% backup withholding as a result of a failure to report all
interest or dividends, or (c) the IRS has notified me that I
am no longer subject to backup withholding.

NOTE: YOU MUST CROSS OUT ITEM (2) ABOVE IF YOU HAVE BEEN
NOTIFIED BY THE IRS THAT YOU ARE CURRENTLY SUBJECT TO BACKUP
WITHHOLDING BECAUSE YOU HAVE FAILED TO REPORT ALL INTEREST AND
DIVIDENDS ON YOUR TAX RETURN. THE INTERNAL REVENUE SERVICE
DOES NOT REQUIRE YOUR CONSENT TO ANY PROVISION OF THIS
DOCUMENT OTHER THAN THE CERTIFICATION REQUIRED TO AUDIT BACKUP
WITHHOLDING.

--------------------------------------------------------------
SIGNATURE OF APPLICANT DATE

--------------------------------------------------------------
PRINT NAME TITLE (IF APPLICABLE)

--------------------------------------------------------------
SIGNATURE OF JOINT OWNER DATE

--------------------------------------------------------------
PRINT NAME TITLE (IF APPLICABLE)

(If you are signing for a corporation, you must indicate
corporate office or title. If you wish additional signatories
on the account, please include a corporate resolution. If
signing as a fiduciary, you must indicate capacity.)

For information on additional options, such as IRA
Applications, rollover requests for qualified retirement
plans, or for wire instructions, please call us at
1-888-261-4073.

MAIL COMPLETED THE BOSTON PARTNERS MICRO CAP VALUE FUND
ACCOUNT APPLICATION C/O PFPC INC.
AND CHECK TO: P.O. BOX 8852
WILMINGTON, DE 19899-8852

<PAGE>

[THIS PAGE INTENTIONALLY LEFT BLANK]

<PAGE>

A request for redemption must be signed by all persons in whose names the
Shares are registered. Signatures must conform exactly to the account
registration. If the proceeds of the redemption would exceed $10,000, or if the
proceeds are not to be paid to the record owner at the record address, or if the
shareholder is a corporation, partnership, trust or fiduciary, signature(s) must
be guaranteed according to the procedures described below under "Exchange
Privilege."

Generally, a properly signed written request with any required signature
guarantee is all that is required for a redemption. In some cases, however,
other documents may be necessary. In the case of shareholders holding share
certificates, the certificates for the shares being redeemed must accompany the
redemption request. Additional documentary evidence of authority is also
required by the Fund's transfer agent in the event redemption is requested by a
corporation, partnership, trust, fiduciary, executor or administrator.

TRANSACTION FEE IMPOSED ON CERTAIN REDEMPTIONS

The Fund requires the payment of a transaction fee on redemptions of Shares
of the Fund held for less than one year equal to 1.00% of the net asset value of
such Shares redeemed at the time of redemption. This additional transaction fee
is paid to the Fund, NOT to the adviser, distributor or transfer agent. It is
NOT a sales charge or a contingent deferred sales charge. The fee does not apply
to redeemed Shares that were purchased through reinvested dividends or capital
gain distributions. The purpose of the additional transaction fee is to
indirectly allocate transaction costs associated with redemptions to those
investors making redemptions after holding their shares for a short period, thus
protecting existing shareholders. These costs include: (1) brokerage costs; (2)
market impact costs -- i.e., the decrease in market prices which may result when
the Fund sells certain securities in order to raise cash to meet the redemption
request; (3) the realization of capital gains by the other shareholders in the
Fund; and (4) the effect of the "bid-ask" spread in the over-the-counter market.
The 1.00% amount represents the Fund's estimate of the brokerage and other
transaction costs which may be incurred by the Fund in disposing of stocks in
which the Fund may invest. Without the additional transaction fee, the Fund
would generally be selling its shares at a price less than the cost to the Fund
of acquiring the portfolio securities necessary to maintain its investment
characteristics, resulting in reduced investment performance for all
shareholders in the Fund. With the additional transaction fee, the transaction
costs of selling additional stocks are not borne by all existing shareholders,
but the source of funds for these costs is the transaction fee paid by those
investors making redemptions.

INVOLUNTARY REDEMPTION

The Fund reserves the right to redeem a shareholder's account at any time
the net asset value of the account falls below $500 as the result of a
redemption or an exchange request.

Shareholders will be notified in writing that the value of their account is
less than $500 and will be allowed 30 days to make additional investments before
the redemption is processed.

PAYMENT OF REDEMPTION PROCEEDS

With the exception of redemptions to which the 1.00% transaction fee
applies, the redemption price is the net asset value per share next determined
after the request for redemption is received in proper form by the Fund or its
agents. For redemptions to which the additional transaction fee applies, the
redemption price is the net asset value per share next determined after the
request for redemption is received in proper form by the Fund or its agents,
less an amount equal to 1.00% of the net asset value of such Shares redeemed
that the shareholder has held for less than one year. Payment for Shares
redeemed is made by check mailed within seven days after acceptance by the Fund
or its agents of the request and any other necessary documents in proper order.
Such payment may be postponed or the right of redemption suspended as provided
by the 1940 Act. If the Shares to be redeemed have been recently purchased by
check, the Fund's transfer agent may delay mailing a redemption check, which may
be a period of up to 15 days from the purchase date, pending a determination
that the check has cleared. The Fund has elected to be governed by Rule 18f-1
under the 1940 Act so that a portfolio is obligated to redeem its shares solely
in cash up to the lesser of $250,000 or 1% of its net asset value during any
90-day period for any one shareholder of a portfolio.

<PAGE>

EXCHANGE PRIVILEGE

The exchange privilege is available to shareholders residing in any state
in which the Shares being acquired may be legally sold. A shareholder may
exchange Shares of the Fund for Institutional Shares of the Boston Partners
Large Cap Value Fund, Boston Partners Mid Cap Value Fund or Boston Partners Bond
Fund up to six (6) times per year. Such exchange will be effected at the net
asset value of the exchanged Fund and the net asset value of the Boston Partners
Large Cap Value Fund, Boston Partners Mid Cap Value Fund or Boston Partners Bond
Fund next determined after PFPC's receipt of a request for an exchange. An
exchange of Shares will be treated as a sale for federal income tax purposes.
See "Taxes." A shareholder wishing to make an exchange may do so by sending a
written request to PFPC.

If the exchanging shareholder does not currently own Institutional Shares
of the Boston Partners Large Cap Value Fund, Boston Partners Mid Cap Value Fund
or Boston Partners Bond Fund, a new account will be established with the same
registration, dividend and capital gain options as the account from which shares
are exchanged, unless otherwise specified in writing by the shareholder with all
signatures guaranteed. A signature guarantee may be obtained from a domestic
bank or trust company, broker, dealer, clearing agency or savings association
who are participants in a medallion program recognized by the Securities
Transfer Association. The three recognized medallion programs are Securities
Transfer Agents Medallion Program (STAMP), Stock Exchanges Medallion Program
(SEMP) and New York Stock Exchange, Inc. Medallion Signature Program (MSP).
Signature guarantees that are not part of these programs will not be accepted.
The exchange privilege may be modified or terminated at any time, or from time
to time, by RBB, upon 60 days' written notice to shareholders.

If an exchange is to a new account in the Boston Partners Large Cap Value
Fund, Boston Partners Mid Cap Value Fund or Boston Partners Bond Fund, the
dollar value of Institutional Shares acquired must equal or exceed that Fund's
minimum for a new account; if to an existing account, the dollar value must
equal or exceed that Fund's minimum for subsequent investments. If any amount
remains in the Fund from which the exchange is being made, such amount must not
drop below the minimum account value required by the Fund.

EXCHANGE PRIVILEGE LIMITATIONS

The Fund's exchange privilege is not intended to afford shareholders a way
to speculate on short-term movements in the market. Accordingly, in order to
prevent excessive use of the exchange privilege that may potentially disrupt the
management of the Fund and increase transactions costs, the Fund has established
a policy of limiting excessive exchange activity.

Shareholders are entitled to six (6) exchange redemptions (at least 30 days
apart) from the Fund during any twelve-month period. Notwithstanding these
limitations, the Fund reserves the right to reject any purchase request
(including exchange purchases from the Boston Partners Large Cap Value Fund,
Boston Partners Mid Cap Value Fund and Boston Partners Bond Fund) that is deemed
to be disruptive to efficient portfolio management.

TELEPHONE TRANSACTIONS

In order to request a telephone exchange or redemption, a shareholder must
have completed and returned an account application containing a telephone
election. To add a telephone option to an existing account that previously did
not provide for this option, a Telephone Authorization Form must be filed with
PFPC. This form is available from PFPC. Once this election has been made, the
shareholder may simply contact PFPC by telephone to request the exchange or
redemption by calling (888) 261-4073. Neither RBB, the Fund, the Distributor,
the Administrator nor any other Fund agent will be liable for any loss,
liability, cost or expense for following RBB's telephone transaction procedures
described below or for following instructions communicated by telephone that
they reasonably believe to be genuine.

<PAGE>

to complete a telephone transaction form, listing all of the above caller
identification information; (4) permitting exchanges only if the two account
registrations are identical; (5) requiring that redemption proceeds be sent only
by check to the account owners of record at the address of record, or by wire
only to the owners of record at the bank account of record; (6) sending a
written confirmation for each telephone transaction to the owners of record at
the address of record within five (5) Business Days of the call; and (7)
maintaining tapes of telephone transactions for six months, if the Fund elects
to record shareholder telephone transactions. For accounts held of record by
broker-dealers (other than the Distributor), financial institutions, securities
dealers, financial planners and other industry professionals, additional
documentation or information regarding the scope of a caller's authority is
required. Finally, for telephone transactions in accounts held jointly,
additional information regarding other account holders is required. Telephone
transactions will not be permitted in connection with IRA or other retirement
plan accounts or by an attorney-in-fact under a power of attorney.

NET ASSET VALUE
- --------------------------------------------------------------------------------
The net asset values for each class of a fund are calculated by adding the
value of the proportionate interest of the class in a fund's cash, securities
and other assets, deducting actual and accrued liabilities of the class and
dividing the result by the number of outstanding shares of the class. The net
asset value of each class are calculated independently of each other class. The
net asset values are calculated as of the close of regular trading on the NYSE,
generally 4:00 p.m. Eastern Time on each Business Day.

Valuation of securities held by the Fund is as follows: securities traded
on a national securities exchange or on the NASDAQ National Market System are
valued at the last reported sale price that day; securities traded on a national
securities exchange or on the NASDAQ National Market System for which there were
no sales on that day and securities traded on other over-the-counter markets for
which market quotations are readily available are valued at the mean of the bid
and asked prices; and securities for which market quotations are not readily
available are valued at fair market value as determined in good faith by or
under the direction of the RBB's Board of Directors. The amortized cost method
of valuation may also be used with respect to debt obligations with sixty days
or less remaining to maturity.

With the approval of RBB's Board of Directors, the Fund may use a pricing
service, bank or broker-dealer experienced in such matters to value the Fund's
securities. A more detailed discussion of net asset value and security valuation
is contained in the Statement of Additional Information.

DIVIDENDS AND DISTRIBUTIONS
- --------------------------------------------------------------------------------
The Fund will distribute substantially all of the net investment income and
net realized capital gains, if any, of the Fund to the Fund's shareholders. All
distributions are reinvested in the form of additional full and fractional
Shares unless a shareholder elects otherwise.

The Fund will declare and pay dividends from net investment income annually
and will pay them in the calendar year in which they are declared, generally in
December. Net realized capital gains (including net short-term capital gains),
if any, will be distributed at least annually.

TAXES
- --------------------------------------------------------------------------------
The following discussion is only a brief summary of some of the important
tax considerations generally affecting the Fund and its shareholders and is not
intended as a substitute for careful tax planning. Accordingly, investors in the
Fund should consult their tax advisers with specific reference to their own tax
situation.

<PAGE>

The Fund will elect to be taxed as a regulated investment company under
Subchapter M of the Internal Revenue Code of 1986, as amended. So long as the
Fund qualifies for this tax treatment, it will be relieved of federal income tax
on amounts distributed to shareholders, but shareholders, unless otherwise
exempt, will pay income or capital gains taxes on amounts so distributed (except
distributions that are treated as a return of capital) regardless of whether
such distributions are paid in cash or reinvested in additional shares.

Distributions out of the "net capital gain" (the excess of net long-term
capital gain over net short-term capital loss), if any, of the Fund will be
taxed to shareholders as long-term capital gain regardless of the length of time
a shareholder has held his Shares, whether such gain was reflected in the price
paid for the Shares, or whether such gain was attributable to bonds bearing
tax-exempt interest. All other distributions, to the extent they are taxable,
are taxed to shareholders as ordinary income.

RBB will send written notices to shareholders annually regarding the tax
status of distributions made by the Fund. Dividends declared in December of any
year payable to shareholders of record on a specified date in such a month will
be deemed to have been received by the shareholders on December 31, provided
such dividends are paid during January of the following year. The Fund intends
to make sufficient actual or deemed distributions prior to the end of each
calendar year to avoid liability for federal excise tax.

Investors should be careful to consider the tax implications of buying
shares just prior to a distribution. The price of shares purchased at that time
will reflect the amount of the forthcoming distribution. Those investors
purchasing shares just prior to a distribution will nevertheless be taxed on the
entire amount of the distribution received, although the distribution is, in
effect, a return of capital.

Shareholders who exchange shares representing interests in one Fund for
shares representing interests in another Fund will generally recognize capital
gain or loss for federal income tax purposes.

Shareholders who are nonresident alien individuals, foreign trusts or
estates, foreign corporations or foreign partnerships may be subject to
different U.S. Federal income tax treatment and should consult their tax
advisers.

MULTI-CLASS STRUCTURE
- --------------------------------------------------------------------------------
The Fund offers one other class of shares, Investor Shares, which are
offered directly to individual investors pursuant to a separate prospectus.
Shares of each class represent equal pro rata interests in the Fund and accrue
dividends and calculate net asset value and performance quotations in the same
manner. The Fund will quote performance of the Investor Shares separately from
Institutional Shares. Because of different expenses paid by the Institutional
Shares, the total return on such shares can be expected, at any time, to be
different than the total return on Investor Shares. Information concerning other
classes may be obtained by calling the Fund at (800) 311-9783 or 9829.

DESCRIPTION OF SHARES
- --------------------------------------------------------------------------------
RBB has authorized capital of thirty billion shares of Common Stock, $.001
par value per share, of which 14.928 billion shares are currently classified
into 92 different classes of Common Stock. See "Description of Shares" in the
Statement of Additional Information."

THIS PROSPECTUS AND THE STATEMENT OF ADDITIONAL INFORMATION INCORPORATED
HEREIN RELATE PRIMARILY TO BOSTON PARTNERS MICRO CAP VALUE FUND AND DESCRIBE
ONLY THE INVESTMENT OBJECTIVE AND POLICIES, OPERATIONS, CONTRACTS AND OTHER
MATTERS RELATING TO BOSTON PARTNERS MICRO CAP VALUE FUND.

<PAGE>

Each share that represents an interest in the Fund has an equal
proportionate interest in the assets belonging to the Fund with each other share
that represents an interest in the Fund, even where a share has a different
class designation than another share representing an interest in the Fund.
Shares of the Fund do not have preemptive or conversion rights. When issued for
payment as described in this Prospectus, Shares will be fully paid and
non-assessable.

RBB currently does not intend to hold annual meetings of shareholders
except as required by the 1940 Act or other applicable law. The law under
certain circumstances provides shareholders with the right to call for a meeting
of shareholders to consider the removal of one or more directors. To the extent
required by law, RBB will assist in shareholder communication in such matters.

Holders of Shares of the Fund will vote in the aggregate and not by class
on all matters, except where otherwise required by law. Further, shareholders of
all investment portfolios of RBB will vote in the aggregate and not by portfolio
except as otherwise required by law or when the Board of Directors determines
that the matter to be voted upon affects only the interests of the shareholders
of a particular investment portfolio. (See the Statement of Additional
Information under "Additional Information Concerning Fund Shares" for examples
when the 1940 Act requires voting by investment portfolio or by class.)
Shareholders of the Fund are entitled to one vote for each full share held
(irrespective of class or portfolio) and fractional votes for fractional shares
held. Voting rights are not cumulative and, accordingly, the holders of more
than 50% of the aggregate shares of Common Stock of the Fund may elect all of
the directors.

As of June 15, 1998, to the Fund's knowledge, no person held of record or
beneficially 25% or more of the outstanding shares of all classes of RBB.

OTHER INFORMATION
- --------------------------------------------------------------------------------
REPORTS AND INQUIRIES

Shareholders will receive unaudited semi-annual reports describing the
Fund's investment operations and annual financial statements audited by
independent accountants. Shareholder inquiries should be addressed to PFPC Inc.,
the Fund's transfer agent, Bellevue Park Corporate Center, 400 Bellevue Parkway,
Wilmington, Delaware 19809, toll-free (888) 261-4073.

SHARE CERTIFICATES

In the interest of economy and convenience, physical certificates
representing Shares in the Fund are not normally issued.

FUTURE PERFORMANCE INFORMATION

<PAGE>

Investment Technologies, Inc. or Weisenberger Investment Company Service, or
with the performance of the Russell 2000 Index. Performance information may also
include evaluation of the Fund by nationally recognized ranking services and
information as reported in financial publications such as BUSINESS WEEK,
FORTUNE, INSTITUTIONAL INVESTOR, MONEY MAGAZINE, FORBES, BARRON'S, THE WALL
STREET JOURNAL, THE NEW YORK TIMES, or other national, regional or local
publications. All advertisements containing performance data will include a
legend disclosing that such performance data represents past performance and
that the investment return and principal value of an investment will fluctuate
so that an investor's Shares, when redeemed, may be worth more or less than
their original cost.

<PAGE>

NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR MAKE ANY
REPRESENTATIONS NOT CONTAINED IN THIS PROSPECTUS OR IN RBB'S STATEMENT OF
ADDITIONAL INFORMATION INCORPORATED HEREIN BY REFERENCE, IN CONNECTION WITH THE
OFFERING MADE BY THIS PROSPECTUS AND, IF GIVEN OR MADE, SUCH REPRESENTATIONS
MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED BY RBB OR ITS DISTRIBUTOR.
THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFERING BY RBB OR BY THE DISTRIBUTOR IN
ANY JURISDICTION IN WHICH SUCH OFFERING MAY NOT LAWFULLY BE MADE.

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

TABLE OF CONTENTS

PAGE
----
EXPENSE TABLE ................................ 2
INTRODUCTION ................................. 3
INVESTMENT OBJECTIVES AND POLICIES ........... 3
INVESTMENT LIMITATIONS ....................... 5
RISK FACTORS ................................. 5
MANAGEMENT ................................... 6
HOW TO PURCHASE SHARES ....................... 7
HOW TO REDEEM AND EXCHANGE SHARES ............ 8
NET ASSET VALUE .............................. 11
DIVIDENDS AND DISTRIBUTIONS .................. 11
TAXES ........................................ 11
MULTI-CLASS STRUCTURE ........................ 12
DESCRIPTION OF SHARES ........................ 12
OTHER INFORMATION ............................ 13

INVESTMENT ADVISER
Boston Partners Asset Management, L.P.
Boston, Massachusetts

CUSTODIAN
PNC Bank, N.A.
Philadelphia, Pennsylvania

TRANSFER AGENT AND ADMINISTRATOR
PFPC Inc.
Wilmington, Delaware

DISTRIBUTOR
Provident Distributors, Inc.
West Conshohocken, Pennsylvania

COUNSEL
Drinker Biddle & Reath LLP
Philadelphia, Pennsylvania

INDEPENDENT ACCOUNTANTS
Coopers & Lybrand L.L.P.
Philadelphia, Pennsylvania

<PAGE>

PROSPECTUS
JULY 1, 1998

BOSTON PARTNERS
MICRO CAP
VALUE FUND
(INVESTOR SHARES)

[LOGO OMITTED]

bp
BOSTON PARTNERS ASSET MANAGEMENT, L.P.

<PAGE>

BOSTON PARTNERS MICRO CAP VALUE FUND
(INVESTOR SHARES)
OF
THE RBB FUND, INC.

Boston Partners Micro Cap Value Fund (the "Fund") is an investment
portfolio of The RBB Fund, Inc. ("RBB"), an open-end management investment
company. The shares of the Investor Class ("Shares") offered by this Prospectus
represent interests in the Fund. The Fund is a diversified fund that seeks
long-term growth of capital, with current income as a secondary objective,
primarily through equity investments, such as common stocks. It seeks to achieve
its objectives by investing at least 65% of its total assets in a diversified
portfolio consisting of equity securities of issuers with market capitalizations
that do not exceed $500 million when purchased by the Fund, and identified by
Boston Partners Asset Management, L.P. (the "Adviser") as equity securities that
possess value characteristics. The Adviser examines various factors in
determining the value characteristics of such issuers, including, but not
limited to, price to book value ratios and price to earnings ratios. These value
characteristics are examined in the context of the issuer's operating and
financial fundamentals such as return on equity, earnings growth and cash flow.

PROSPECTUS July 1, 1998

<PAGE>

EXPENSE TABLE
- --------------------------------------------------------------------------------
The following table illustrates the shareholder transaction and annual
operating expenses that are expected to be incurred by Investor Shares of the
Fund (after fee waivers and expense reimbursements) during the next twelve
months as a percentage of average daily net assets. An example based on the
summary is also shown.

SHAREHOLDER TRANSACTION EXPENSES

Maximum Sales Charge Imposed on Purchases ......................... None

Maximum Sales Charge Imposed on Reinvested Dividends .............. None

Maximum Deferred Sales Charge ..................................... None

Redemption Fee(1) ................................................. 1.00%

Exchange Fee ...................................................... None

ANNUAL FUND OPERATING EXPENSES (AS A PERCENTAGE OF AVERAGE NET ASSETS)

Management Fees (after waivers)(2) ................................ 0.00%

12b-1 Fees (after waivers)(2) ..................................... 0.00%

Other Expenses (after expense reimbursements)(2) .................. 1.80%
-----
Total Fund Operating Expenses (after waivers and
expense reimbursements)(2) ................................... 1.80%
=====

(2) In the absence of fee waivers and expense reimbursements, Management Fees
would be 1.25%, Other Expenses would be 2.00%, 12b-1 Fees would be 0.25%
and Total Fund Operating Expenses would be 3.50%. Management Fees and 12b-1
Fees are each based on average daily net assets and are calculated daily
and paid monthly.

EXAMPLE

The Fee Table is designed to assist an investor in understanding the
various costs and expenses that an investor in the Fund will bear directly or
indirectly. (For more complete descriptions of the various costs and expenses,
see "Management" and "Distribution of Shares" below.) The Fee Table reflects
expense reimbursements and voluntary waivers of Management Fees and 12b-1 fees
for the Fund, which are expected to be in effect during the current fiscal year.
However, the Adviser, the Distributor and the Fund's other service providers are
under no obligation with respect

<PAGE>

to such expense reimbursements and waivers and there can be no assurance that
any future expense reimbursements and waivers of Management Fees or 12b-1 Fees
will not vary from the figures reflected in the Fee Table.

<PAGE>

The securities in which the Fund invests will often be traded only in the
over-the-counter market or on a regional securities exchange, may be listed only
in the quotation service commonly known as the "pink sheets," and may not be
traded every day or in the volume typical of trading on a national securities
exchange. They may be subject to wide fluctuations in market value. The trading
market for any given security may be sufficiently thin as to make it difficult
for the Fund to dispose of a substantial block of such securities. The
disposition by the Fund of portfolio securities to meet redemptions or otherwise
may require the Fund to sell these securities at a discount from market prices
or during periods when, in the Adviser's judgment, such disposition is not
desirable or to make many small sales over a lengthy period of time.

<PAGE>

INVESTMENT LIMITATIONS
- --------------------------------------------------------------------------------
The Fund may not change the following investment limitations without
shareholder approval. (A complete list of the investment limitations that cannot
be changed without such a vote of the shareholders is contained in the Statement
of Additional Information under "Investment Objectives and Policies.")

The Fund may not:

PORTFOLIO TURNOVER

<PAGE>

MANAGEMENT
- --------------------------------------------------------------------------------
BOARD OF DIRECTORS

The business and affairs of RBB and the Fund are managed under the
direction of RBB's Board of Directors.

INVESTMENT ADVISER

PORTFOLIO MANAGEMENT

The day-to-day portfolio management of the Fund is the responsibility of
David M. Dabora and Wayne J. Archambo who are portfolio managers of the Adviser.
Prior to taking on day to day responsibilities for the Micro Cap Value Fund, Mr.
Dabora was an assistant portfolio manager/analyst of the premium equity product
of the Adviser, an all-cap value institutional product. Before joining the
Adviser in April 1995, Mr. Dabora had been employed by The Boston Company Asset
Management, Inc. since 1991 as a senior equity analyst. Mr. Dabora has over 10
years of investment experience and is a Chartered Financial Analyst. Mr.
Archambo oversees the investment activities of the Adviser's $900 million of
mid-capitalization value equity product (including the $56 million Mid Cap Value
Fund) and the $1.2 billion small capitalization value institutional equity
product. Prior to joining the Adviser in April 1995, Mr. Archambo had been
employed by The Boston Company Asset Management, Inc. since 1989 as a senior
portfolio manager and a member of that firm's Equity Policy Committee. Mr.
Archambo has over 15 years of investment experience and is a Chartered Financial
Analyst.

ADMINISTRATOR

DISTRIBUTOR

<PAGE>

TRANSFER AGENT, DIVIDEND DISBURSING AGENT, AND CUSTODIAN

PNC Bank, National Association ("PNC Bank") serves as the Fund's custodian
and PFPC serves as the Fund's transfer agent and dividend disbursing agent. The
principal offices of PFPC, an indirect, wholly-owned subsidiary of PNC Bank, are
located at 400 Bellevue Parkway, Wilmington, Delaware 19809. PFPC may enter into
shareholder servicing agreements with registered broker-dealers who have entered
into dealer agreements, with the Distributor ("Authorized Dealers") for the
provision of certain shareholder support services to customers of such
Authorized Dealers who are shareholders of the Fund. The services provided and
the fees payable by the Fund for these services are described in the Statement
of Additional Information under "Investment Advisory, Distribution and Servicing
Arrangements."

EXPENSES

The expenses of the Fund are deducted from its total income before
dividends are paid. Any general expenses of RBB that are not readily
identifiable as belonging to a particular investment portfolio of RBB will be
allocated among all investment portfolios of RBB based upon the relative net
assets of the investment portfolios. The Investor Class of the Fund pays its own
distribution fees, and may pay a different share than the Institutional Class of
other expenses (excluding advisory and custodial fees) if those expenses are
actually incurred in a different amount by the Investor Class or if it receives
different services.

DISTRIBUTION OF SHARES
- --------------------------------------------------------------------------------
The Board of Directors of RBB has approved and adopted a Distribution
Agreement and Plan of Distribution for the Shares (the "Plan") pursuant to Rule
12b-1 under the 1940 Act. Under the Plan, the Distributor is entitled to receive
from the Fund a distribution fee with respect to the Shares, which is accrued
daily and paid monthly, of up to 0.25% on an annualized basis of the average
daily net assets of the Shares. The actual amount of such compensation under the
Plan is agreed upon by RBB's Board of Directors and by the Distributor. The
Distributor may, in its discretion, from time to time waive voluntarily all or
any portion of its distribution fee. The Distributor intends to waive all fees
under the Plan during the current fiscal year.

Amounts paid to the Distributor under the Plan may be used by the
Distributor to cover expenses that are related to (i) the sale of the Shares,
(ii) ongoing servicing and/or maintenance of the accounts of Shareholders, and
(iii) sub-transfer agency services, subaccounting services or administrative
services related to the sale of the Shares, all as set forth in the Fund's 12b-1
Plan. The Distributor may delegate some or all of these functions to Service
Agents. See "How to Purchase Shares - Purchases Through Intermediaries."

The Plan obligates the Fund, during the period it is in effect, to accrue
and pay to the Distributor on behalf of the Shares the fee agreed to under the
Distribution Agreement. Payments under the Plan are not tied exclusively to
expenses actually incurred by the Distributor, and the payments may exceed
distribution expenses actually incurred.

PURCHASES THROUGH INTERMEDIARIES

Shares of the Fund may be available through certain brokerage firms,
financial institutions and other industry professionals (collectively, "Service
Organizations"). Certain features of the Shares, such as the initial and
subsequent investment minimums and certain trading restrictions, may be modified
or waived by Service Organizations. Service Organizations may impose transaction
or administrative charges or other direct fees, which charges and fees would not
be imposed if Shares are purchased directly from the Fund. Therefore, a client
or customer should contact the Service Organization acting on his behalf
concerning the fees (if any) charged in connection with a purchase or redemption
of

<PAGE>

Shares and should read this Prospectus in light of the terms governing his
accounts with the Service Organization. Service Organizations will be
responsible for promptly transmitting client or customer purchase and redemption
orders to the Fund in accordance with their agreements with the Fund and with
clients or customers. Service Organizations or, if applicable, their designees
that have entered into agreements with the Fund or its agent may enter confirmed
purchase orders on behalf of clients and customers, with payment to follow no
later than the Fund's pricing on the following Business Day. If payment is not
received by such time, the Service Organization could be held liable for
resulting fees or losses. The Fund will be deemed to have received a purchase or
redemption order when a Service Organization, or, if applicable, its authorized
designee, accepts a purchase or redemption order in good order. Orders received
by the Fund in good order will be priced at the Fund's net asset value next
computed after they are accepted by the Service Organization or its authorized
designee.

For administration, subaccounting, transfer agency and/or other services,
Boston Partners, the Distributor or their affiliates may pay Service
Organizations and certain recordkeeping organizations a fee of up to .35% (the
"Service Fee") of the average annual value of accounts with the Fund maintained
by such Service Organizations or recordkeepers. The Service Fee payable to any
one Service Organization is determined based upon a number of factors, including
the nature and quality of services provided, the operations processing
requirements of the relationship and the standardized fee schedule of the
Service Organization or recordkeeper.

The Adviser, the Distributor or either of their affiliates may, at their
own expense, provide promotional incentives for qualified recipients who support
the sale of Shares, consisting of securities dealers who have sold Shares or
others, including banks and other financial institutions, under special
arrangements. Incentives may include opportunities to attend business meetings,
conferences, sales or training programs for recipients, employees or clients and
other programs or events and may also include opportunities to participate in
advertising or sales campaigns and/or shareholder services and programs
regarding one or more Boston Partners Funds. Travel, meals and lodging may also
be paid in connection with these promotional activities. In some instances,
these incentives may be offered only to certain institutions whose
representatives provide services in connection with the sale or expected sale of
significant amounts of Shares.

HOW TO PURCHASE SHARES
- --------------------------------------------------------------------------------
GENERAL

Shares representing interests in the Fund are offered continuously for sale
by the Distributor and may be purchased without imposition of a sales charge.
Shares may be purchased initially by completing the application included in this
Prospectus and forwarding the application to the Fund's transfer agent, PFPC.
Purchases of Shares may be effected by wire to an account to be specified by
PFPC or by mailing a check or Federal Reserve Draft, payable to the order of
"The Boston Partners Micro Cap Value Fund," c/o PFPC Inc., P.O. Box 8852,
Wilmington, Delaware 19899-8852. The name of the Fund, Boston Partners Micro Cap
Value Fund, must also appear on the check or Federal Reserve Draft. Shareholders
may not purchase shares of the Boston Partners Micro Cap Value Fund with a check
issued by a third party and endorsed over to the Fund. Federal Reserve Drafts
are available at national banks or any state bank which is a member of the
Federal Reserve System. Initial investments in the Fund must be at least $2,500
and subsequent investments must be at least $100. The Fund reserves the right to
suspend the offering of Shares for a period of time or to reject any purchase
order. As of the date of this Prospectus, the Fund intends to suspend the
offering of Shares upon the Fund's attaining $300 million in total assets.

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BOSTON PARTNERS MICRO CAP VALUE FUND bp
(INVESTOR CLASS) BOSTON PARTNERS ASSET MANAGEMENT, L.P.