Pricing of Fund Shares

Investor Class shares of the Funds (“Shares”) are priced at their net asset value (“NAV”). The NAV per share of each Fund is calculated as follows:

Each Fund’s NAV is calculated once daily at the close of regular trading hours on the New York Stock Exchange (“NYSE”) (generally 4:00 p.m. Eastern time) on each day the NYSE is open. The NYSE is generally open Monday through Friday, except national holidays. The Fund will effect purchases of Fund shares at the NAV next determined after receipt of your order or request in proper form. The Fund will effect redemptions of Fund shares at the NAV next calculated after receipt of your order in proper form.

A Fund’s equity securities listed on any national or foreign exchange market system will be valued at the last sale price, except for the National Association of Securities Dealers Automatic Quotation System (“NASDAQ”). Equity securities listed on NASDAQ will be valued at the official closing price. Equity securities traded in the over-the-counter market are valued at their closing prices. If there were no transactions on that day, securities traded principally on an exchange or on NASDAQ will be valued at the mean of the last bid and ask prices prior to the market close. Fixed income securities having a remaining maturity of 60 days or less are valued at amortized cost, which approximates market value. Fixed income securities having a remaining maturity of greater than 60 days are valued using an independent pricing service. When prices are not available from such securities or are deemed to be unreliable, securities may be valued by dealers who make markets in such securities. Foreign securities, currencies and other securities denominated in foreign currencies are translated into U.S. dollars at the exchange rate of such currencies against the U.S. dollar provided by a pricing service. All assets denominated in foreign currencies will be converted into U.S. dollars at the exchange rates in effect at the time of valuation. If a Fund holds foreign equity securities, the calculation of the Fund’s NAV will not occur at the same time as the determination of the value of the foreign equities securities in the Fund’s portfolio, since these securities are traded on foreign exchanges.

If market quotations are unavailable or deemed unreliable, securities will be valued in accordance with procedures adopted by the Company’s Board of Directors. In addition, the prices of foreign securities may be affected by events that occur after the close of a foreign market but before a Fund prices its shares. In such instances, a foreign security may be fair valued in accordance with procedures adopted by the Company’s Board of Directors. Relying on prices supplied by pricing services or dealers or using fair valuation involves the risk that the values used by a Fund to price its investments may be higher or lower than the values used by other investment companies and investors to price the same investments.

Investments in other open-end investment companies are valued based on the NAV of those investment companies (which may use fair value pricing as discussed in their prospectuses).

Market Timing

In accordance with the policy adopted by the Company’s Board of Directors, the Company discourages market timing and other excessive trading practices. Purchases should be made with a view to longer-term investment only. Excessive short-term (market timing) trading practices may disrupt portfolio management strategies, increase brokerage and administrative costs, harm Fund performance and result in dilution in the value of Fund shares held by long-term shareholders. The Company and the Adviser reserve the right to reject or restrict purchase requests from any investor. The Company and the Adviser will not be liable for any loss resulting from rejected purchase orders. To minimize harm to the Company and its shareholders (or the Adviser), the Company (or the Adviser) will exercise their right if, in the Company’s (or the Adviser’s) judgment, an investor has a history of excessive trading or if an investor’s trading, in the judgment of the Company or the Adviser, has been or may be disruptive to a Fund. No waivers of the provisions of the policy established to detect and deter market timing and other excessive trading activity are permitted that would harm the Fund and its shareholders or would subordinate the interests of the Fund and its shareholders to those of the Adviser or any affiliated person or associated person of the Adviser.

To deter excessive shareholder trading, each Fund generally limits the number of exchanges to six (6) times per year (one exchange per calendar month). For further information on redemptions and exchanges, please see the sections titled “Shareholder Information — Redemption of Fund Shares” and “Shareholder Information — Exchange Privilege.”

17

Pursuant to the policy adopted by the Board of Directors, the Adviser has developed criteria that it uses to identify trading activity that may be excessive. The Adviser reviews on a regular, periodic basis available information related to the trading activity in a Fund in order to assess the likelihood that the Fund may be the target of excessive trading. As part of its excessive trading surveillance process, the Adviser, on a periodic basis, examines transactions that exceed certain monetary thresholds or numerical limits within a period of time. If, in its judgment, the Adviser detects excessive, short-term trading, the Adviser may reject or restrict a purchase request and may further seek to close an investor’s account with the Fund. The Adviser may modify its surveillance procedures and criteria from time to time without prior notice regarding the detection of excessive trading or to address specific circumstances. The Adviser will apply the criteria in a manner that, in the Adviser’s judgment, will be uniform. There is no assurance that the Adviser will be able to identify market timers, particularly if they are investing through intermediaries.

Purchase of Fund Shares

Shares representing interests in the Funds are offered continuously for sale by PFPC Distributors, Inc. (the “Distributor”). The Board of Directors has approved a Distribution Agreement and adopted a separate Plan of Distribution for the shares (the “Plan”) pursuant to Rule 12b-1 under the Investment Company Act of 1940. Under the Plan, the Distributor is entitled to receive from the Funds 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 the Company’s Board of Directors and by the Distributor. Because these fees are paid out of the Funds’ assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of sales charges.

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 Funds’ 12b-1 Plan. Ongoing servicing and/or maintenance of the accounts of shareholders may include updating and mailing prospectuses and shareholder reports, responding to inquiries regarding shareholder accounts and acting as agent or intermediary between shareholders and the Funds or their service providers. The Distributor may delegate some or all of these functions to Service Organizations. See “Purchases Through Intermediaries” below.

The Plan obligates the Funds, 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 Funds 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 Company. Therefore, you should contact the Service Organization acting on your behalf concerning the fees (if any) charged in connection with a purchase or redemption of Shares and should read this Prospectus in light of the terms governing your accounts with the Service Organization. Service Organizations will be responsible for promptly transmitting client or customer purchase and redemption orders to the Company in accordance with their agreements with the Company and with clients or customers. Service Organizations or, if applicable, their designees that have entered into agreements with the Company or its agent may enter confirmed purchase orders on behalf of clients and customers, with payment to follow no later than the Company’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 Company 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 if the order is actually received by the Company in good order not later than the next business morning. If a purchase order is not received by the Fund in good order, PFPC Inc. (the “Transfer Agent”) will contact the financial intermediary to determine the status of the purchase order. Orders received by the Company in good order will be priced at the Fund’s NAV next computed after they are deemed to have been received by the Service Organization or its authorized designee.

The Company relies upon the integrity of Service Organizations to ensure that orders are timely and properly submitted. Each Fund cannot assure you that a Service Organization properly submitted to it all purchase and redemption orders received from the Service Organization’s customers before the time for determination of the Fund’s NAV in order to obtain that day’s price.

For administration, subaccounting, transfer agency and/or other services, the Adviser, the Distributor or their affiliates may pay Service Organizations and certain recordkeeping organizations a fee (the “Service Fee”) of the average

18

annual NAV of accounts with the Company 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.

General. You may also purchase Shares of each Fund at the NAV per share next calculated after your order is received by the Transfer Agent in proper form as described below. After an initial purchase is made, the Transfer Agent will set up an account for you on the Company records. The minimum initial investment in any Fund is $2,500 and the minimum additional investment is $100. The minimum initial and subsequent investment requirements may be reduced or waived from time to time. For purposes of meeting the minimum initial purchase, purchases by clients which are part of endowments, foundations or other related groups may be combined. You can only purchase Shares of the Fund on days the NYSE is open and through the means described below. Shares may be purchased by principals and employees of the Adviser and its subsidiaries and by their spouses and children either directly or through any trust that has the principal, employee, spouse or child as the primary beneficiaries, their individual retirement accounts, or any pension and profit-sharing plan of the Adviser and its subsidiaries without being subject to the minimum investment limitations.

Initial Investment By Mail. An account may be opened by completing and signing the application included with this Prospectus and mailing it to the Transfer Agent at the address noted below, together with a check ($2,500 minimum) payable to the Fund in which you would like to invest. Third party checks will not be accepted.

The name of the Fund to be purchased should be designated on the application and should appear on the check. Payment for the purchase of Shares received by mail will be credited to a shareholder’s account at the NAV per share of the Fund next determined after receipt of payment in good order.

Initial Investment By Wire. Shares of each Fund may be purchased by wiring federal funds to PNC Bank, N.A. (see instructions below). A completed application must be forwarded to the Transfer Agent at the address noted above under “Initial Investment by Mail” in advance of the wire. For each Fund, notification must be given to the Transfer Agent at (888) 261-4073 prior to 4:00 p.m., Eastern time, on the wire date. (Prior notification must also be received from investors with existing accounts.) Request account information and routing instructions by calling the Transfer Agent at (888) 261-4073. Funds should be wired to:

PNC Bank, N.A.

Philadelphia, Pennsylvania 19103

ABA# 0310-0005-3

Account # 86-1108-2507

F/B/O [name of fund]

Ref. (Account Number)

Shareholder or Account Name

Federal funds wire purchases will be accepted only on days when the NYSE and PNC Bank, N.A. are open for business.

Additional Investments. Additional investments may be made at any time (minimum additional investment $100) by purchasing Shares of any Fund at the NAV per Share of the Fund by mailing a check to the Transfer Agent at the address noted under “Initial Investment by Mail” (payable to [name of Fund]) or by wiring monies to PNC Bank, N.A. as outlined under “Initial Investment by Wire.” For each Fund, notification must be given to the Transfer Agent at (888) 261-4073 prior to 4:00 p.m., Eastern time, on the wire date. Initial and additional purchases made by check cannot be redeemed until payment of the purchase has been collected. This may take up to 15 calendar days.

Automatic Investment Plan. Additional investments in Shares of the Funds may be made automatically by authorizing the Transfer Agent to withdraw funds from your bank account through an Automatic Investment Plan ($100 minimum). Investors desiring to participate in an Automatic Investment Plan should call the Transfer Agent at (888) 261-4073.

Retirement Plans. Shares may be purchased in conjunction with individual retirement accounts (“IRAs”) and rollover IRAs. A $15.00 custodial maintenance fee is charged per IRA account per year. For further information as to applications and annual fees, contact the Transfer Agent at (888) 261- 4073. To determine whether the benefits of an IRA are available and/or appropriate, you should consult with a tax advisor.

19

Other Purchase Information. The Company reserves the right, in its sole discretion, to suspend the offering of Shares or to reject purchase orders when, in the judgment of management, such suspension or rejection is in the best interests of the Funds. Subject to Board of Directors’ discretion, the Adviser will monitor each Fund’s total assets and may decide to close any of the Funds at any time to new investments or to new accounts due to concerns that a significant increase in the size of a Fund may adversely affect the implementation of the Fund’s strategy. Subject to Board of Directors’ discretion, the Adviser may also choose to reopen a closed Fund to new investments at any time, and may subsequently close such Fund again should concerns regarding the Fund’s size recur. If a Fund closes to new investments, generally the closed Fund would be offered only to certain existing shareholders of the Fund and certain other persons, who are generally subject to cumulative, maximum purchase amounts, as follows:

Other persons who are shareholders of other Robeco Funds are not permitted to acquire Shares of the closed Fund by exchange. Distributions to all shareholders of the closed Fund will continue to be reinvested unless a shareholder elects otherwise. The Adviser, subject to the Board of Directors’ discretion, reserves the right to implement other purchase limitations at the time of closing, including limitations on current shareholders.

Purchases of the Funds’ Shares will be made in full and fractional shares of the Fund calculated to three decimal places.

The Company’s officers are authorized to waive the minimum initial and subsequent investment requirements.

Good Order. You must include complete and accurate required information on your purchase request. Please see “Purchase of Fund Shares” for instructions. Purchase requests not in good order may be rejected.

Customer Identification Program. Federal law requires the Company to obtain, verify and record identifying information, which may include the name, residential or business street address, date of birth (for an individual), social security or taxpayer identification number or other identifying information for each investor who opens or reopens an account with the Company. Applications without the required information, or without any indication that a social security or taxpayer identification number has been applied for, may not be accepted. After acceptance, to the extent permitted by applicable law or its customer identification program, the Company reserves the right (a) to place limits on transactions in any account until the identity of the investor is verified; or (b) to refuse an investment in a Company portfolio or to involuntarily redeem an investor’s Shares and close an account in the event that an investor’s identity is not verified. The Company and its agents will not be responsible for any loss in an investor’s account resulting from the investor’s delay in providing all required identifying information or from closing an account and redeeming an investor’s Shares when an investor’s identity cannot be verified.

Redemption of Fund Shares

Normally, your investment firm will send your request to redeem Shares to the Fund’s transfer agent. Consult your investment professional for more information. You can redeem some or all of your Fund shares directly through the Fund only if the account is registered in your name. All IRA shareholders must complete an IRA withdrawal form to redeem shares from their IRA account.

You may redeem Shares of the Funds at the next NAV calculated after a redemption request is received by the Transfer Agent in proper form. You can only redeem Shares on days the NYSE is open and through the means described below.

You may redeem Shares of each Fund by mail, or, if you are authorized, by telephone. The value of Shares redeemed may be more or less than the purchase price, depending on the market value of the investment securities held by a Fund. There is generally no charge for a redemption. However, with the exception of defined contribution plans, if a shareholder redeems Shares held for less than 60 days, a transaction fee of 1% of the NAV of the Shares redeemed at the time of redemption will be charged. For purposes of this redemption feature, Shares purchased first will be considered to be Shares first redeemed.

Redemption By Mail. Your redemption requests should be addressed to [name of Fund], c/o PFPC Inc., P.O. Box 9816, Providence, RI 02940; for overnight delivery, requests should be addressed to [name of Fund], c/o PFPC Inc., 101 Sabin Street, Pawtucket, RI 02860-1427 and must include:

20

Redemption By Telephone. In order to request a telephone redemption, you must have returned your account application containing a telephone election. To add a telephone redemption option to an existing account, contact the Transfer Agent by calling (888) 261-4073. Please note that IRA accounts are not eligible for telephone redemption.

Once you are authorized to utilize the telephone redemption option, a redemption of Shares may be requested by calling the Transfer Agent at (888) 261-4073 and requesting that the redemption proceeds be mailed to the primary registration address or wired per the authorized instructions. A wire charge of $7.50 is assessed and charged to the shareholder. If the telephone redemption option or the telephone exchange option is authorized, the Transfer Agent may act on telephone instructions from any person representing himself or herself to be a shareholder and believed by the Transfer Agent to be genuine. The Transfer Agent’s records of such instructions are binding and shareholders, not the Company or the Transfer Agent, bear the risk of loss in the event of unauthorized instructions reasonably believed by the Company or the Transfer Agent to be genuine. The Company and the Transfer Agent will employ reasonable procedures to confirm that instructions communicated are genuine and, if it does not, it may be liable for any losses due to unauthorized or fraudulent instructions. The procedures employed by the Company and the Transfer Agent in connection with transactions initiated by telephone include tape recording of telephone instructions and requiring some form of personal identification prior to acting upon instructions received by telephone.

Systematic Withdrawal Plan. If your account has a value of at least $10,000, you may establish a Systematic Withdrawal Plan and receive regular periodic payments. A request to establish a Systematic Withdrawal Plan must be submitted in writing to the Transfer Agent at P.O. Box 9816, Providence, RI 02940. Each withdrawal redemption will be processed on or about the 25th of the month and mailed as soon as possible thereafter. There are no service charges for maintenance; the minimum amount that you may withdraw each period is $100. (This is merely the minimum amount allowed and should not be mistaken for a recommended amount.) The holder of a Systematic Withdrawal Plan will have any income dividends and any capital gains distributions reinvested in full and fractional shares at NAV. To provide funds for payment, Shares will be redeemed in such amounts as are necessary at the redemption price. The systematic withdrawal of Shares may reduce or possibly exhaust the Shares in your account, particularly in the event of a market decline. As with other redemptions, a systematic withdrawal payment is a sale for federal income tax purposes. Payments made pursuant to a Systematic Withdrawal Plan cannot be considered as actual yield or income since part of such payments may be a return of capital.

You will ordinarily not be allowed to make additional investments of less than the aggregate annual withdrawals under the Systematic Withdrawal Plan during the time you have the plan in effect and, while a Systematic Withdrawal Plan is in effect, you may not make periodic investments under the Automatic Investment Plan. You will receive a confirmation of each transaction and the Share and cash balance remaining in your plan. The plan may be terminated on written notice by the shareholder or by a Fund and will terminate automatically if all Shares are liquidated or withdrawn from the account or upon the death or incapacity of the shareholder. You may change the amount and schedule of withdrawal payments or suspend such payments by giving written notice to the Funds’ transfer agent at least ten Business Days prior to the end of the month preceding a scheduled payment.

Involuntary Redemption. The Funds reserve the right to redeem a shareholder’s account in any Fund at any time the value of the account in such Fund 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 in a Fund is less than $500 and will be allowed 30 days to make additional investments before the redemption is processed.

21

Other Redemption Information. Redemption proceeds for Shares of the Funds recently purchased by check may not be distributed until payment for the purchase has been collected, which may take up to fifteen days from the purchase date. Shareholders can avoid this delay by utilizing the wire purchase option.

Other than as described above, payment of the redemption proceeds will be made within seven days after receipt of an order for a redemption. The Company may suspend the right of redemption or postpone the date at times when the NYSE is closed or under any emergency circumstances as determined by the SEC.

If the Board of Directors determines that it would be detrimental to the best interests of the remaining shareholders of the Funds to make payment wholly or partly in cash, redemption proceeds may be paid in whole or in part by an in-kind distribution of readily marketable securities held by a Fund instead of cash in conformity with applicable rules of the SEC. Investors generally will incur brokerage charges on the sale of portfolio securities so received in the payment of redemptions. The Company has elected, however, 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 NAV during any 90-day period for any one shareholder of a Fund.

Proper Form. You must include complete and accurate required information on your redemption request. Please see “Redemption of Fund Shares” for instructions. Redemption requests not in proper form may be delayed.

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 Investor Class Shares of any Robeco Investment Fund for Investor Class Shares of another Robeco Investment Fund, up to six (6) times per year (one exchange per calendar month). Such an exchange will be effected at the NAV of the exchanged Investor Class Shares and the NAV of the Investor Class Shares to be acquired next determined after PFPC’s receipt of a request for an exchange. An exchange of Fund 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 a transaction fee of 1.00%. An exchange of Shares will be treated as a sale for federal income tax purposes. A shareholder may make an exchange by sending a written request to the Transfer Agent or, if authorized, by telephone (see “Redemption by Telephone” above). Defined contribution plans are not subject to the above exchange limitations, including any applicable redemption fee.

If the exchanging shareholder does not currently own Investor Class Shares of the 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. See “Redemption by Mail” for information on signature guarantees. The exchange privilege may be modified or terminated at any time, or from time to time, by the Funds, upon 60 days’ written notice to shareholders.

If a shareholder wants to exchange shares into a new account in a Fund, the dollar value of the Shares acquired must equal or exceed the Fund’s minimum investment requirement for a new account. If a shareholder wants to exchange shares into an existing account, the dollar value of the shares must equal or exceed the Fund’s minimum investment requirement for additional investments. If an amount remains in the Fund from which the exchange is being made that is below the minimum account value required, the account will be subject to involuntary redemption.

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, which may potentially disrupt the management of the Funds and increase transaction costs, the Funds have established a policy of limiting excessive exchange activity. Shareholders are entitled to six (6) exchange redemptions (one exchange per calendar month) from each Fund during any twelve-month period. Notwithstanding these limitations, the Funds reserve the right to reject any purchase request (including exchange purchases from other Robeco Investment Funds) that is deemed to be disruptive to efficient portfolio management.