RBB FUND INC, 485APOS, 1998-08-25

RBB FUND INC
485APOS, 1998-08-25

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As filed with the Securities and Exchange Commission on August 25, 1998
Securities Act File No. 33-20827
Investment Company Act File No. 811-5518
===============================================================================
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 |X|
Pre-Effective Amendment No. __ |_|
Post-Effective Amendment No. 58 |X|

and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 |X|

Amendment No. 60 |X|

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

THE RBB FUND, INC.

(Government Securities Portfolio: RBB Family Class; BEA
International Equity Portfolio: BEA Class, BEA Investor Class and BEA Advisor
Class; BEA High Yield Portfolio: BEA Class, BEA Investor Class and BEA Advisor
Class; BEA Emerging Markets Equity Portfolio: BEA Class, BEA Investor Class
and BEA Advisor Class; BEA U.S. Core Equity Portfolio: BEA Class and BEA
Advisor Class; BEA U.S. Core Fixed Income Portfolio: BEA Class and Advisor
Class; BEA Strategic Global Fixed Income Portfolio: BEA Class; BEA Municipal
Bond Fund Portfolio: BEA Class; BEA Balanced Fund Portfolio: BEA Class; BEA
Short Duration Portfolio: BEA Class; BEA Global Telecommunications Portfolio:
BEA Investor Class and BEA Advisor Class; BEA Long-Short Market Neutral Fund:
BEA Class and BEA Advisor Class; BEA Long-Short Equity Fund: BEA Class and
BEA Advisor Class; BEA Select Economic Value Equity Fund: BEA Class and BEA
Advisor Class; NI Micro Cap Fund: NI Class; NI Growth Fund: NI Class; NI
Growth & Value Fund: NI Class; NI Larger Cap Value Fund: NI Class; Boston
Partners Large Cap Value Fund: Boston Partners Advisor Class, Boston
Partners Institutional Class and Boston Partners Investor Class; Boston
Partners Mid Cap Value Fund: Boston Partners Institutional Class and Boston
Partners Investor Class; Boston Partners Bond Fund: Boston Partners
Institutional Class and Boston Partners Investor Class; Boston Partners Micro
Cap Value Fund: Boston Partners Institutional Class and Boston Partners
Investor Class; Boston Partners Market Neutral Fund: Boston Partners
Institutional Class and Boston Partners Investor Class; Boston Partners
Long-Short Equity Fund: Boston Partners Institutional Class and Boston
Partners Investor Class; Schneider Small Cap Value Fund; Money Market
Portfolio: RBB Family Class, Cash Preservation Class, Sansom Street Class,
Bedford Class, Janney Class, Beta Class, Gamma Class, Delta Class, Epsilon
Class, Zeta Class, Eta Class and Theta Class; Municipal Money Market Portfolio:
RBB Family Class, Cash Preservation Class, Sansom Street Class, Bedford Class,
Bradford Class, Janney Class, Beta Class, Gamma Class, Delta Class, Epsilon
Class, Zeta Class, Eta Class and Theta Class; Government Obligations Money
Market Portfolio: Sansom Street Class, Bedford Class, Bradford Class, Janney
Class, Beta Class, Gamma Class, Delta Class, Epsilon Class, Zeta Class, Eta
Class and Theta Class; New York Municipal Money Market Portfolio: Bedford
Class, Janney Class, Beta Class, Gamma Class, Delta Class, Epsilon Class,
Zeta Class, Eta Class and Theta Class)

----------------------------------------------------------------
(Exact Name of Registrant as Specified in Charter)
Bellevue Park Corporate Center
400 Bellevue Parkway, Suite 100
Wilmington, DE 19809
(Address of Principal Executive Offices)

Registrant's Telephone Number: (302) 792-2555

<PAGE>

Copies to:
GARY M. GARDNER, ESQUIRE MICHAEL P. MALLOY, ESQUIRE
PNC Bank, National Association Drinker Biddle & Reath LLP
1600 Market Street, 28th Floor 1100 PNB Building
Philadelphia, PA 19103 1345 Chestnut Street
(Name and Address of Agent for Service) Philadelphia, PA 19107-3496

It is proposed that this filing will become effective (check
appropriate box)\
|_| immediately upon filing pursuant to paragraph (b)
|_| on (date) pursuant to paragraph (b)
|_| 60 days after filing pursuant to paragraph (a)(1)
|_| on (date) pursuant to paragraph (a)(1)
|X| 75 days after filing pursuant to paragraph (a)(2)
|_| on (date) pursuant to paragraph (a)(2) of Rule 485
If appropriate, check the following box:
|_| This post-effective amendment designates a new effective date for a
previously filed post-effective amendment.

Title of Securities Being Registered:
Class III, Class JJJ, Class KKK and Class LLL

The purpose of this Post-Effective Amendment is to register two new
portfolios of Registrant and their shares.

<PAGE>

THE RBB FUND, INC.

BOSTON PARTNERS MARKET NEUTRAL FUND
BOSTON PARTNERS LONG-SHORT EQUITY FUND
(INSTITUTIONAL SHARES)

CROSS REFERENCE SHEET
---------------------

<TABLE>
<CAPTION>
FORM N-1A ITEM LOCATION
- -------------- --------

Part A Prospectus

<S> <C> <C>
1. Cover Page............................................... Cover Page

2. Synopsis................................................. Annual Fund Operating Expenses

3. Condensed Financial Information.......................... Expense Table

4. General Description of Registrant........................ Cover Page; Investment Objectives and Policies;
Investment Limitations; Risk Factors; Additional
Investment Policies

5. Management of the Fund................................... Management

6. Capital Stock and Other Securities....................... Cover Page; Dividends and Distributions;
Multi-Class Structure; Description of Shares

7. Purchase of Securities Being Offered..................... How to Purchase Shares; Net Asset Value

8. Redemption or Repurchase................................. How to Redeem and Exchange Shares; Net Asset Value

9. Legal Proceedings........................................ Not applicable
</TABLE>

<PAGE>

BOSTON PARTNERS MARKET NEUTRAL FUND

BOSTON PARTNERS LONG-SHORT EQUITY FUND

(INSTITUTIONAL SHARES)
OF
THE RBB FUND, INC.

BOSTON PARTNERS MARKET NEUTRAL FUND (the "Market Neutral Fund") and
BOSTON PARTNERS LONG-SHORT EQUITY FUND (the "Long-Short Equity Fund" and,
together with the Market Neutral Fund, the "Funds") are investment portfolios of
The RBB Fund, Inc. ("RBB" or the "Company"), an open-end management investment
company. The shares of the Institutional Classes ("Shares") offered by this
Prospectus represent interests in the Funds.

The Market Neutral Fund is a diversified fund that seeks long-term
capital appreciation while minimizing exposure to general equity market risk.
The Market Neutral Fund seeks a total return greater than the total return of
the Salomon Smith Barney U.S. 1-Month Treasury Bill Index(TM). The Market
Neutral Fund pursues its objective by taking long positions in stocks identified
by Boston Partners Asset Management, L.P. (the "Adviser") as undervalued and
short positions in such stocks that the Adviser has identified as overvalued.
Generally, the Market Neutral Fund's investments will be concentrated in
securities principally traded in the United States markets.

The Long-Short Equity Fund is a diversified fund that seeks long-term
capital appreciation while minimizing exposure to general equity market risk.
The Long-Short Equity Fund seeks a total return greater than the total return of
the Standard & Poor's 500 Composite Stock Price Index. The Long-Short Equity
Fund pursues its objective by investing a substantial proportion of its net
assets in shares of the Market Neutral Fund. The Long-Short Equity Fund may also
invest in individual equity securities, futures contracts and other investments.

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 __________, 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 RBB by calling (800) 311-9783
or 9829. 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 FUNDS 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 FUNDS INVOLVE INVESTMENT
RISKS, INCLUDING THE POSSIBLE LOSS OF PRINCIPAL.

<PAGE>

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 __________, 1998

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<PAGE>

EXPENSE TABLE

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

SHAREHOLDER TRANSACTION EXPENSES

MARKET LONG-SHORT
NEUTRAL FUND EQUITY FUND

Maximum Sales Charge Imposed on Purchases............. None None
Maximum Sales Charge Imposed on Reinvested Dividends.. None None
Maximum Deferred Sales Charge......................... None None
Redemption Fee1....................................... 1.00% 1.00%
Exchange Fee.......................................... None None

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

Management Fees (after waivers)2.......................... 1.85% 0.00%
12b-1 Fees............................................... None None
Other Expenses (after waivers and expense reimbursements). 0.65% 2.60%
Total Fund Operating Expenses (after waivers and
expense reimbursements)2......................... 2.50% 2.60%

1 To prevent the Funds from being adversely affected by the transaction
costs associated with short-term shareholder transactions, the Funds
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 the 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 each respective Fund for
the benefit of all shareholders.

2 In the absence of fee waivers and expense reimbursements, Management
Fees would be 2.25% and 0.10%, Other Expenses would be 0.78% and 3.15%,
and Total Fund Operating Expenses would be 3.03% and 3.25% with respect
to the Market Neutral and Long-Short Equity Funds, respectively.
Management Fees are each based on average daily net assets and are
calculated daily and paid monthly.

3 With respect to the Boston Partners Long-Short Equity Fund, "Other
Expenses" includes the indirect expenses associated with the Fund's
investment in Institutional Shares of the Boston Partners Market
Neutral Fund.

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<PAGE>

EXAMPLE

An investor would pay the following expenses on a $1,000 investment in
the Funds, 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 Market Neutral Fund $25 $78
Boston Partners Long-Short Equity Fund $26 $81

The Fee Table is designed to assist an investor in understanding the
various costs and expenses that an investor in the Funds 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 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.

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.

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<PAGE>

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-eight separate investment portfolios. The Shares offered by this
Prospectus represent interests in the Boston Partners Market Neutral and the
Boston Partners Long-Short Equity Fund. RBB was incorporated in Maryland on
February 29, 1988.

INVESTMENT OBJECTIVES AND POLICIES

The MARKET NEUTRAL FUND is a diversified fund that seeks long-term
capital appreciation while minimizing exposure to general equity market risk.
The Market Neutral Fund seeks a total return greater than the total return of
the Salomon Smith Barney U.S. 1-Month Treasury Bill Index(TM). The Market
Neutral Fund pursues its objective by taking long positions in stocks identified
by the Adviser as undervalued and short positions in such stocks that the
Adviser has identified as overvalued. The cash proceeds from short sales will be
invested in short-term cash instruments to produce a return on such proceeds
just below the federal funds rate. Generally, the Market Neutral Fund's
investments will be concentrated in securities principally traded in the United
States markets. See "Risk Factors -- Short Sales" below. By taking long and
short positions in different stocks with similar characteristics, the Fund
attempts to minimize the effect of general stock market movements on the Fund's
performance. The Adviser will determine the size of each long or short position
by analyzing the tradeoff between the attractiveness of each position and its
impact on the risk of the overall portfolio. The Fund seeks to construct a
portfolio that has minimal net exposure to the U.S. equity market generally and
low to neutral exposure to specific industries, specific capitalization ranges
(e.g., large cap, mid cap and small cap) and certain other factors.

Although the Market Neutral Fund's investment strategy seeks to
minimize the risk associated with investing in the equity market, an investment
in the Market Neutral Fund will be subject to the risk of poor stock selection
by the Adviser. In other words, the Adviser may not be successful in executing
its strategy of taking long positions in stocks that outperform the market and
short positions in stocks that underperform the market. Further, since the
Adviser will manage both a long and a short portfolio, an investment in the
Market Neutral Fund will involve the risk that the Adviser may make more poor
investment decisions than an adviser of a typical stock mutual fund with only a
long portfolio may make. An investment in one-month U.S. Treasury Bills is
different from an investment in the Market Neutral Fund because Treasury Bills
are backed by the full faith and credit of the U.S. Government, Treasury Bills
have a fixed rate of return and investors in Treasury Bills do not bear the risk
of losing their investment.

To meet margin requirements, redemptions or pending investments, the
Market Neutral Fund may also temporarily hold a portion of its assets in full
faith and credit obligations of the United States government (e.g., U.S.
Treasury Bills) and in short-term notes, commercial paper or other money market
instruments of high quality (i.e., rated at least "A-2" or "AA" by Standard

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<PAGE>

& Poor's ("S&P") or Prime 2 or "Aa" by Moody's Investors Service, Inc.
("Moody's")) issued by companies having an outstanding debt issue rated at least
"AA" by S&P or at least "Aa" by Moody's, or determined by the Adviser to be of
comparable quality to any of the foregoing.

The Market Neutral Fund's long and short positions may involve (without
limit) equity securities of foreign issuers that are traded in the markets of
the United States as sponsored American Depository Receipts ("ADRs"). ADRs are
receipts typically issued by a U.S. bank or trust company evidencing ownership
of the underlying foreign securities. Generally, ADRs, in registered form, are
designed for use in U.S. securities markets. The ADRs may not necessarily be
denominated in the same currency as the foreign securities underlying the ADRs.
See "Risk Factors -- Foreign Investments." The Market Neutral Fund may also
invest up to 20% of its total assets directly in stocks of foreign issuers.

The investment objective of the LONG-SHORT EQUITY FUND is to seek a
total return greater than that of the Standard & Poor's 500 Composite Stock
Price Index (the "S&P 500 Index"). The Fund seeks to achieve its objective by
investing in Institutional Shares of the Market Neutral Fund while
simultaneously utilizing S&P 500 Index futures, options on S&P 500 Index futures
and equity swap contracts to gain exposure to the equity market as measured by
the S&P 500 Index. See "Investment Objectives and Policies -- Market Neutral
Fund" and "Risk Factors -- S&P 500 Index Futures and Related Options" and "--
Equity Swap Contracts" below. The Long-Short Equity Fund has applied to the SEC
for an exemptive order allowing it to invest without limit in the Market Neutral
Fund. Under normal market conditions, the Long-Short Equity Fund will invest at
least 65% of the value of its total assets in U.S. equity securities (which
include shares of the Market Neutral Fund). Once the Fund has indirectly
acquired a long and short portfolio through the purchase of Institutional Shares
of the Market Neutral Fund, the Adviser will purchase S&P 500 Index futures,
options on S&P 500 Index futures and equity swap contracts in an amount
approximately equal to the net asset value of the Long-Short Equity Fund in
order to gain full net exposure to the U.S. equity market as measured by the S&P
500 Index. In addition to purchasing Institutional Shares of the Market Neutral
Fund, the Long-Short Equity Fund may also take long positions in stocks
principally traded in the markets of the United States that the Adviser has
identified as undervalued and short positions in such stocks that the Adviser
has identified as overvalued. See "Risk Factors -- Short Sales."

The S&P 500 Index is an unmanaged index composed of 500 common stocks,
most of which are listed on the New York Stock Exchange. The S&P 500 Index
assigns relative values to the stocks included in the index, weighted according
to each stock's total market value relative to the total market value of the
other stocks included in such index.

To meet margin requirements, redemptions or pending investments, the
Long-Short Equity Fund may also temporarily hold a portion of its assets in full
faith and credit obligations of the United States government (e.g., U.S.
Treasury Bills) and in short-term notes, commercial paper or other money market
instruments of high quality (i.e., rated at least "A-2" or "AA" by S&P or Prime
2 or "Aa" by Moody's) issued by companies having an outstanding debt issue

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<PAGE>

rated at least "AA" by S&P or at least "Aa" by Moody's, or determined by the
Adviser to be of comparable quality to any of the foregoing.

The Long-Short Equity Fund's long and short positions may involve
(without limit) equity securities of foreign issuers that are traded in the
markets of the United States as ADRs, which are described above under "Market
Neutral Fund." See "Risk Factors -- Foreign Investments." The Fund may also
invest up to 20% of its total assets directly in stocks of foreign issuers.

In a typical stock mutual fund the investment adviser attempts to earn
an excess return (return above market return) or "alpha" by identifying and
purchasing undervalued stocks. However, there is another "alpha" possibility --
identifying and selling short overvalued stocks. The term "double alpha" refers
to these two potential sources of alpha: one from correctly identifying
undervalued stocks and one from correctly identifying overvalued stocks. The
market neutral strategy employed directly by the Market Neutral Fund and
indirectly by the Long-Short Equity Fund (through investment in shares of the
Market Neutral Fund) seeks to capture both alphas. The Long-Short Equity Fund
also seeks to replicate the market (and incurs additional cost and expense risk)
by investing in S&P 500 Index instruments.

While the Adviser intends to fully invest each Fund's assets at all
times in accordance with the above-mentioned policies, each Fund reserves the
right to hold up to 100% of its respective 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.

Each 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 such
Fund.

INVESTMENT LIMITATIONS

The Funds 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.")

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<PAGE>

Neither Fund may borrow money or issue senior securities, except that
each 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 such Fund's total assets at
the time of such borrowing. Neither Fund will 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 Funds' investment
practices are not considered to be borrowings or deemed to be pledged for
purposes of this limitation.

If a percentage restriction under one of the Funds' investment policies
or restrictions or the use of assets is adhered to at the time a transaction is
effected, later changes in percentage resulting from changing values will not be
considered a violation (except with respect to any restrictions that may apply
to borrowings or senior securities issued by the Fund).

RISK FACTORS

SPECIAL RISKS AND OTHER CONSIDERATIONS RELATING TO THE LONG-SHORT
EQUITY FUND. Because the Long-Short Equity Fund may invest up to 100% of its
assets in shares of the Market Neutral Fund and other investment companies, the
expenses associated with investing in the Long-Short Equity Fund may be higher
than those associated with a portfolio that directly invests in securities that
are not themselves investment companies. An investor in the Long-Short Equity
Fund will incur a proportionate share of the expenses of that Fund, as well as a
proportionate share of expenses of the Market Neutral Fund and unaffiliated
investment companies in which the Long-Short Equity Fund invests (collectively,
the "Underlying Funds"). Investors in the Long-Short Equity Fund should realize
that they can invest directly in the Underlying Funds.

The Long-Short Equity Fund will seek to avoid duplicative fees and the
layering of expenses to the extent practicable. The Fund will generally invest
in the Institutional Shares of the Market Neutral Fund, which are offered to the
Fund with no sales or redemption charges or distribution fees; however, the Fund
may invest in shares of other investment companies which may be offered with
sales or redemption charges or distribution fees. The management fees payable to
the Adviser under the Long-Short Equity Fund's advisory contract are for
services that are in addition to, rather than duplicative of, services provided
under the advisory contract for any Underlying Funds in which the Long-Short
Equity Fund invests. The administration, custody and transfer agency fees borne
by the Long-Short Equity Fund are also for services that are in addition to, and
not duplicative of, services provided to the Underlying Funds. In addition, the
distribution fees relating to Investor Shares of the Long-Short Equity Fund,
when aggregated with any distribution or shareholder servicing fees paid by the
Fund in connection with its

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<PAGE>

investments in underlying funds will not exceed applicable NASD limits.

As a fund that may invest a substantial portion of its assets in other
investment companies, the Long-Short Equity Fund will be subject to certain
investment risks. The Fund's performance is directly related to the performance
of the Market Neutral Fund and the other investment companies in which it
invests. Accordingly, the ability of the Long-Short Equity Fund to meet its
investment objective is directly related to the ability of the Underlying Funds
to meet their objectives. There can be no assurance that the investment
objective of any Underlying Fund will be achieved.

From time to time, the Market Neutral Fund may experience relatively
large purchases or redemptions due to asset allocation decisions made by the
Adviser in managing the Long-Short Equity Fund and other client accounts. These
transactions may have a material effect on the Market Neutral Fund. While it is
impossible to predict the overall impact of these transactions over time, there
could be adverse effects on the Market Neutral Fund to the extent that it may be
required to sell securities at times when it would not otherwise do so or
receive cash that cannot be invested in an expeditious manner. There may be tax
consequences associated with purchases and sales of securities, and such sales
may also increase transaction costs. The Adviser is committed to minimizing the
impact of these transactions on the Market Neutral Fund to the extent it is
consistent with pursuing the Long-Short Equity Fund's investment objective and
will monitor the impact of the Long-Short Equity Fund's asset allocation
decisions on the Market Neutral Fund.

INVESTMENT RISKS. The value of Fund shares may increase or decrease
depending on market, economic, political, regulatory and other conditions
affecting each Fund's portfolio. As of the date of this Prospectus, U.S. stock
markets were trading at historically high levels and there can be no guarantee
that such levels will continue. Investment in Shares of the Funds is more
volatile and risky than some other forms of investment. In addition, if the
Adviser takes long positions in stocks that decline or short positions in stocks
that increase in value, then the losses of the Market Neutral Fund and
Long-Short Equity Fund may exceed those of other stock mutual funds that hold
long positions only.

SHORT SALES. When the Adviser anticipates that a security is
overvalued, it may sell the security short by borrowing the same security from a
broker or other institution and selling the security. A Fund will incur a loss
as a result of a short sale if the price of the borrowed security increases
between the date of the short sale and the date on which the Fund replaces such
security. A Fund will realize a gain if there is a decline in price of the
security between those dates, which decline exceeds the costs of the borrowing
the security and other transaction costs. There can be no assurance that a Fund
will be able to close out a short position at any particular time or at an
acceptable price. Although a Fund's gain is limited to the amount at which it
sold a security short, its potential loss is unlimited since it is directly
tied to the maximum attainable price of the security less the price at which the
security was sold. Until a Fund replaces a borrowed security, it will maintain
at all times cash, U.S. Government securities, or other liquid securities in an
amount

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<PAGE>

which, when added to any amount deposited with a broker as collateral
will at least equal the current market value of the security sold short.
Depending on arrangements made with brokers, a Fund may not receive any payments
(including interest) on collateral deposited with them. The Funds will not make
a short sale if, after giving effect to such sale, the market value of all
securities sold short exceeds 100% of the value of a Fund's net assets.

S&P 500 INDEX FUTURES AND RELATED OPTIONS (LONG-SHORT EQUITY FUND
ONLY). An S&P 500 Index Future contract (an "Index Future") is a contract to buy
or sell an integral number of units of the S&P 500 Index at a specified future
date at a price agreed upon when the contract is made. A unit is the value at a
given time of the S&P 500 Index. Entering into a contract to buy units is
commonly referred to as buying or purchasing a contract or holding a long
position in the S&P 500 Index. An option on an Index Future gives the purchaser
the right, in return for the premium paid, to assume a long or a short position
in an Index Future. The Long-Short Equity Fund will realize a loss if the value
of the S&P 500 Index declines between the time the Fund purchases an Index
Future or an option transaction in which the Fund has assumed a long position
and may realize a gain if the value of the S&P 500 Index rises between such
dates.

The Long-Short Equity Fund may close out a futures contract purchase by
entering into a futures contract sale. This sale will terminate the Fund's
position in the futures contract. Positions in Index Futures may be closed out
by the Fund only on the futures exchanges on which the Index Futures are then
traded. There can be no assurance that a liquid market will exist for any
particular contract at any particular time. The liquidity of the market in
futures contracts could be adversely affected by "daily price fluctuation
limits" established by the relevant futures exchange which limit the amount of
fluctuation in the price of an Index Future during a single trading day. Once
the daily limit has been reached in the contract, no trades may be entered into
at a price beyond the limit. In such event, it may not be possible for the Fund
to close its futures contract purchase, and, in the event of adverse price
movements, the Fund would continue to be required to make daily cash payments of
variation margin (payments to and from a broker made on a daily basis as the
price of the Index Future fluctuates). The futures market may also attract more
speculators than does the securities market, because deposit requirements in the
futures market are less onerous than margin requirements in the securities
market. Increased participation by speculators in the futures market may also
cause price distortions.

Further, when the Long-Short Equity Fund purchases an Index Future, it
is required to maintain, at all times while an Index Future is held by the Fund,
cash, U.S. Government securities or other liquid securities in an amount which,
together with the initial margin deposit on the futures contract, is equal to
the current value of the futures contract.

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counterparty a floating rate of interest (typically the London Inter Bank
Offered Rate) on the notional amount of the equity swap contract plus the
amount, if any, by which that notional amount would have decreased in value
had it been invested in such stocks. Therefore, the return to the Fund on any
equity swap contract should be the gain or loss on the notional amount plus
dividends on the stocks comprising the S&P 500 Index (as if the Fund had
invested the notional amount in stocks comprising the S&P 500 Index) less the
interest paid by the Fund on the notional amount. Therefore, the Fund will
generally realize a loss if the value of the S&P 500 Index declines and will
generally realize a gain if the value of the S&P 500 Index rises. The Fund will
enter into equity swap contracts only on a net basis, I.E., where the two
parties' obligations are netted out, with the Fund paying or receiving, as the
case may be, only the net amount of any payments. If there is a default by the
counterparty to an equity swap contract, the Fund will be limited to
contractual remedies pursuant to the agreements related to the transaction.

There is no assurance that the equity swap contract counterparties will
be able to meet their obligations or that, in the event of default, the
Long-Short Equity Fund will succeed in pursuing contractual remedies. The Fund
thus assumes the risk that it may be delayed in or prevented from obtaining
payments owed to it pursuant to these contracts. The Adviser will closely
monitor the credit of equity swap contract counterparties to seek to minimize
this risk. The Long-Short Equity Fund will not use equity swap contracts for
leverage.

The Long-Short Equity Fund will not enter into any equity swap contract
unless, at the time of entering into such transaction, the unsecured senior debt
of the counterparty is rated at least A by Moody's or S&P. In addition, the
staff of the Securities and Exchange Commission (the "SEC") considers equity
swap contracts to be illiquid securities. Consequently, as long as the staff
maintains this position, the Fund will not invest in equity swap contracts if,
as a result of the investment, the total value of such investments together with
that of all other illiquid securities which the Fund owns would exceed 15% of
the Fund's net assets.

The net amount of the excess, if any, of the Long-Short Equity Fund's
obligations over its entitlement with respect to each equity swap contract will
be accrued on a daily basis, and an amount of cash, U.S. Government Securities
or other liquid securities having an aggregate market value at least equal to
the accrued excess will be maintained in a segregated account. The Fund does not
believe that the Fund's obligations under equity swap contracts are senior
securities within the meaning of the 1940 Act, so long as such a segregated
account is maintained, and accordingly, the Fund will not treat them as being
subject to its borrowing restrictions.

FOREIGN INVESTMENTS. Investing in foreign companies may involve
additional risks and considerations which are not typically associated with
investing in U.S. companies. Since stocks of foreign companies are normally
denominated in foreign currencies, the Funds may be affected favorably or
unfavorably by changes in currency rates and in exchange control regulations,
and may incur costs in connection with conversions between various currencies.

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<PAGE>

As non-U.S. companies are not generally subject to uniform accounting,
auditing and financial reporting standards and practices comparable to those
applicable to U.S. companies, comparable information may not be readily
available about certain foreign companies. Some securities of foreign companies
may be less liquid and more volatile than securities of comparable U.S.
companies. In addition, in certain foreign countries, there is the possibility
of expropriation or confiscatory taxation, political or social instability, or
diplomatic developments which could affect U.S. investments in those countries.

GENERAL. Investment methods described in this Prospectus are among
those which the Funds have the power to utilize. 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.

ADDITIONAL INVESTMENT POLICIES

This section describes certain investment policies that are common to
each Fund. Investment policies are described in more detail in the Statement of
Additional Information.

TEMPORARY INVESTMENTS. For defensive purposes or during temporary
periods in which the Adviser believes changes in economic, financial or
political conditions make it advisable, each Fund may reduce its holdings in
equity and other securities and invest up to 100% of its assets in cash or
certain short-term (less than twelve months to maturity) and medium-term (not
greater than five years to maturity) interest-bearing instruments or deposits of
United States and foreign issuers. Such investments may include, but are not
limited to, commercial paper, certificates of deposit, variable or floating rate
notes, bankers' acceptances, time deposits, government securities and money
market deposit accounts. See Statement of Additional Information, "Common
Investment Policies -- Temporary Investments." To the extent permitted by their
investment objectives and policies, the Funds may hold cash or cash equivalents
pending investment.

BORROWING. A Fund may borrow up to 331/3 percent of its total assets
without obtaining shareholder approval. The Adviser intends to borrow, or to
engage in reverse repurchase agreements, only for temporary or emergency
purposes. See Statement of Additional Information, "Common Investment
Policies -- All Funds -- Reverse Repurchase Agreements" and "-- Borrowing."

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<PAGE>

the securities fail financially. However, loans will be made only to borrowers
deemed by the Adviser to be of good standing and only when, in the Adviser's
judgment, the income to be earned from the loans justifies the attendant risks.
Any loans of a Fund's securities will be fully collateralized and marked to
market daily. A Fund may not make loans in excess of 331/3% of the value of its
total assets (including the loan collateral).

RULE 144A SECURITIES. Rule 144A securities are securities which are
restricted as to resale to the general public, but which may be resold to
qualified institutional buyers. A Fund's investment in Rule 144A securities
could have the effect of increasing the level of illiquidity of the Fund during
any period that qualified institutional buyers were no longer interested in
purchasing these securities. For purposes of each Fund's 15% limitation on
purchase of illiquid securities as described below, Rule 144A securities will
not be considered to be illiquid if the Adviser has determined them to be liquid
pursuant to guidelines established by the Company's Board of Directors.

REPURCHASE AGREEMENTS. Each Fund may enter into repurchase agreements,
by which a Fund purchases a security and obtains a simultaneous commitment from
the seller (a bank or, to the extent permitted by the 1940 Act, a recognized
securities dealer) to repurchase the security at an agreed-upon price and date
(usually seven days or less from the date of original purchase). The resale
price is in excess of the purchase price and reflects an agreed-upon market rate
unrelated to the coupon rate on the purchased security. Such transactions afford
the Funds the opportunity to earn a return on temporarily available cash.
Although the underlying security may be a bill, certificate of indebtedness,
note or bond issued by an agency, authority or instrumentality of the U.S.
Government, the obligation of the seller is not guaranteed by the U.S.
Government and there is a risk that the seller may fail to repurchase the
underlying security. In such event, a Fund would attempt to exercise rights with
respect to the underlying security, including possible disposition in the
market. However, a Fund may be subject to various delays and risks of loss,
including (a) possible declines in the value of the underlying security during
the period while a Fund seeks to enforce its rights thereto and (b) inability to
enforce rights and the expenses involved in attempted enforcement.

ILLIQUID SECURITIES. Each Fund may purchase "illiquid securities",
defined as securities which cannot be sold or disposed of in the ordinary course
of business within seven days at approximately the price at which a Fund has
valued such securities, so long as no more than 15% of a Fund's net assets would
be invested in such illiquid securities after giving effect to a purchase.
Investment in illiquid securities involves the risk that, because of the lack of
consistent market demand for such securities, a Fund may be forced to sell them
at a discount from the last offer price.

INVESTMENT COMPANIES. Each Fund may invest in securities issued by
unaffiliated investment companies to the extent permitted by the 1940 Act. As a
shareholder of another investment company, each Fund would bear, along with
other shareholders, its pro rata portion of the other investment company's
expenses, including management fees. These expenses would be

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in addition to the management fees and other expenses that a Fund bears
directly in connection with its own operations.

The 1940 Act generally permits the Long-Short Equity Fund to invest
without limitation in other investment companies that are part of the same
"group of investment companies" (as defined in the 1940 Act), provided certain
limitations are observed. Generally, these limitations require that the Fund (a)
limit its investments to shares of other investment companies that are part of
the same "group of investment companies," Government securities and short-term
paper; (b) observe certain limitations on the amount of sales loads and
distribution-related fees that are borne directly and indirectly by its
shareholders; and (c) not invest in other investment companies structured as
"funds of funds." An exemptive order issued by the SEC permits the Long-Short
Equity Fund to hold investments other than those identified above, including
domestic and foreign equity and fixed income securities, S&P 500 Index futures
and related options, equity swap contracts and shares of unaffiliated investment
companies.

PORTFOLIO TURNOVER. The Adviser will effect portfolio transactions in
each Fund without regard to holding periods if, in its judgment, such
transactions are advisable in light of general market, economic or financial
conditions. The annual portfolio turnover rate for each of the Market Neutral
Fund and the Long-Short Equity Fund is not expected to exceed 200%. Portfolio
turnover may vary greatly from year to year as well as within a particular year.
High portfolio turnover rates (100% or more) will generally result in higher
transaction costs to a Fund and may result in the realization of short-term
capital gains that are taxable to shareholders as ordinary income. The amount of
portfolio activity will not be a limiting factor when making portfolio
decisions. See the Statement of Additional Information, "Portfolio Transactions"
and "Taxes."

AMERICAN DEPOSITORY RECEIPTS. Each Fund may invest in ADRs. ADRs are
typically issued by a U.S. bank or trust evidencing ownership of the underlying
foreign securities. Generally, ADRs, in registered form, are designed for use in
U.S. securities markets. ADRs may be listed on a national securities exchange or
may be traded in the over-the-counter market. ADRs traded in the
over-the-counter market which do not have an active or substantial secondary
market will be considered illiquid and therefore will be subject to the Funds'
respective limitations with respect to such securities. ADRs may be denominated
in U.S. dollars although the underlying securities may be denominated in a
foreign currency. Investments in ADRs involve risks similar to those
accompanying direct investments in foreign securities. Certain of these risks
are described above under "Foreign Investments."

The Statement of Additional Information contains additional investment
policies and strategies of the Funds.

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<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 28 State Street,
21st Floor, Boston, Massachusetts, 02109 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 June 30, 1998 in excess of
$16.7 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 each Fund's portfolio in accordance with that
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 Funds, the Adviser is paid a monthly advisory fee
computed at an annual rate of 2.25% and 0.10% of the Market Neutral Fund's and
Long-Short Equity Fund's respective average daily net assets. The Adviser has
notified RBB, however, that it intends to waive all advisory fees during the
current fiscal year.

PORTFOLIO MANAGEMENT

The day-to-day portfolio management of each Fund is the responsibility
of Edmund D. Kellogg, subject to the supervision of Harry J. Rosenbluth.
Both Mr. Kellogg and Mr. Rosenbluth are portfolio managers employed by the
Adviser. Previously, Mr. Kellogg was a portfolio manager/analyst for a similar
limited partnership private investment fund and a separate account of the
Adviser. Before joining the Adviser in 1996, Mr. Kellogg was employed by The
Keystone Group since 1991, where he was a portfolio manager and analyst
managing institutional separate accounts. Mr. Kellogg has over 21 years of
investment experience and is a Chartered Financial Analyst. Mr. Rosenbluth
oversees other institutional accounts of the Adviser and manages a $2.2 billion
all-capitalization value equity institutional separate account product. Prior
to joining the Adviser in 1995, Mr. Rosenbluth was employed by The Boston
Company Asset Management since 1981 as a senior portfolio manager. Mr.
Rosenbluth has over 17 years of investment experience and is a Chartered
Financial Analyst.

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<PAGE>

ADMINISTRATOR

PFPC Inc. ("PFPC") serves as administrator to the Funds and generally
assists each 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.

ADMINISTRATIVE SERVICES AGENT

Provident Distributors, Inc. ("PDI"), a wholly-owned subsidiary of PNC
Bank Corp. provides certain administrative services to each Fund's Institutional
Shares not otherwise provided by PFPC. PDI's principal business address is Four
Falls Corporate Center, West Conshohocken, Pennsylvania 19428. PDI furnishes
certain corporate secretarial, data processing and clerical services, acts as a
liaison between the Funds and their various service providers, assists in
coordinating the preparation of reports to shareholders, including proxy
statements and annual, semi-annual and quarterly reports and generally assists
in monitoring and developing compliance procedures for the Fund. For its
services, PDI is entitled to a monthly fee calculated at the annual rate of
.15% of the average daily net assets of each Fund's Institutional Class. PDI
is currently waiving fees in excess of .03% of the average daily net assets of
each Fund's Institutional Class.

TRANSFER AGENT, DIVIDEND DISBURSING AGENT, AND CUSTODIAN

DISTRIBUTOR

PDI acts as distributor for the Shares pursuant to a distribution
agreement (the "Distribution Agreement") with RBB on behalf of the Shares.

EXPENSES

The expenses of each 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 each Fund pays
its own administrative services fees, and may pay a different share of 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.

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<PAGE>

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

HOW TO PURCHASE SHARES

GENERAL

Shares representing an interest in the Funds 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
Funds' 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 Market Neutral Fund" or "The Boston
Partners Long-Short Equity Fund," as appropriate, c/o PFPC Inc., P.O. Box 8852,
Wilmington, Delaware 19899-8852. The name of the Fund, either Boston Partners
Market Neutral Fund or Boston Partners Long-Short Equity Fund, must also appear
on the check or Federal Reserve Draft. Shareholders may not purchase shares of
either the Boston Partners Market Neutral Fund or the Boston Partners Long-Short
Equity Fund with a check issued by a third party and endorsed over to either
such 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, foundations or other related groups may be aggregated. Each
Fund reserves the right to suspend the offering of its Shares for a period of
time or to reject any purchase order.

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.

The price paid for Shares purchased is based on the net asset value
next computed after a purchase order is received in good order by a Fund or its
agents. Orders received by a Fund or its agents prior to the close of the NYSE
(generally 4:00 p.m. Eastern Time) are priced at that Business Day's net asset
value. Orders received by a Fund or its agents after its 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.

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<PAGE>

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, and by any
pension and profit-sharing plan of the Adviser, 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 Funds do not currently impose a service charge for effecting
wire transfers but reserve 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 Funds' 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 Funds' transfer agent to withdraw funds from your bank account.
Investors desiring to participate in the automatic investing program should call
the Funds' transfer agent, PFPC, at (888) 261-4073 to obtain the appropriate
forms.

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<PAGE>

HOW TO REDEEM AND EXCHANGE SHARES

REDEMPTION BY MAIL

Shareholders may redeem for cash some or all of their Shares of a Fund
at any time. To do so, a written request in proper form must be sent directly to
Boston Partners Market Neutral Fund or Boston Partners Long-Short Equity Fund,
as appropriate, 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.

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 Funds' transfer agent in the event redemption is
requested by a corporation, partnership, trust, fiduciary, executor or
administrator.

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<PAGE>

TRANSACTION FEE IMPOSED ON CERTAIN REDEMPTIONS

Each Fund requires the payment of a transaction fee on redemptions of
Shares of such 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 particular 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 a 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 a Fund; and (4) the effect of the
"bid-ask" spread in the over-the-counter market. The 1.00% amount represents the
Funds' estimate of the brokerage and other transaction costs which may be
incurred by a Fund in disposing of stocks in which such Fund may invest. Without
the additional transaction fee, each 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

Each 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. IN SUCH CASES,
NEITHER FUND WILL IMPOSE THE 1% TRANSACTION FEE.

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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 a 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 a 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 Funds'
transfer agent may delay mailing a redemption check, which may be a period of up
to 15 days, pending a determination that the check has cleared. The Funds have
elected to be governed by Rule 18f-1 under the 1940 Act so that a Fund 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.

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 either Fund for Institutional Shares of the other Fund or for
Institutional Shares of the Boston Partners Large Cap Value Fund, Boston
Partners Mid Cap Value Fund, Boston Partners Micro 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 Fund
exchanged for next determined after PFPC's receipt of a request for an exchange.
An exchange of shares held for less than one-year (with the exception of shares
purchased through dividend reinvestment or the reinvestment of capital gains)
will be subject to the 1.00% transaction fee. 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 any other Boston Partners Fund of RBB, 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

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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 an RBB Fund advised by Boston
Partners, 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 Funds' 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 a Fund and increase transactions costs, each Fund has established
a policy of limiting excessive exchange activity.

Shareholders are entitled to six (6) exchange redemptions (at least 30
days apart) from a Fund during any twelve-month period. Notwithstanding these
limitations, each Fund reserves the right to reject any purchase request
(including exchange purchases from an RBB Fund advised by Boston Partners) 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 Funds, 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.

RBB's telephone transaction procedures include the following measures:
(1) requiring the appropriate telephone transaction privilege forms; (2)
requiring the caller to provide the names of the account owners, the account
social security number and name of the Fund, all of which must match RBB's
records; (3) requiring RBB's service representative 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

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transactions for six months, if a 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 value for each class of a Fund is 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 is 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 a 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 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, a Fund may use a pricing
service, bank or broker-dealer experienced in such matters to value such 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

Each 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.

Each Fund will declare and pay dividends from net investment income
annually and will pay them within five (5) days from the last day of the
calendar year. Net realized capital gains (including net short-term capital
gains), if any, will be distributed at least annually.

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TAXES

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

Each Fund will elect to be taxed as a regulated investment company
for federal income tax purposes. So long as each Fund qualifies for this tax
treatment, it will be relieved of federal income tax on amounts distributed to
shareholders. Each Fund intends to make sufficient actual or deemed
distributions prior to the end of each calendar year to avoid liability for
federal income or excise tax.

Fund distributions to shareholders, unless otherwise exempt, will be
taxable (except distributions that are treated for federal income tax purposes
as a return of capital) regardless of whether the distributions are received 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 a Fund, and out of the portion of such net capital gain that
constitutes mid-term capital gain, will be taxed to shareholders as long-term
capital gain, or mid-term capital gain, as the case may be, regardless of the
length of time a shareholder has held his Shares. All other taxable
distributions 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 October,
November or 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, if such dividends are paid during January of
the following year.

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 sell or redeem shares, or 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. The gain or loss will be long-term capital gain or loss if the shares
have been held for more than twelve months, and short-term otherwise, except
that a loss on shares held six months or less will be treated as long-term
capital loss to the extent of any capital gains distribution received on the
shares.

Shareholders who are nonresident alien individuals, foreign trusts or
estates, foreign corporations or foreign partnerships are generally subject to
different U.S. Federal income tax

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<PAGE>

treatment from that described above. In particular, such shareholders will
generally not be subject to U.S. federal income tax on capital gains on or with
respect to their shares, and other distributions to them will be subject to
30% withholding tax unless such tax is reduced or eliminated under an applicable
tax treaty.

MULTI-CLASS STRUCTURE

Each 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 a Fund and accrue
dividends and calculate net asset value and performance quotations in the same
manner. The Funds 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 Funds 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 ___ billion shares are currently classified
into __ 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 MARKET NEUTRAL FUND AND
BOSTON PARTNERS LONG-SHORT EQUITY FUND AND DESCRIBE ONLY THE INVESTMENT
OBJECTIVE AND POLICIES, OPERATIONS, CONTRACTS AND OTHER MATTERS RELATING TO
BOSTON PARTNERS MARKET NEUTRAL FUND OR BOSTON PARTNERS LONG-SHORT EQUITY FUND.

Each share that represents an interest in a Fund has an equal
proportionate interest in the assets belonging to that 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 such
Fund. Shares of a 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.

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<PAGE>

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 a 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 a Fund may elect all of the directors.

As of July 29, 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 each
Fund's investment operations and annual financial statements audited by
independent accountants. Shareholder inquiries should be addressed to PFPC Inc.,
the Funds' 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 Funds are not normally issued.

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<PAGE>

FUTURE PERFORMANCE INFORMATION

From time to time, each Fund may advertise its performance, including
comparisons to other mutual funds with similar investment objectives and to
stock or other relevant indices. All such advertisements will show the average
annual total return over one, five and ten year periods or, if such periods have
not yet elapsed, shorter periods corresponding to the life of such Fund. Such
total return quotations will be computed by finding the compounded average
annual total return for each time period that would equate the assumed initial
investment of $1,000 to the ending redeemable value, net of fees, according to a
required standardized calculation. The standard calculation is required by the
SEC to provide consistency and comparability in investment company advertising.
Each Fund may also from time to time include in such advertising an aggregate
total return figure or a total return figure that is not calculated according to
the standardized formula in order to compare more accurately the Fund's
performance with other measures of investment return. For example, a Fund's
total return may be compared with data published by Lipper Analytical Services,
Inc., CDA Investment Technologies, Inc. or Weisenberger Investment Company
Service, or with the performance of the Salomon Smith Barney U.S. 1-Month
Treasury Bill Index(TM), with respect to the Market Neutral Fund, or the S&P
500, with respect to the Long-Short Equity Fund. Performance information may
also include evaluation of the Funds 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.

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<PAGE>

[THIS PAGE INTENTIONALLY LEFT BLANK]

<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 PROSPECTUS
REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING __________, 1998
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

INTRODUCTION...................................... 4
INVESTMENT OBJECTIVES AND POLICIES................ 4
INVESTMENT LIMITATIONS............................ 7
RISK FACTORS...................................... 8
MANAGEMENT........................................ 8
DISTRIBUTION OF SHARES............................ 10 BOSTON PARTNERS
HOW TO PURCHASE SHARES............................ 11 MARKET NEUTRAL PLUS FUND
HOW TO REDEEM AND EXCHANGE SHARES................. 13 (Institutional Shares)
NET ASSET VALUE................................... 17
DIVIDENDS AND DISTRIBUTIONS....................... 17
TAXES ......................................... 18
MULTI-CLASS STRUCTURE............................. 19
DESCRIPTION OF SHARES............................. 19
OTHER INFORMATION................................. 20

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 bp
Provident Distributors, Inc.
West Conshohocken, Pennsylvania BOSTON PARTNERS ASSET MANAGEMENT, L.P.

COUNSEL
Drinker Biddle & Reath LLP
Philadelphia, Pennsylvania

INDEPENDENT ACCOUNTANTS
PricewaterhouseCoopers
Philadelphia, Pennsylvania

<PAGE>

<TABLE>
<CAPTION>
BOSTON PARTNERS MARKET NEUTRAL FUND BP
BOSTON PARTNERS LONG-SHORT EQUITY FUND BOSTON PARTNERS ASSET MANAGEMENT, L.P.
(INSTITUTIONAL CLASS)

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

<S> <C>

+--------------+ (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, OR OTHER NAME(S) OF TRUSTEE(S)

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

+--------------+ Minimum initial investment of $2,500 Amount of investment $____________
3
Investment | Make the check payable to Boston Partners Market Neutral Fund or Boston Partners Long-Short Equity Fund,
Information: as applicable.
- ---------------+ 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 check. If not options are selected
OPTIONS: 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 below.
| 4 | I authorize the Transfer Agent to accept instructions from any persons to redeem or exchange shares in
| Telephone | my account(s) by telephone in accordance with the procedures and conditions set forth in the Fund's
| Redemption: | 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,
Boston Partners Micro Cap Fund or Boston
Partners Bond Fund.

- -------------- --------------------------------------------------------------------------------------------------------
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 fully authority and, if a natural person, I (we) am (are) of
| 6 | legal age to purchase shares pursuant to this Account Application, and I (we) have received a current
| | prospectus for the Fund in which I (we) am (are) investing.
| Signatures: | 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 ACCOUNT APPLICATION AND CHECK TO: THE BOSTON PARTNERS MARKET NEUTRAL FUND, OR
THE BOSTON PARTNERS LONG-SHORT EQUITY FUND
C/O PFPC INC.
P.O. BOX 8852
WILMINGTON, DE 19899-8852
</TABLE>
<PAGE>

THE RBB FUND, INC.

BOSTON PARTNERS MARKET NEUTRAL FUND
BOSTON PARTNERS LONG-SHORT EQUITY FUND
(INVESTOR SHARES)

CROSS REFERENCE SHEET
---------------------

<TABLE>
<CAPTION>
FORM N-1A ITEM LOCATION