(RIVERSOURCE INVESTMENTS LOGO)

(THREADNEEDLE LOGO)

PROSPECTUS SUPPLEMENT -- JAN. 22, 2009*

<Table>
<Caption>
FUND PROSPECTUS DATE FORM #
- --------------------------------------------------------------

RiverSource 120/20 Contrarian
Equity Fund June 27, 2008 S-6519-99 C
RiverSource Absolute Return
Currency and Income Fund Dec. 30, 2008 S-6502-99 G
RiverSource Balanced Fund Nov. 28, 2008 S-6326-99 AD
RiverSource California Tax-
Exempt Fund Oct. 30, 2008 S-6328-99 AH
RiverSource Disciplined
Equity Fund Sept. 29, 2008 S-6263-99 H
RiverSource Disciplined
International Equity Fund Dec. 30, 2008 S-6506-99 E
RiverSource Disciplined Large
Cap Growth Fund Nov. 28, 2008 S-6285-99 D
RiverSource Disciplined Large
Cap Value Fund Nov. 28, 2008 S-6523-99 C
RiverSource Disciplined Small
and Mid Cap Equity Fund Sept. 29, 2008 S-6505-99 E
RiverSource Disciplined Small
Cap Value Fund Sept. 29, 2008 S-6397-99 E
RiverSource Diversified Bond
Fund Oct. 30, 2008 S-6495-99 AC
RiverSource Diversified
Equity Income Fund Nov. 28, 200 S-6475-99 AD
RiverSource Dividend
Opportunity Fund Aug. 29, 2008 S-6341-99 AD
RiverSource Emerging Markets
Bond Fund Dec. 30, 2008 S-6398-99 E
RiverSource Equity Value Fund May 30, 2008 S-6382-99 W
RiverSource Floating Rate
Fund Sept. 29, 2008 S-6501-99 E
RiverSource Global Bond Fund Dec. 30, 2008 S-6309-99 AE
RiverSource Global Technology
Fund Dec. 30, 2008 S-6395-99 N
RiverSource Growth Fund Sept. 29, 2008 S-6455-99 AD
RiverSource High Yield Bond
Fund July 30, 2008 S-6370-99 AD
RiverSource Income Builder
Basic Income Fund March 31, 2008 S-6394-99 E
RiverSource Income Builder
Enhanced Income Fund March 31, 2008 S-6394-99 E
RiverSource Income Builder
Moderate Income Fund March 31, 2008 S-6394-99 E
RiverSource Income
Opportunities Fund Sept. 29, 2008 S-6266-99 H
RiverSource Inflation
Protected Securities Fund Sept. 29, 2008 S-6280-99 G
RiverSource Intermediate Tax-
Exempt Fund Jan. 29, 2008 S-6355-99 T
RiverSource Large Cap Equity
Fund Sept. 29, 2008 S-6244-99 J
RiverSource Large Cap Value
Fund Sept. 29, 2008 S-6246-99 J
RiverSource Limited Duration
Bond Fund Sept. 29, 2008 S-6265-99 H
RiverSource Mid Cap Growth
Fund Jan. 29, 2008 S-6426-99 AD
RiverSource Mid Cap Value
Fund Nov. 28, 2008 S-6241-99 K
RiverSource Minnesota Tax-
Exempt Fund Oct. 30, 2008 S-6328-99 AH
RiverSource New York Tax-
Exempt Fund Oct. 30, 2008 S-6328-99 AH
RiverSource Partners
Aggressive Growth Fund July 30, 2008 S-6260-99 J
RiverSource Partners
Fundamental Value Fund July 30, 2008 S-6236-99 L
RiverSource Partners
International Select Growth
Fund Dec. 30, 2008 S-6243-99 M
RiverSource Partners
International Select Value
Fund Dec. 30, 2008 S-6242-99 M
RiverSource Partners
International Small Cap
Fund Dec. 30, 2008 S-6258-99 K
RiverSource Partners Select
Value Fund July 30, 2008 S-6240-99 K
RiverSource Partners Small
Cap Equity Fund July 30, 2008 S-6237-99 L
RiverSource Partners Small
Cap Growth Fund May 30, 2008 S-6301-99 L
RiverSource Partners Small
Cap Value Fund July 30, 2008 S-6239-99 L
RiverSource Portfolio Builder
Aggressive Fund March 31, 2008 S-6282-99 G
RiverSource Portfolio Builder
Conservative Fund March 31, 2008 S-6282-99 G
RiverSource Portfolio Builder
Moderate Aggressive Fund March 31, 2008 S-6282-99 G
RiverSource Portfolio Builder
Moderate Conservative Fund March 31, 2008 S-6282-99 G
RiverSource Portfolio Builder
Moderate Fund March 31, 2008 S-6282-99 G
RiverSource Portfolio Builder
Total Equity Fund March 31, 2008 S-6282-99 G
RiverSource Precious Metals
and Mining Fund May 30, 2008 S-6142-99 AE
RiverSource Real Estate Fund Aug. 29, 2008 S-6281-99 G
RiverSource Retirement Plus
2010 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2015 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2020 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2025 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2030 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2035 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2040 Fund June 27, 2008 S-6507-99 E
RiverSource Retirement Plus
2045 Fund June 27, 2008 S-6507-99 E
RiverSource Short Duration
U.S. Government Fund July 30, 2008 S-6042-99 AE
RiverSource Small Cap
Advantage Fund May 30, 2008 S-6427-99 N
RiverSource Small Company
Index Fund March 31, 2008 S-6357-99 U
RiverSource Strategic
Allocation Fund Nov. 28, 2008 S-6141-99 AE
RiverSource Strategic Income
Allocation Fund Nov. 28, 2008 S-6287-99 D
RiverSource Tax-Exempt Bond
Fund Jan. 29, 2008 S-6310-99 AE
RiverSource Tax-Exempt High
Income Fund Jan. 29, 2008 S-6430-99 AE
RiverSource U.S. Government
Mortgage Fund July 30, 2008 S-6245-99 K
Threadneedle Emerging Markets
Fund Dec. 30, 2008 S-6354-99 V
Threadneedle European Equity
Fund Dec. 30, 2008 S-6006-99 N
Threadneedle Global Equity
Fund Dec. 30, 2008 S-6334-99 AG
Threadneedle Global Equity
Income Fund Dec. 30, 2008 S-6334-99 AG
Threadneedle Global Extended
Alpha Fund Dec. 30, 2008 S-6334-99 AG
Threadneedle International
Opportunity Fund Dec. 30, 2008 S-6140-99 AG
</Table>

- --------------------------------------------------------------------------------
S-6141-10 A (1/09)
* Valid until Dec. 30, 2009

Effective February 9, 2009, the section of prospectus "Initial Sales
Charge -- Waiver of the sales charge for Class A shares" is replaced with the
following:

INITIAL SALES CHARGE -- WAIVERS OF THE SALES CHARGE FOR CLASS A SHARES. Sales
charges do not apply to:
- current or retired Board members, officers or employees of the funds or
RiverSource Investments or its affiliates, their spouses or domestic
partners, children, parents and their spouse's or domestic partner's
parents.
- current or retired Ameriprise Financial Services, Inc. financial
advisors, employees of financial advisors, their spouses or domestic
partners, children, parents and their spouse's or domestic partner's
parents.
- registered representatives and other employees of financial institutions
having a selling agreement with the distributor, including their spouses,
domestic partners, children, parents and their spouse's or domestic
partner's parents.
- portfolio managers employed by subadvisers of the funds, including their
spouses or domestic partners, children, parents and their spouse's or
domestic partner's parents.
- partners and employees of outside legal counsel to the funds or the
funds' directors or trustees who regularly provide advice and services to
the funds, or to their directors or trustees.
- direct rollovers from qualified employee benefit plans, provided that the
rollover involves a transfer to Class A shares in the same fund.
- purchases made:
- with dividend or capital gain distributions from a fund or from the
same class of another fund in the RiverSource complex of funds;
- through or under a wrap fee product or other investment product
sponsored by a financial intermediary that charges an account
management fee that has, or clears trades through a financial
intermediary that has, a selling agreement with the distributor;
- through state sponsored college savings plans established under Section
529 of the Internal Revenue Code;
- through bank trust departments.
- purchases made through "eligible employee benefit plans" created under
section 401(a), 401(k), 457 and 403(b) which:
- have at least $1 million in plan assets at the time of investment;
- have a plan level or omnibus account that is maintained with the fund
or its transfer agent; and
- transact directly with the fund or its transfer agent through a third
party administrator or third party recordkeeper.

For more information regarding waivers of sales charges for Class A purchases,
please see the SAI.

The distributor may, in its sole discretion, authorize the waiver of sales
charges for additional purchases or categories of purchases. Policies related to
reducing or waiving the sales charge may be modified or withdrawn at any time.

Unless you provide your financial intermediary with information in writing about
all of the factors that may count toward a waiver of the sales charge, there can
be no assurance that you will receive all of the waivers for which you may be
eligible. You should request that your financial intermediary provide this
information to the fund when placing your purchase order.

Because the current prospectus is available on the funds' website at
riversource.com free of charge, information regarding breakpoint discounts is
not separately disclosed on the website.

S-6141-10 A (1/09)
* Valid until Dec. 30, 2009

Prospectus
(THREADNEEDLE LOGO)

THREADNEEDLE
EMERGING MARKETS FUND

PROSPECTUS DEC. 30, 2008

THREADNEEDLE EMERGING MARKETS FUND SEEKS TO PROVIDE
SHAREHOLDERS WITH LONG-TERM CAPITAL GROWTH.

Classes A, B, C, I, R4 and R5

As with all mutual funds, the Securities and Exchange
Commission has not approved or disapproved these securities or
passed upon the adequacy of this prospectus. Any
representation to the contrary is a criminal offense.

You may qualify for sales charge discounts on purchases of Class A
shares. Please notify your financial institution if you have other
accounts holding shares of RiverSource funds to determine whether you
qualify for a sales charge discount. See "Buying and Selling Shares" for
more information.

NOT FDIC INSURED - MAY LOSE VALUE - NO BANK GUARANTEE

TABLE OF CONTENTS

<Table>

THE FUND.......................................... 3P
Objective......................................... 3p
Principal Investment Strategies................... 3p
Principal Risks................................... 5p
Past Performance.................................. 7p
Fees and Expenses................................. 12p
Other Investment Strategies and Risks............. 14p
Fund Management and Compensation.................. 15p
FINANCIAL HIGHLIGHTS.............................. 17P
BUYING AND SELLING SHARES......................... S.1
Description of Share Classes...................... S.2
Investment Options -- Classes of Shares......... S.2
Sales Charges................................... S.5
Opening an Account.............................. S.12
Exchanging or Selling Shares...................... S.15
Exchanges....................................... S.17
Selling Shares.................................. S.19
VALUING FUND SHARES............................... S.20
DISTRIBUTIONS AND TAXES........................... S.21
GENERAL INFORMATION............................... S.23
</Table>

RIVERSOURCE COMPLEX OF FUNDS

The RiverSource complex of funds includes a comprehensive array of funds from
RiverSource Investments, including several Seligman funds. RiverSource
Investments has also partnered with a number of professional investment
managers, including its affiliate, Threadneedle Investments, to expand the array
of funds offered in the RiverSource complex. RiverSource funds, RiverSource
Partners funds and Threadneedle funds share the same Board of Directors/Trustees
(the Board), and the same policies and procedures including those set forth in
the service section. Although the Seligman funds share the same Board, they do
not currently have the same policies and procedures, and may not be exchanged
for shares of the RiverSource funds, RiverSource Partners funds or Threadneedle
funds. Please see the Statement of Additional Information (SAI) for a complete
list of mutual funds included in the RiverSource complex of funds.

RiverSource Variable Portfolio Funds and Seligman (Variable) Portfolio Funds are
sold exclusively as underlying investment options of variable insurance policies
and annuity contracts offered by affiliated and unaffiliated insurance
companies.

- --------------------------------------------------------------------------------
2P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

THE FUND

OBJECTIVE

Threadneedle Emerging Markets Fund (formerly RiverSource Emerging Markets Fund)
(the Fund) seeks to provide shareholders with long-term capital growth. Because
any investment involves risk, there is no assurance this objective can be
achieved. Only shareholders can change the Fund's objective.

PRINCIPAL INVESTMENT STRATEGIES

The Fund's assets are primarily invested in equity securities of emerging
markets companies. Emerging markets are countries characterized as developing or
emerging by either the World Bank or the United Nations. Under normal market
conditions, at least 80% of the Fund's net assets will be invested in securities
of companies that are located in emerging markets countries, or that earn 50% or
more of their total revenues from goods or services produced in emerging market
countries or from sales made in emerging markets countries. The Fund will
provide shareholders with at least 60 days' notice of any change in the 80%
policy.

RiverSource Investments, LLC (RiverSource Investments) serves as the investment
manager to the Fund and is responsible for oversight of the subadviser,
Threadneedle International Limited (Threadneedle), an indirect wholly-owned
subsidiary of Ameriprise Financial, Inc.

Threadneedle chooses investments by:

- - Deploying an integrated approach to equity research that incorporates regional
analyses, a global sector strategy, and stock specific perspectives.

- - Conducting detailed research on companies in a consistent strategic and
macroeconomic framework.

- - Looking for catalysts of change and identifying the factors driving markets,
which will vary over economic and market cycles.

- - Implementing rigorous risk control processes that seek to ensure that the risk
and return characteristics of the Fund's portfolio are consistent with
established portfolio management parameters.

The Fund's portfolio management team constructs the portfolio by selecting what
it considers to be the best stocks in each industry sector, based on return on
invested capital analysis, growth and valuation. The Fund's sector exposure
generally reflects the global macroeconomic environment, the outlook for each
sector and the relative valuation of the stocks among the sectors.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 3P

The Fund's portfolio management team constructs the portfolio by investing in
most of the stocks on two core lists of holdings, the Largest Companies List and
the Preferred List. In addition, the portfolio will hold other securities
selected by the portfolio management team. These discretionary holdings will
typically make up a much smaller portion of the Fund.

- - The Largest Companies List includes the largest stocks in the Fund's
benchmark, the Morgan Stanley Capital International (MSCI) Emerging Markets
Index. Threadneedle's research on sectors and specific companies is used to
determine recommended weightings for each stock.

- - The Preferred List includes the stocks not included in the Largest Companies
List that represent the best ideas generated by Threadneedle's research
analysts. Stocks on the Preferred List are selected by:

- Analyzing returns on invested capital for the largest companies within each
sector;

- Assessing valuations; and

- Evaluating one or more of the following: balance sheets and cash flows, the
demand for a company's products or services, its competitive position, or
its management.

The Fund will normally be overweight in the stocks on the Preferred List
compared to the benchmark.

- - Discretionary holdings are selected by the individual portfolio management
team based on the same criteria used to generate the Preferred List. These
stocks are assigned ratings based on their perceived ability to outperform
within their sector. The team typically selects the highest rated stocks
outside the core category.

A number of factors may prompt the portfolio management team to sell securities.
A sale may result from a change in the composition of the Fund's benchmark or a
change in sector strategy. A sale may also be prompted by factors specific to a
stock, such as valuation or company fundamentals.

The Fund will normally have exposure to foreign currencies. The portfolio
management team closely monitors the Fund's exposure to foreign currency. From
time to time the team may use forward currency transactions or other derivative
instruments to hedge against currency fluctuations.

- --------------------------------------------------------------------------------
4P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

PRINCIPAL RISKS

This Fund is designed for long-term investors with above-average risk tolerance.
Please remember that with any mutual fund investment you may lose money.
Principal risks associated with an investment in the Fund include:

ACTIVE MANAGEMENT RISK. The Fund is actively managed and its performance
therefore will reflect in part the ability of the portfolio managers to select
securities and to make investment decisions that are suited to achieving the
Fund's investment objective. Due to its active management, the Fund could
underperform other mutual funds with similar investment objectives.

DERIVATIVES RISK. Derivatives are financial instruments that have a value which
depends upon, or is derived from, the value of something else, such as one or
more underlying securities, pools of securities, options, futures, indexes or
currencies. Gains or losses involving derivative instruments may be substantial,
because a relatively small price movement in the underlying security(ies),
instrument, currency or index may result in a substantial gain or loss for the
Fund. Derivative instruments in which the Fund invests will typically increase
the Fund's exposure to Principal Risks to which it is otherwise exposed, and may
expose the Fund to additional risks, including counterparty credit risk,
leverage risk, hedging risk, correlation risk, and liquidity risk.

Counterparty credit risk is the risk that a counterparty to the derivative
instrument becomes bankrupt or otherwise fails to perform its obligations due to
financial difficulties, and the Fund may obtain no recovery of its investment or
may only obtain a limited recovery, and any recovery may be delayed.

Hedging risk is the risk that derivative instruments used to hedge against an
opposite position may offset losses, but they may also offset gains.

Correlation risk is related to hedging risk and is the risk that there may be an
incomplete correlation between the hedge and the opposite position, which may
result in increased or unanticipated losses.

Liquidity risk is the risk that the derivative instrument may be difficult or
impossible to sell or terminate, which may cause the Fund to be in a position to
do something the investment manager would not otherwise choose, including
accepting a lower price for the derivative instrument, selling other investments
or foregoing another, more appealing investment opportunity.

Leverage risk is the risk that losses from the derivative instrument may be
greater than the amount invested in the derivative instrument.

Certain derivatives have the potential for unlimited losses, regardless of the
size of the initial investment. See the SAI for more information on derivative
instruments and related risks.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 5P

RISKS OF FOREIGN INVESTING. Foreign securities are securities of issuers based
outside the United States. An issuer is deemed to be based outside the United
States if it is organized under the laws of another country. Foreign securities
are primarily denominated in foreign currencies. In addition to the risks
normally associated with domestic securities of the same type, foreign
securities are subject to the following foreign risks:

Country risk includes the political, economic, and other conditions of the
country. These conditions include lack of publicly available information, less
government oversight (including lack of accounting, auditing, and financial
reporting standards), the possibility of government-imposed restrictions, and
even the nationalization of assets. The liquidity of foreign investments may be
more limited than for most U.S. investments, which means that, at times it may
be difficult to sell foreign securities at desirable prices.

Currency risk results from the constantly changing exchange rate between local
currency and the U.S. dollar. Whenever the Fund holds securities valued in a
foreign currency or holds the currency, changes in the exchange rate add to or
subtract from the value of the investment.

Custody risk refers to the process of clearing and settling trades. It also
covers holding securities with local agents and depositories. Low trading
volumes and volatile prices in less developed markets make trades harder to
complete and settle. Local agents are held only to the standard of care of the
local market. Governments or trade groups may compel local agents to hold
securities in designated depositories that are not subject to independent
evaluation. The less developed a country's securities market is, the greater the
likelihood of problems occurring.

Emerging markets risk includes the dramatic pace of change (economic, social and
political) in these countries as well as the other considerations listed above.
These markets are in early stages of development and are extremely volatile.
They can be marked by extreme inflation, devaluation of currencies, dependence
on trade partners, and hostile relations with neighboring countries.

GEOGRAPHIC CONCENTRATION RISK. The Fund may be particularly susceptible to
economic, political or regulatory events affecting companies and countries
within the specific geographic region in which the Fund focuses its investments.
Currency devaluations could occur in countries that have not yet experienced
currency devaluation to date, or could continue to occur in countries that have
already experienced such devaluations. As a result, the Fund may be more
volatile than a more geographically diversified fund.

ISSUER RISK. An issuer may perform poorly, and therefore, the value of its
stocks and bonds may decline. Poor performance may be caused by poor management
decisions, competitive pressures, breakthroughs in technology, reliance on
suppliers, labor problems or shortages, corporate restructurings, fraudulent
disclosures or other factors.

- --------------------------------------------------------------------------------
6P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

MARKET RISK. The market value of securities may fall or fail to rise. Market
risk may affect a single issuer, sector of the economy, industry, or the market
as a whole. The market value of securities may fluctuate, sometimes rapidly and
unpredictably. This risk is generally greater for small and mid-sized companies,
which tend to be more vulnerable to adverse developments. In addition, focus on
a particular style, for example, investment in growth or value securities, may
cause the Fund to underperform other mutual funds if that style falls out of
favor with the market.

SECTOR RISK. Investments that are concentrated in a particular issuer,
geographic region or sector will be more susceptible to changes in price. The
more a fund diversifies across sectors, the more it spreads risk and potentially
reduces the risks of loss and volatility.

SMALL AND MID-SIZED COMPANY RISK. Investments in small and medium companies
often involve greater risks than investments in larger, more established
companies because small and medium companies may lack the management experience,
financial resources, product diversification, experience and competitive
strengths of larger companies. Additionally, in many instances the securities of
small and medium companies are traded only over-the-counter or on regional
securities exchanges and the frequency and volume of their trading is
substantially less and may be more volatile than is typical of larger companies.

PAST PERFORMANCE

The following bar chart and table provide some illustration of the risks of
investing in the Fund by showing, respectively:

- - how the Fund's performance has varied for each full calendar year shown on the
bar chart; and

- - how the Fund's average annual total returns compare to recognized indexes
shown on the table.

Both the bar chart and the table assume that all distributions have been
reinvested. The performance of different classes varies because of differences
in sales charges and other fees and expenses. How the Fund has performed in the
past (before and after taxes) does not indicate how the Fund will perform in the
future. Performance reflects any fee waivers/expense caps in effect for the
periods reported. In the absence of such fee waivers/expense caps, performance
would have been lower. See "Fees and Expenses" for any current fee
waivers/expense caps.

Bar Chart. Class A share information is shown in the bar chart; the sales charge
for Class A shares is not reflected in the bar chart.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 7P

Table. The table shows total returns from hypothetical investments in Class A,
Class B, Class C, Class I, Class R4 and Class R5 shares of the Fund. These
returns are compared to the indexes shown for the same periods. For purposes of
the performance calculation in the table we assumed:

- - the maximum sales charge for Class A shares;

- - sales at the end of the period and deduction of the applicable contingent
deferred sales charge (CDSC) for Class B and Class C shares;

- - no sales charge for Class I, Class R4 and Class R5 shares; and

- - with the exception of Class A shares, no adjustments for taxes paid by an
investor on the reinvested income and capital gains.

- --------------------------------------------------------------------------------
8P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

AFTER-TAX RETURNS

After-tax returns are shown only for Class A shares. After-tax returns for the
other classes will vary. After-tax returns are calculated using the highest
historical individual federal marginal income tax rate and do not reflect the
impact of state and local taxes. Actual after-tax returns will depend on your
tax situation and most likely will differ from the returns shown in the table.
If you hold your shares in a tax-deferred account, such as a 401(k) plan or an
IRA, the after-tax returns do not apply to you since you will not incur taxes
until you begin to withdraw from your account.

The return after taxes on distributions for a period may be the same as the
return before taxes for the same period if there were no distributions or if the
distributions were small. The return after taxes on distributions and sale of
Fund shares for a period may be greater than the return before taxes for the
same period if there was a tax loss realized on sale of Fund shares. The benefit
of the tax loss (since it can be used to offset other gains) may result in a
higher return.

CLASS A SHARE PERFORMANCE
(BASED ON CALENDAR YEARS)

(BAR CHART)

<Table>

-30.26% +79.03% -33.03% -3.85% -3.06% +40.60% +24.44% +34.10% +34.25% +37.23%

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

During the periods shown in the bar chart, the highest return for a calendar
quarter was +37.49% (quarter ended Dec. 31, 1999) and the lowest return for a
calendar quarter was -27.03% (quarter ended Sept. 30, 1998).

The 5.75% sales charge applicable to Class A shares of the Fund is not reflected
in the bar chart; if reflected, returns would be lower than those shown. The
performance of other classes may vary from that shown because of differences in
expenses.

The Fund's Class A year-to-date return at Sept. 30, 2008 was -36.39%.

The Fund formerly was a "feeder" fund in a master/feeder arrangement where the
Fund invested all of its assets in a corresponding "master" fund with an
identical investment objective and investment strategies. As of Nov. 8, 2005,
the Fund became a stand-alone fund that invests directly in a portfolio of
securities. The information shown in the table and in the financial highlights
for the Fund includes the activity of the Fund when it was a feeder in a
master/feeder arrangement.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 9P

AVERAGE ANNUAL TOTAL RETURNS (FOR PERIODS ENDED DEC. 31, 2007)

<Table>
<Caption>
SINCE SINCE
INCEPTION INCEPTION
1 YEAR 5 YEARS 10 YEARS (CLASS C) (CLASS I)

Threadneedle Emerging
Markets Fund:
Class A
Return before taxes +29.37% +32.44% +12.34% N/A N/A
Return after taxes on
distributions +21.76% +29.38% +11.02% N/A N/A
Return after taxes on
distributions and sale
of fund shares +20.99% +27.63% +10.40% N/A N/A
Class B
Return before taxes +31.20% +32.83% +12.04% N/A N/A
Class C
Return before taxes +35.24% +32.98% N/A +15.28%(a) N/A
Class I
Return before taxes +37.82% N/A N/A N/A +30.48%(b)
Class R4
Return before taxes +37.55% +34.27% +13.15% N/A N/A
MSCI Emerging Markets
Index (reflects no
deduction for fees,
expenses or taxes) +39.78% +37.46% +14.53%(c)+17.71%(c) +32.00%(d)
Lipper Emerging Markets
Funds Index +36.25% +36.33% +13.98%(c)+17.32%(c) +30.71%(d)
</Table>

(a) Inception date is June 26, 2000.
(b) Inception date is March 4, 2004.
(c) Measurement period started July 1, 2000.
(d) Measurement period started March 1, 2004.

The Morgan Stanley Capital International (MSCI) Emerging Markets Index, an
unmanaged market capitalization-weighted index, is designed to measure equity
market performance in the global emerging markets. The index reflects
reinvestment of all distributions and changes in market prices.

The Lipper Emerging Markets Funds Index includes the 30 largest emerging markets
funds tracked by Lipper Inc. The index's returns include net reinvested
dividends. The Fund's performance is currently measured against this index for
purposes of determining the performance incentive adjustment. See "Fund
Management and Compensation" for more information.

- --------------------------------------------------------------------------------
10P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

Past performance for Class R5 for the period prior to the beginning of
operations for that class may be calculated based on the performance of Class
R4. The blended class performance will be adjusted to reflect differences in
sales charges, but not differences in annual Fund operating expenses (for
example, 12b-1 fees). The use of blended performance generally results in a
presentation of higher performance for classes with higher operating expenses
than those of the class with which they are blended, and a presentation of lower
performance for classes with lower operating expenses than those of the class
with which they are blended.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 11P

FEES AND EXPENSES

Fund investors pay various expenses. The table below describes the fees and
expenses that you may pay if you buy and hold shares of the Fund. Expenses are
based on the Fund's most recent fiscal year.

SHAREHOLDER FEES (FEES PAID DIRECTLY FROM YOUR INVESTMENT)

<Table>
<Caption>
CLASS I
CLASS R4
CLASS A CLASS B CLASS C CLASS R5

Maximum sales charge (load) imposed
on purchases (as a percentage of
offering price) 5.75%(a) None None None
Maximum deferred sales charge
(load) imposed on sales (as a
percentage of offering price at
time of purchase) None(b) 5% 1% None
</Table>

ANNUAL FUND OPERATING EXPENSES (EXPENSES THAT ARE DEDUCTED FROM FUND ASSETS)

<Table>
<Caption>
AS A PERCENTAGE OF AVERAGE DAILY NET ASSETS:

CLASS A CLASS B CLASS C

Management fees(c) 1.16% 1.16% 1.16%
Distribution and/or service (12b-1)
fees 0.25% 1.00% 1.00%
Other expenses(d) 0.46% 0.46% 0.47%
Total annual fund operating expenses 1.87% 2.62% 2.63%
Fee waiver/expense reimbursement 0.00% 0.00% 0.00%
Total annual (net) fund operating
expenses(e) 1.87% 2.62% 2.63%
<Caption>
CLASS I CLASS R4 CLASS R5

Management fees(c) 1.16% 1.16% 1.16%
Distribution and/or service (12b-1)
fees 0.00% 0.00% 0.00%
Other expenses(d) 0.26% 0.57% 0.31%
Total annual fund operating expenses 1.42% 1.73% 1.47%
Fee waiver/expense reimbursement 0.00% 0.01% 0.00%
Total annual (net) fund operating
expenses(e) 1.42% 1.72% 1.47%
</Table>

(a) This charge may be reduced depending on the value of your total investments
in RiverSource Funds. See "Sales Charges."
(b) A 1% CDSC may be assessed on Class A shares sold without a sales charge
within 18 months after purchase. See "Sales Charges."
(c) Includes the impact of a performance incentive adjustment fee that increased
the management fee by 0.08% for the most recent fiscal year. The index
against which the Fund's performance is measured for purposes of determining
the performance incentive adjustment is the Lipper Emerging Markets Funds
Index. See "Fund Management and Compensation" for more information.
(d) Other expenses include an administrative services fee, a transfer agency fee
(for all classes except Class I), a custody fee, other nonadvisory expenses
and a plan administration services fee (for Class R4). Other expenses may
also include fees and expenses of affiliated and unaffiliated funds
(acquired funds) which the Fund indirectly bears when it invests in the
acquired funds. The impact of these acquired funds fees and expenses for the
most recent fiscal period was less than 0.01%. Because acquired funds will
have varied expense and fee levels and the Fund may own different
proportions of acquired funds at different times, the amount of fees and
expenses incurred by the Fund with respect to such investments will vary.
(e) The investment manager and its affiliates have contractually agreed to waive
certain fees and to absorb certain expenses until Oct. 31, 2009, unless
sooner terminated at the discretion of the Fund's Board. Any amounts waived
will not be reimbursed by the Fund. Under this agreement, net fund expenses
(excluding fees and expenses of acquired funds), before giving effect to any
performance incentive adjustment, will not exceed 1.64% for Class R4.

- --------------------------------------------------------------------------------
12P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

EXAMPLES

These examples are intended to help you compare the cost of investing in the
Fund with the cost of investing in other mutual funds.

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

<Table>
<Caption>
1 YEAR 3 YEARS 5 YEARS 10 YEARS

Class A(a) $754 $1,129 $1,529 $2,644
Class B $765(b) $1,215(b) $1,591(b) $2,775(c)
Class C $366(b) $ 818 $1,396 $2,967
Class I $145 $ 450 $ 777 $1,707
Class R4 $175 $ 544 $ 939 $2,045
Class R5 $150 $ 465 $ 804 $1,762
</Table>

(a) Includes a 5.75% sales charge.
(b) Includes the applicable CDSC.
(c) Based on conversion of Class B shares to Class A shares in the ninth year of
ownership.

You would pay the following expenses if you did not redeem your shares:

<Table>
<Caption>
1 YEAR 3 YEARS 5 YEARS 10 YEARS

Class A(a) $754 $1,129 $1,529 $2,644
Class B $265 $ 815 $1,391 $2,775(b)
Class C $266 $ 818 $1,396 $2,967
Class I $145 $ 450 $ 777 $1,707
Class R4 $175 $ 544 $ 939 $2,045
Class R5 $150 $ 465 $ 804 $1,762
</Table>

(a) Includes a 5.75% sales charge.
(b) Based on conversion of Class B shares to Class A shares in the ninth year of
ownership.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 13P

OTHER INVESTMENT STRATEGIES AND RISKS

Other Investment Strategies. In addition to the principal investment strategies
previously described, the Fund may utilize investment strategies that are not
principal investment strategies, including investment in affiliated and non-
affiliated pooled investment vehicles (including mutual funds and exchange
traded funds (ETFs), also referred to as "acquired funds") ownership of which
results in the Fund bearing its proportionate share of the acquired funds' fees
and expenses. Although ETFs are designed to replicate the price and yield of a
specified market index, there is no guarantee that an ETF will track its
specified market index, which may result in a loss. For more information on
strategies and holdings, and the risks of such strategies, including derivative
instruments that the Fund may use, see the Fund's SAI and its annual and
semiannual reports.

Unusual Market Conditions. During unusual market conditions, the Fund may
temporarily invest more of its assets in money market securities than during
normal market conditions. Although investing in these securities would serve
primarily to attempt to avoid losses, this type of investing also could prevent
the Fund from achieving its investment objective. During these times, the
portfolio managers may make frequent securities trades that could result in
increased fees, expenses and taxes, and decreased performance. Instead of
investing in money market securities directly, the Fund may invest in shares of
an affiliated money market fund. See "Cash Reserves" under the section "General
Information" for more information.

Securities Transaction Commissions. Securities transactions involve the payment
by the Fund of brokerage commissions to broker-dealers, on occasion as
compensation for research or brokerage services (commonly referred to as "soft
dollars"), as the portfolio managers buy and sell securities for the Fund in
pursuit of its objective. A description of the policies governing the Fund's
securities transactions and the dollar value of brokerage commissions paid by
the Fund are set forth in the SAI. The brokerage commissions set forth in the
SAI do not include implied commissions or mark-ups (implied commissions) paid by
the Fund for principal transactions (transactions made directly with a dealer or
other counterparty), including most fixed income securities (and certain other
instruments, including derivatives). Brokerage commissions do not reflect other
elements of transaction costs, including the extent to which the Fund's purchase
and sale transactions may cause the market to move and change the market price
for an investment.

Although brokerage commissions and implied commissions are not reflected in the
expense table under "Fees and Expenses," they are reflected in the total return
of the Fund.

- --------------------------------------------------------------------------------
14P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

Portfolio Turnover. Trading of securities may produce capital gains, which are
taxable to shareholders when distributed. Active trading may also increase the
amount of brokerage commissions paid or mark-ups to broker-dealers that the Fund
pays when it buys and sells securities. Capital gains and increased brokerage
commissions or mark-ups paid to broker-dealers may adversely affect a fund's
performance. The Fund's historical portfolio turnover rate, which measures how
frequently the Fund buys and sells investments, is shown in the "Financial
Highlights."

Directed Brokerage. The Fund's Board of Directors (Board) has adopted a policy
prohibiting the investment manager, or any subadviser, from considering sales of
shares of the Fund as a factor in the selection of broker-dealers through which
to execute securities transactions.

Additional information regarding securities transactions can be found in the
SAI.

FUND MANAGEMENT AND COMPENSATION

INVESTMENT MANAGER

RiverSource Investments, LLC (the investment manager or RiverSource
Investments), 200 Ameriprise Financial Center, Minneapolis, Minnesota 55474, is
the investment manager to the RiverSource funds (including the RiverSource
Partners funds, Threadneedle funds, and Seligman funds), and is a wholly-owned
subsidiary of Ameriprise Financial, Inc. (Ameriprise Financial). Ameriprise
Financial is a financial planning and financial services company that has been
offering solutions for clients' asset accumulation, income management and
protection needs for more than 110 years. In addition to managing investments
for all of the RiverSource funds, RiverSource Investments manages investments
for itself and its affiliates. For institutional clients, RiverSource
Investments and its affiliates provide investment management and related
services, such as separate account asset management, and institutional trust and
custody, as well as other investment products. For all of its clients,
RiverSource Investments seeks to allocate investment opportunities in an
equitable manner over time. See the SAI for more information.

The Fund pays RiverSource Investments a fee for managing its assets. Under the
Investment Management Services Agreement (Agreement), the fee for the most
recent fiscal year was 1.16% of the Fund's average daily net assets, including
an adjustment under the terms of a performance incentive arrangement. The
adjustment is computed by comparing the Fund's performance to the performance of
an index of comparable funds published by Lipper Inc. The index against which
the Fund's performance is currently measured for purposes of the performance
incentive adjustment is the Lipper Emerging Markets Funds Index. In certain
circumstances, the Fund's Board may approve a change in the index. The maximum
adjustment (increase or decrease) is 0.12% of the Fund's average net assets on
an annual basis. Under the Agreement, the Fund also pays taxes,

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 15P

brokerage commissions, and nonadvisory expenses. A discussion regarding the
basis for the Board approving the Agreement is available in the Fund's most
recent annual or semiannual shareholder report.

RiverSource Investments contracts with and compensates Threadneedle
International Limited (Subadviser or Threadneedle) to manage the investment of
the Fund's assets. RiverSource Investments monitors the compliance of
Threadneedle with the investment objectives and related policies of the Fund,
reviews the performance of Threadneedle, and reports periodically to the Board.

Threadneedle manages the Fund's assets based upon its experience managing funds
with investment goals and strategies substantially similar to those of the Fund.

THREADNEEDLE

Threadneedle, located at 60 St. Mary Axe, London EC3A 8JQ, England, is an
affiliate of RiverSource Investments, and an indirect wholly-owned subsidiary of
Ameriprise Financial, Inc. The portfolio managers who lead the team responsible
for the day-to-day management of the Fund are:

Julian A.S. Thompson, Portfolio Manager

- - Managed the Fund since 2000.

- - Joined Threadneedle in 2003.

- - Began investment career in 1993 as an Investment Manager for Stewart Ivory, a
Scottish investment company, 1993 to 1999. Portfolio Manager, American Express
Asset Management International, 1999 to 2003.

- - BA and Ph.D., Magdalene College, Cambridge University.

Jules Mort, Deputy Portfolio Manager

- - Deputy managed the Fund since 2003.

- - Joined Threadneedle in 2001 as a fund manager.

- - Began investment career in 1997 as an Analyst and Portfolio Manager, Baillie
Gifford & Co., 1997 to 2001.

- - BA (Hons), Oxford University 1996.

The SAI provides additional information about portfolio manager compensation,
management of other accounts and ownership of shares in the Fund.

- --------------------------------------------------------------------------------
16P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

FINANCIAL HIGHLIGHTS

THE FINANCIAL HIGHLIGHTS TABLES ARE INTENDED TO HELP YOU UNDERSTAND THE FUND'S
FINANCIAL PERFORMANCE. CERTAIN INFORMATION REFLECTS FINANCIAL RESULTS FOR A
SINGLE FUND SHARE. THE TOTAL RETURNS IN THE TABLES REPRESENT THE RATE THAT AN
INVESTOR WOULD HAVE EARNED OR LOST ON AN INVESTMENT IN THE FUND (ASSUMING
REINVESTMENT OF ALL DIVIDENDS AND DISTRIBUTIONS). THE INFORMATION FOR THE FISCAL
YEARS ENDED ON OR AFTER OCT. 31, 2007 HAS BEEN DERIVED FROM THE FINANCIAL
STATEMENTS AUDITED BY ERNST & YOUNG LLP, WHOSE REPORT, ALONG WITH THE FUND'S
FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS, IS INCLUDED IN THE ANNUAL REPORT
WHICH, IF NOT INCLUDED WITH THIS PROSPECTUS, IS AVAILABLE UPON REQUEST. THE
INFORMATION FOR THE PERIODS ENDED ON OR BEFORE OCT. 31, 2006 HAS BEEN AUDITED BY
OTHER AUDITORS.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 17P

CLASS A

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008 2007 2006 2005 2004

Net asset value, beginning of period $14.99 $11.32 $8.23 $6.27 $5.46
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) .08(b) .04(b) .01 .04 .03
Net gains (losses) (both realized and
unrealized) (7.24) 6.27 3.10 1.95 .84
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (7.16) 6.31 3.11 1.99 .87
- --------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
Dividends from net investment income (.18) -- (.02) (.03) (.06)
Distributions from realized gains (2.69) (2.64) -- -- --
- --------------------------------------------------------------------------------------------------------------
Total distributions (2.87) (2.64) (.02) (.03) (.06)
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $4.96 $14.99 $11.32 $8.23 $6.27
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $250 $661 $425 $295 $191
- --------------------------------------------------------------------------------------------------------------
Gross expenses prior to expense
waiver/reimbursement(c),(d) 1.87% 1.83% 1.81% 1.79% 1.83%
- --------------------------------------------------------------------------------------------------------------
Net expenses after expense
waiver/reimbursement(d),(e),(f) 1.87% 1.83% 1.81% 1.79% 1.83%
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) .78% .31% .19% .54% .41%
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133% 125% 145% 124% 128%
- --------------------------------------------------------------------------------------------------------------
Total return(g) (57.79%) 68.21% 37.85% 31.83% 16.09%
- --------------------------------------------------------------------------------------------------------------
</Table>

(a) For a share outstanding throughout the period. Rounded to the nearest cent.
(b) Per share amounts have been calculated using the average shares outstanding
method.
(c) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances.
(d) In addition to the fees and expenses which the Fund bears directly, the Fund
indirectly bears a pro rata share of the fees and expenses of the acquired
funds in which it invests. Such indirect expenses are not included in the
above reported expense ratios.
(e) The Investment Manager and its affiliates have agreed to waive/reimburse
certain fees and expenses (excluding fees and expenses of acquired funds),
before giving effect to any performance incentive adjustment.
(f) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances. Earnings and bank fee credits for the year ended Oct. 31, 2008
were less than 0.01% of average net assets.
(g) Total return does not reflect payment of a sales charge.

- --------------------------------------------------------------------------------
18P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

CLASS B

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008 2007 2006 2005 2004

Net asset value, beginning of period $13.73 $10.63 $7.77 $5.95 $5.19
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) .00(b),(c) (.05)(b) (.05) (.01) (.02)
Net gains (losses) (both realized and
unrealized) (6.53) 5.79 2.91 1.83 .81
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (6.53) 5.74 2.86 1.82 .79
- --------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
Dividends from net investment income (.08) -- -- -- (.03)
Distributions from realized gains (2.69) (2.64) -- -- --
- --------------------------------------------------------------------------------------------------------------
Total distributions (2.77) (2.64) -- -- (.03)
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $4.43 $13.73 $10.63 $7.77 $5.95
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $28 $94 $77 $74 $73
- --------------------------------------------------------------------------------------------------------------
Gross expenses prior to expense
waiver/reimbursement(d),(e) 2.62% 2.58% 2.57% 2.55% 2.59%
- --------------------------------------------------------------------------------------------------------------
Net expenses after expense
waiver/reimbursement(e),(f),(g) 2.62% 2.58% 2.57% 2.55% 2.59%
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) .02% (.48%) (.55%) (.24%) (.32%)
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133% 125% 145% 124% 128%
- --------------------------------------------------------------------------------------------------------------
Total return(h) (58.08%) 66.95% 36.81% 30.59% 15.18%
- --------------------------------------------------------------------------------------------------------------
</Table>

(a) For a share outstanding throughout the period. Rounded to the nearest cent.
(b) Per share amounts have been calculated using the average shares outstanding
method.
(c) Rounds to zero.
(d) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances.
(e) In addition to the fees and expenses which the Fund bears directly, the Fund
indirectly bears a pro rata share of the fees and expenses of the acquired
funds in which it invests. Such indirect expenses are not included in the
above reported expense ratios.
(f) The Investment Manager and its affiliates have agreed to waive/reimburse
certain fees and expenses (excluding fees and expenses of acquired funds),
before giving effect to any performance incentive adjustment.
(g) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances. Earnings and bank fee credits for the year ended Oct. 31, 2008
were less than 0.01% of average net assets.
(h) Total return does not reflect payment of a sales charge.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 19P

CLASS C

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008 2007 2006 2005 2004

Net asset value, beginning of period $13.78 $10.66 $7.79 $5.97 $5.20
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) .00(b),(c) (.05)(b) (.06) -- (.01)
Net gains (losses) (both realized and
unrealized) (6.54) 5.81 2.93 1.82 .81
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (6.54) 5.76 2.87 1.82 .80
- --------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
Dividends from net investment income (.11) -- -- -- (.03)
Distributions from realized gains (2.69) (2.64) -- -- --
- --------------------------------------------------------------------------------------------------------------
Total distributions (2.80) (2.64) -- -- (.03)
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $4.44 $13.78 $10.66 $7.79 $5.97
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $3 $8 $5 $3 $1
- --------------------------------------------------------------------------------------------------------------
Gross expenses prior to expense
waiver/reimbursement(d),(e) 2.63% 2.59% 2.58% 2.56% 2.60%
- --------------------------------------------------------------------------------------------------------------
Net expenses after expense
waiver/reimbursement(e),(f),(g) 2.63% 2.59% 2.58% 2.56% 2.60%
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) .03% (.48%) (.57%) (.19%) (.34%)
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133% 125% 145% 124% 128%
- --------------------------------------------------------------------------------------------------------------
Total return(h) (58.15%) 67.03% 36.84% 30.54% 15.37%
- --------------------------------------------------------------------------------------------------------------
</Table>

- --------------------------------------------------------------------------------
20P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

CLASS I

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008 2007 2006 2005 2004(b)

Net asset value, beginning of period $15.38 $11.50 $8.35 $6.36 $6.54
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) .11(c) .09(c) .03 .06 .01
Net gains (losses) (both realized and
unrealized) (7.45) 6.43 3.16 1.98 (.19)
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (7.34) 6.52 3.19 2.04 (.18)
- --------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
Dividends from net investment income (.23) -- (.04) (.05) --
Distributions from realized gains (2.69) (2.64) -- -- --
- --------------------------------------------------------------------------------------------------------------
Total distributions (2.92) (2.64) (.04) (.05) --
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $5.12 $15.38 $11.50 $8.35 $6.36
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $-- $56 $41 $19 $13
- --------------------------------------------------------------------------------------------------------------
Gross expenses prior to expense
waiver/reimbursement(d),(e) 1.42% 1.39% 1.35% 1.30% 1.35%(f)
- --------------------------------------------------------------------------------------------------------------
Net expenses after expense
waiver/reimbursement(e),(g),(h) 1.42% 1.39% 1.35% 1.30% 1.35%(f)
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) .97% .75% .63% .97% .79%(f)
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133% 125% 145% 124% 128%
- --------------------------------------------------------------------------------------------------------------
Total return (57.63%) 69.07% 38.36% 32.32% (2.75%)(i)
- --------------------------------------------------------------------------------------------------------------
</Table>

(a) For a share outstanding throughout the period. Rounded to the nearest cent.
(b) For the period from March 4, 2004 (inception date) to Oct. 31, 2004.
(c) Per share amounts have been calculated using the average shares outstanding
method.
(d) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances.
(e) In addition to the fees and expenses which the Fund bears directly, the Fund
indirectly bears a pro rata share of the fees and expenses of the acquired
funds in which it invests. Such indirect expenses are not included in the
above reported expense ratios.
(f) Adjusted to an annual basis.
(g) The Investment Manager and its affiliates have agreed to waive/reimburse
certain fees and expenses (excluding fees and expenses of acquired funds),
before giving effect to any performance incentive adjustment.
(h) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances. Earnings and bank fee credits for the year ended Oct. 31, 2008
were less than 0.01% of average net assets.
(i) Not annualized.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 21P

CLASS R4

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008 2007 2006 2005 2004

Net asset value, beginning of period $15.32 $11.50 $8.33 $6.35 $5.52
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss) .11(b) .05(b) .03 .05 .04
Net gains (losses) (both realized and
unrealized) (7.45) 6.41 3.14 1.97 .86
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (7.34) 6.46 3.17 2.02 .90
- --------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS:
Dividends from net investment income (.15) -- -- (.04) (.07)
Distributions from realized gains (2.69) (2.64) -- -- --
- --------------------------------------------------------------------------------------------------------------
Total distributions (2.84) (2.64) -- (.04) (.07)
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $5.14 $15.32 $11.50 $8.33 $6.35
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $1 $2 $6 $2 $18
- --------------------------------------------------------------------------------------------------------------
Gross expenses prior to expense
waiver/reimbursement(c),(d) 1.73% 1.65% 1.63% 1.59% 1.65%
- --------------------------------------------------------------------------------------------------------------
Net expenses after expense
waiver/reimbursement(d),(e),(f) 1.47% 1.65% 1.63% 1.59% 1.65%
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) 1.12% .45% .41% .81% .61%
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133% 125% 145% 124% 128%
- --------------------------------------------------------------------------------------------------------------
Total return (57.58%) 68.51% 38.06% 31.87% 16.50%
- --------------------------------------------------------------------------------------------------------------
</Table>

- --------------------------------------------------------------------------------
22P THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS

CLASS R5

<Table>
<Caption>
PER SHARE INCOME AND CAPITAL CHANGES(a)
Fiscal period ended Oct. 31, 2008(b)

Net asset value, beginning of period $9.32
- --------------------------------------------------------------------------------------------------------------
INCOME FROM INVESTMENT OPERATIONS:
Net investment income (loss)(c) .03
Net gains (losses) (both realized and
unrealized) (4.22)
- --------------------------------------------------------------------------------------------------------------
Total from investment operations (4.19)
- --------------------------------------------------------------------------------------------------------------
Net asset value, end of period $5.13
- --------------------------------------------------------------------------------------------------------------

RATIOS TO AVERAGE NET ASSETS/SUPPLEMENTAL DATA

Net assets, end of period (in millions) $--
- --------------------------------------------------------------------------------------------------------------
Total expenses(d),(e),(f) 1.47%(g)
- --------------------------------------------------------------------------------------------------------------
Net investment income (loss) 1.57%(g)
- --------------------------------------------------------------------------------------------------------------
Portfolio turnover rate 133%
- --------------------------------------------------------------------------------------------------------------
Total return (44.96%)(h)
- --------------------------------------------------------------------------------------------------------------
</Table>

(a) For a share outstanding throughout the period. Rounded to the nearest cent.
(b) For the period from Aug. 1, 2008 (when shares became publicly available) to
Oct. 31, 2008.
(c) Per share amount has been calculated using the average shares outstanding
method.
(d) In addition to the fees and expenses which the Fund bears directly, the Fund
indirectly bears a pro rata share of the fees and expenses of the acquired
funds in which it invests. Such indirect expenses are not included in the
above reported expense ratios.
(e) The Investment Manager and its affiliates have agreed to waive/reimburse
certain fees and expenses (excluding fees and expenses of acquired funds),
before giving effect to any performance incentive adjustment.
(f) Includes the impact of a performance incentive adjustment, if any. Expense
ratio is before reduction for earnings and bank fee credits on cash
balances. Earnings and bank fee credits for the year ended Oct. 31, 2008
were less than 0.01% of average net assets.
(g) Adjusted to an annual basis.
(h) Not annualized.

- --------------------------------------------------------------------------------
THREADNEEDLE EMERGING MARKETS FUND -- 2008 PROSPECTUS 23P

RIVERSOURCE COMPLEX OF FUNDS

THE RIVERSOURCE COMPLEX OF FUNDS INCLUDES "RIVERSOURCE" FUNDS, "RIVERSOURCE
PARTNERS" FUNDS, AND "THREADNEEDLE" FUNDS (EACH INDIVIDUALLY A "FUND" OR A
"RIVERSOURCE FUND" AND COLLECTIVELY THE "FUNDS" OR THE "RIVERSOURCE FUNDS"). THE
RIVERSOURCE COMPLEX OF FUNDS ALSO INCLUDES "SELIGMAN" FUNDS. THE RIVERSOURCE
FUNDS AND THE SELIGMAN FUNDS SHARE THE SAME BOARD OF DIRECTORS/TRUSTEES (THE
"BOARD"), BUT INVESTORS MAY NOT CURRENTLY MAKE EXCHANGES BETWEEN THE SELIGMAN
FUNDS AND THE RIVERSOURCE FUNDS. SELIGMAN FUNDS GENERALLY HAVE SEPARATE AND
DISTINCT POLICIES AND PROCEDURES FROM THE RIVERSOURCE FUNDS. THE RIVERSOURCE
FUNDS SHARE THE SAME POLICIES AND PROCEDURES INCLUDING THOSE SET FORTH IN THIS
SERVICE SECTION OF THIS PROSPECTUS. FOR EXAMPLE, FOR PURPOSES OF CALCULATING THE
INITIAL SALES CHARGE ON THE PURCHASE OF CLASS A SHARES OF A RIVERSOURCE FUND, AN
INVESTOR OR FINANCIAL ADVISOR SHOULD CONSIDER THE COMBINED MARKET VALUE OF ALL
RIVERSOURCE FUNDS (INCLUDING "THREADNEEDLE" OR "RIVERSOURCE PARTNERS" FUNDS),
OWNED BY THE INVESTOR AS DEFINED UNDER "INITIAL SALES CHARGE -- RIGHTS OF
ACCUMULATION (ROA)." AN INVESTOR OR FINANCIAL ADVISOR MAY NOT INCLUDE THE MARKET
VALUE OF ANY SELIGMAN FUNDS OWNED BY THE INVESTOR IN THIS CALCULATION.

BUYING AND SELLING SHARES

The RiverSource funds are generally available directly and through broker-
dealers, banks, and other financial intermediaries or institutions (financial
institutions), including certain qualified and non-qualified plans, wrap fee
products or other investment products sponsored by financial institutions. THESE
FINANCIAL INSTITUTIONS MAY CHARGE YOU ADDITIONAL FEES FOR THE SERVICES THEY
PROVIDE AND THEY MAY HAVE DIFFERENT POLICIES NOT DESCRIBED IN THIS PROSPECTUS.
Some policy differences may include different minimum investment amounts,
exchange privileges, fund choices and cutoff times for investments.
Additionally, recordkeeping, transaction processing and payments of
distributions relating to your account may be performed by the financial
institutions through which your shares of the fund(s) are held. Since the fund
(and its service providers) may not have a record of your account transactions,
you should always contact the financial institution through which you purchased
or at which you maintain your shares of the fund to make changes to your account
or to give instructions concerning your account, or to obtain information about
your account. The fund and its service providers, including the distributor and
the transfer agent, are not responsible for the failure of one of these
financial institutions to carry out its obligations to its customers.

- --------------------------------------------------------------------------------
S.1

S-6400-4

DESCRIPTION OF SHARE CLASSES

INVESTMENT OPTIONS -- CLASSES OF SHARES

The RiverSource funds offer different classes of shares. There are differences
among the fees and expenses for each share class. See the "Fees and Expenses"
table for more information. Not everyone is eligible to buy every share class.
After determining which share classes you are eligible to buy, decide which
share class best suits your needs. Your financial institution can help you with
this decision. The following table shows the key features of each share class.
(THE COVER OF THIS PROSPECTUS INDICATES WHICH SHARE CLASSES ARE CURRENTLY
OFFERED FOR THIS FUND.)

INVESTMENT OPTIONS SUMMARY

<Table>
<Caption>
Contingent Plan
Initial Deferred Sales Distribution and Administration
AVAILABILITY(a) Sales Charge Charge (CDSC) Service Fee(b) Fee
- --------------------------------------------------------------------------------------------------------------------------------

Class A Available to Yes. Payable at No.(c) Yes. No.
all investors. time of purchase. 0.25%
Lower or no sales
charge for larger
investments.
- --------------------------------------------------------------------------------------------------------------------------------

Class B(d) Available to No. Entire Maximum 5% CDSC Yes. No.
all investors. purchase price is during the first 1.00%
invested in shares year decreasing to
of the fund. 0% after six
years.
- --------------------------------------------------------------------------------------------------------------------------------

Class C Available to No. Entire 1% CDSC may apply Yes. No.
all investors. purchase price is if you sell shares 1.00%
invested in shares within one year
of the fund. after purchase.
- --------------------------------------------------------------------------------------------------------------------------------

Class I Limited to No. No. No. No.
qualifying
institutional
investors.
- --------------------------------------------------------------------------------------------------------------------------------

Class R2 Limited to No. No. Yes. Yes.
qualifying 0.50% 0.25%
institutional
investors.
- --------------------------------------------------------------------------------------------------------------------------------

Class R3 Limited to No. No. Yes. Yes.
qualifying 0.25% 0.25%
institutional
investors.
- --------------------------------------------------------------------------------------------------------------------------------

Class R4 Limited to No. No. No. Yes.
qualifying 0.25%
institutional
investors.
- --------------------------------------------------------------------------------------------------------------------------------

Class R5 Limited to No. No. No. No.
qualifying
institutional
investors.
- --------------------------------------------------------------------------------------------------------------------------------

</Table>

- --------------------------------------------------------------------------------
S.2

INVESTMENT OPTIONS SUMMARY (CONTINUED)

Class W Limited to No. No. Yes. No.
qualifying 0.25%
discretionary
managed accounts.
- --------------------------------------------------------------------------------------------------------------------------------

</Table>

(a) See "Buying and Selling Shares, Determining which class of shares to
purchase" for more information on availability of share classes and eligible
investors. See "Buying and Selling Shares, Opening an Account" for
information on minimum investment and account balance requirements.
(b) For each of Class A, Class B, Class C, Class R2, Class R3 and Class W
shares, as applicable, each fund has adopted a plan under Rule 12b-1 of the
Investment Company Act of 1940, as amended, that allows it to pay
distribution and shareholder servicing-related expenses for the sale of
shares and the servicing of shareholders. This plan has been reviewed and
approved by the Board. Because these fees are paid out of fund assets on an
on-going basis, over time these fees will increase the cost of your
investment and may cost you more than paying other types of distribution
(sales) or servicing charges.
(c) A 1% CDSC may be assessed on Class A shares sold within 18 months after
purchase. See "Buying and Selling Shares, Sales Charges, Class
A -- contingent deferred sales charge" for more information.
(d) See "Buying and Selling Shares, Sales Charges, Class B and Class
C -- contingent deferred sales charge alternative" for more information on
the timing of conversion of Class B shares to Class A shares. Timing of
conversion will vary depending on the date of your original purchase of the
Class B shares.

DISTRIBUTION AND SERVICE FEES

The distribution and shareholder servicing fees for Class A, Class B, Class C,
Class R2, Class R3 and Class W shares are subject to the requirements of Rule
12b-1 under the Investment Company Act of 1940, as amended, and are used to
reimburse the distributor for certain expenses it incurs in connection with
distributing a fund's shares and directly or indirectly providing services to
fund shareholders. These expenses include payment of distribution and
shareholder servicing fees to financial institutions that sell shares of the
fund or provide services to fund shareholders, up to 0.50% of the average daily
net assets of Class R2 shares sold and held through them and up to 0.25% of the
average daily net assets of Class A, Class B, Class C, Class R3 and Class W
shares sold and held through them. For Class A, Class B, Class R2, Class R3 and
Class W shares, the distributor begins to pay these fees immediately after
purchase. For Class C shares, the distributor pays these fees in advance for the
first 12 months. Financial institutions also receive distribution fees up to
0.75% of the average daily net assets of Class C shares sold and held through
them, which the distributor begins to pay 12 months after purchase. For Class B
shares, and, for the first 12 months following the sale of Class C shares, the
fund's distributor retains the distribution fee of up to 0.75% in order to
finance the payment of sales commissions to financial institutions that sell
Class B shares, and to pay for other distribution related expenses. Financial
institutions may compensate their financial advisors with the shareholder
servicing and distribution fees paid to them by the distributor. IF YOU MAINTAIN
SHARES OF THE FUND DIRECTLY WITH THE FUND, WITHOUT WORKING DIRECTLY WITH A
FINANCIAL INSTITUTION OR FINANCIAL ADVISOR, DISTRIBUTION AND SERVICE FEES WILL
BE RETAINED BY THE DISTRIBUTOR.

- --------------------------------------------------------------------------------
S.3

PLAN ADMINISTRATION FEE

Class R2, Class R3 and Class R4 shares pay an annual plan administration
services fee for the provision of various administrative, recordkeeping,
communication and educational services. The fee for Class R2, Class R3 and Class
R4 shares is equal on an annual basis to 0.25% of average daily net assets
attributable to the respective class.

DETERMINING WHICH CLASS OF SHARES TO PURCHASE

CLASS A, CLASS B AND CLASS C SHARES

New purchases of Class B shares will not be permitted if your Rights of
Accumulation are $50,000 or higher, and new purchases of Class C shares will not
be permitted if your Rights of Accumulation are $1,000,000 or higher. See "Sales
Charges, Initial Sales Charge -- Rights of Accumulation (ROA)" for information
on Rights of Accumulation.

Class B shares have a higher annual distribution fee than Class A shares and a
contingent deferred sales charge (CDSC) for six years. Class B shares convert to
Class A shares in the ninth year of ownership. Class B shares purchased through
reinvested dividends and distributions also will convert to Class A shares in
the same proportion as the other Class B shares.

Class C shares also have a higher annual distribution fee than Class A shares.
Class C shares have no sales charge if you hold the shares for longer than one
year. Unlike Class B shares, Class C shares do not convert to Class A shares. As
a result, you will pay a distribution fee for as long as you hold Class C
shares. If you choose a deferred sales charge option (Class B or Class C), you
should consider the length of time you intend to hold your shares. To help you
determine which investment is best for you, consult your financial institution.

CLASS I SHARES.

The following eligible investors may purchase Class I shares:

- - Any fund distributed by RiverSource Distributors, Inc., if the fund seeks to
achieve its investment objective by investing primarily in shares of the fund
and other RiverSource funds.

Class I shares may be purchased, sold or exchanged only through the distributor
or an authorized financial institution.

CLASS R SHARES.

The following eligible institutional investors may purchase Class R2, Class R3,
Class R4 and Class R5 shares:

- - Qualified employee benefit plans.

- - Trust companies or similar institutions, and charitable organizations that
meet the definition in Section 501(c)(3) of the Internal Revenue Code.

- --------------------------------------------------------------------------------
S.4

- - Non-qualified deferred compensation plans whose participants are included in a
qualified employee benefit plan described above.

- - State sponsored college savings plans established under Section 529 of the
Internal Revenue Code.

- - Health Savings Accounts (HSAs) created pursuant to public law 108-173.

Additionally, if approved by the distributor, the following eligible
institutional investors may purchase Class R5 shares:

- - Institutional or corporate accounts above a threshold established by the
distributor (currently $1 million per fund or $10 million in all RiverSource
funds).

- - Bank Trust departments.

Class R shares generally are not available to retail non-retirement accounts,
traditional and Roth IRAs, Coverdell Educational Savings Accounts, SEPs, SAR-
SEPs, SIMPLE IRAs and individual 403(b) plans.

Class R shares may be purchased, sold or exchanged only through the distributor
or an authorized financial institution.

CLASS W SHARES.

The following eligible investors may purchase Class W shares:

- - Investors purchasing through authorized investment programs managed by
investment professionals, including discretionary managed account programs.

Class W shares may be purchased, sold or exchanged only through the distributor
or an authorized financial institution.

Shares originally purchased in a discretionary managed account may continue to
be held in Class W outside of a discretionary managed account, but no additional
Class W purchases may be made and no exchanges to Class W shares of another fund
may be made outside of a discretionary managed account.

IN ADDITION, FOR CLASS I, CLASS R AND CLASS W SHARES, THE DISTRIBUTOR, IN ITS
SOLE DISCRETION, MAY ACCEPT OR AUTHORIZE FINANCIAL INSTITUTIONS TO ACCEPT
INVESTMENTS FROM OTHER PURCHASERS NOT LISTED ABOVE.

For more information, see the SAI.

SALES CHARGES

CLASS A -- INITIAL SALES CHARGE ALTERNATIVE

Your purchase price for Class A shares is generally the net asset value (NAV)
plus a front-end sales charge. The distributor receives the sales charge and re-
allows a portion of the sales charge to the financial institution through which
you purchased the shares. The distributor retains the balance of the sales
charge. The distributor retains the full sales charge you pay when you purchase
shares of the fund directly (not through a separately authorized financial
institution). Sales charges vary depending on the amount of your purchase.

- --------------------------------------------------------------------------------
S.5

SALES CHARGE* FOR CLASS A SHARES:

<Table>
<Caption>
MAXIMUM RE-ALLOWANCE
AS A % OF AS A % OF AS A % OF
TOTAL MARKET VALUE PURCHASE PRICE** NET AMOUNT INVESTED PURCHASE PRICE
- ----------------------------------------------------------------------------------

Up to $49,999 5.75% 6.10% 5.00%
$50,000 -- $99,999 4.75 4.99 4.00
$100,000 -- $249,999 3.50 3.63 3.00
$250,000 -- $499,999 2.50 2.56 2.15
$500,000 -- $999,999 2.00 2.04 1.75
$1,000,000 or more 0.00 0.00 0.00***
</Table>

*Because of rounding in the calculation of the offering price, the portion
of the sales charge retained by the distributor may vary and the actual
sales charge you pay may be more or less than the sales charge calculated
using these percentages.
**Purchase price includes the sales charge.
***Although there is no sales charge for purchases with a total market value
over $1,000,000, and therefore no re-allowance, the distributor may pay a
financial institution the following: a sales commission of up to 1.00% for
a sale with a total market value of $1,000,000 to $2,999,999; a sales
commission up to 0.50% for a sale of $3,000,000 to $9,999,999; and a sales
commission up to 0.25% for a sale of $10,000,000 or more.

INITIAL SALES CHARGE -- RIGHTS OF ACCUMULATION (ROA). You may be able to reduce
the sales charge on Class A shares, based on the combined market value of
accounts in your ROA group, as described below. The current market values of the
following investments are eligible to be added together for purposes of
determining the sales charge on your purchase:

- - Your current investment in a fund; and

- - Previous investments you and members of your household have made in Class A,
Class B or Class C shares in the fund and other RiverSource funds, provided
your investment was subject to a sales charge. Your household consists of you,
your spouse or domestic partner and your unmarried children under age 21
sharing a mailing address.

The following accounts are eligible to be included in determining the sales
charge on your purchase:

- - Individual or joint accounts;

- - Roth and traditional IRAs, SEPs, SIMPLEs and TSCAs, provided they are invested
in Class A, Class B or Class C shares that were subject to a sales charge;

- - UGMA/UTMA accounts for which you, your spouse, or your domestic partner is
parent or guardian of the minor child;

- - Revocable trust accounts for which you or a member of your household,
individually, is the beneficial owner/grantor;

- - Accounts held in the name of your, your spouse's, or your domestic partner's
sole proprietorship or single owner limited liability company or S
corporation; and

- --------------------------------------------------------------------------------
S.6

- - Qualified retirement plan assets, provided that you are the sole owner of the
business sponsoring the plan, are the sole participant (other than a spouse)
in the plan, and have no intention of adding participants to the plan.

The following accounts are NOT eligible to be included in determining the sales
charge on your purchase:

- - Accounts of pension and retirement plans with multiple participants, such as
401(k) plans (which are combined to reduce the sales charge for the entire
pension or retirement plan and therefore are not used to reduce the sales
charge for your individual accounts);

- - Investments in Class A shares where the sales charge is waived, for example,
purchases through wrap accounts;

- - Investments in Class D, Class E, Class I, Class R2, Class R3, Class R4, Class
R5, Class W or Class Y shares;

- - Investments in 529 plans, donor advised funds, variable annuities, variable
life insurance products, wrap accounts or managed separate accounts; and

- - Charitable and irrevocable trust accounts.

If you purchase RiverSource fund shares through different financial
institutions, and you want to include those assets toward a reduced sales
charge, you must inform your financial institution in writing about the other
accounts when placing your purchase order. Contact your financial institution to
determine what information is required.

Unless you provide your financial institution in writing with information about
all of the accounts that may count toward a sales charge reduction, there can be
no assurance that you will receive all of the reductions for which you may be
eligible. You should request that your financial institution provide this
information to the fund when placing your purchase order.

For more information on rights of accumulation, please see the SAI.

INITIAL SALES CHARGE -- LETTER OF INTENT (LOI). Generally, if you intend to
invest $50,000 or more (including any existing ROA) over a period of up to 13
months, you may be able to reduce the front-end sales charge(s) for investments
in Class A shares by completing and filing an LOI. The required form of LOI may
vary by financial institution. Existing ROA can be included in your LOI. Each
purchase of fund shares normally subject to an initial sales charge made during
the 13-month period will be made at the public offering price applicable to a
single transaction of the total dollar amount indicated by the LOI. Five percent
of the commitment amount will be placed in escrow. At the end of the 13-month
period, the LOI will end and the shares will be released from escrow. If you do
not invest the commitment amount by the end of the 13 months, the remaining
unpaid sales charge will be redeemed from the escrowed shares and the remaining
balance released from escrow.

- --------------------------------------------------------------------------------
S.7

Existing ROA Example. Shareholder currently has $60,000 ROA in RiverSource
funds. Shareholder completes an LOI to invest $100,000 in RiverSource funds (ROA
eligible accounts). Shareholder only needs to invest an additional $40,000 in
RiverSource funds' Class A shares in order to fulfill the LOI commitment and
receive reduced front-end sales charge(s) over the next 13 months.

Notification Obligation. You must request the reduced sales charge when you buy
shares. If you do not complete and file an LOI, or do not request the reduced
sales charge at the time of purchase, you will not be eligible for the reduced
sales charge. You should request that your financial institution provide this
information to the fund when placing your purchase order. For more detail on
LOIs, please contact your financial institution or see the SAI.

INITIAL SALES CHARGE -- WAIVERS OF THE SALES CHARGE FOR CLASS A SHARES. Sales
charges do not apply to:

- - current or retired Board members, officers or employees of RiverSource funds
or RiverSource Investments or its affiliates, their spouses or domestic
partners, children, parents and their spouse's or domestic partner's parents.

- - current or retired Ameriprise Financial Services, Inc. (Ameriprise Financial
Services) financial advisors, employees of financial advisors, their spouses
or domestic partners, children, parents and their spouse's or domestic
partner's parents.

- - registered representatives and other employees of financial institutions
having a selling agreement with the distributor, including their spouses,
domestic partners, children, parents and their spouse's or domestic partner's
parents.

- - portfolio managers employed by subadvisers of the RiverSource funds, including
their spouses or domestic partners, children, parents and their spouse's or
domestic partner's parents.

- - retirement plans qualified or created under sections 401(a), 401(k), 403(b) or
457 of the Internal Revenue Code, if those purchases are made through a
broker, agent, or other financial institution.

- - direct rollovers from qualified employee benefit plans, provided that the
rollover involves a transfer to Class A shares in the same fund.

- - purchases made:

- with dividend or capital gain distributions from a fund or from the same
class of another RiverSource fund;

- through or under a wrap fee product or other investment product sponsored by
a financial institution having a selling agreement with the distributor;

- through state sponsored college savings plans established under Section 529
of the Internal Revenue Code;

- through bank trust departments.

- - shareholders whose original purchase was in a Strategist fund merged into a
RiverSource fund in 2000.

- --------------------------------------------------------------------------------
S.8

Unless you provide your financial institution with information in writing about
all of the factors that may count toward a waiver of the sales charge, there can
be no assurance that you will receive all of the waivers for which you may be
eligible. You should request that your financial institution provide this
information to the fund when placing your purchase order.

Because the current prospectus is available on riversource.com free of charge,
RiverSource Investments does not separately disclose information regarding
breakpoint discounts on the website.

CLASS A -- CONTINGENT DEFERRED SALES CHARGE

For Class A shares purchased after Dec. 1, 2008 without a sales charge, a 1%
CDSC may be charged if you sell your shares within 18 months after purchase. A
CDSC will be based on the original purchase cost or the current market value of
the shares being sold, whichever is less.

CDSC -- WAIVERS OF THE CDSC FOR CLASS A SHARES. The CDSC will be waived on sales
of shares:

- - To which no sales commission or transaction fee was paid to an authorized
financial institution at the time of purchase.

- - Purchased through reinvestment of dividends and capital gain distributions.

- - In the event of the shareholder's death.

- - From a monthly, quarterly or annual systematic redemption plan of up to an
annual amount of 12% of the account value on a per fund basis.

- - In an account that has been closed because it falls below the minimum account
balance.

- - That result in mandatory withdrawals from an ERISA plan of a shareholder who
is at least 70 1/2 years old.

- - That result from returns of excess contributions or excess deferral amounts
made to a retirement plan participant.

- - Purchased prior to Dec. 1, 2008.

The distributor may, in its sole discretion, authorize the waiver of the CDSC
for additional purchases or categories of purchases. Policies relating to
waiving the CDSC may be modified or withdrawn at any time.

- --------------------------------------------------------------------------------
S.9

CLASS B AND CLASS C -- CONTINGENT DEFERRED SALES CHARGE ALTERNATIVE

FOR CLASS B, the CDSC is based on the sale amount and the number of years
between purchase and sale. The following table shows how CDSC percentages on
sales decline:

<Table>
<Caption>
IF THE SALE IS MADE DURING THE: THE CDSC PERCENTAGE RATE IS:*

First year 5%
Second year 4%
Third year 4%
Fourth year 3%
Fifth year 2%
Sixth year 1%
Seventh or eighth year 0%
</Table>

* Because of rounding in the calculation, the portion of the CDSC retained by
the distributor may vary and the actual CDSC you pay may be more or less
than the CDSC calculated using these percentages.

Although there is no front-end sales charge when you buy Class B shares, the
distributor pays a sales commission of 4% to financial institutions that sell
Class B shares. A portion of this commission may, in turn, be paid to your
financial advisor. The distributor receives any CDSC imposed when you sell your
Class B shares.

You may not make additional purchases of Class B shares if your ROA exceeds
$49,999.99.

Purchases made prior to May 21, 2005 age on a calendar year basis. Purchases
made beginning May 21, 2005 age on a daily basis. For example, a purchase made
on Nov. 12, 2004 completed its first year on Dec. 31, 2004 under calendar year
aging. However, a purchase made on Nov. 12, 2005 completed its first year on
Nov. 11, 2006 under daily aging.

Class B shares purchased prior to May 21, 2005 will convert to Class A shares in
the ninth calendar year of ownership. Class B shares purchased beginning May 21,
2005 will convert to Class A shares one month after the completion of the eighth
year of ownership.

FOR CLASS C, a 1% CDSC may be charged if you sell your shares within one year
after purchase. Although there is no front-end sales charge when you buy Class C
shares, the distributor pays a total amount up to 1% (including sales commission
and advance of service fees) to financial institutions that sell Class C shares.
See "Buying and Selling Shares -- Distribution and Service Fees." A portion of
this commission may, in turn, be paid to your financial advisor. The distributor
receives any CDSC imposed when you sell your Class C shares. You may not make
additional purchases of Class C shares if your ROA exceeds $999,999.99.

- --------------------------------------------------------------------------------
S.10

For both Class B and Class C, if the amount you sell causes the value of your
investment to fall below the cost of the shares you have purchased, the CDSC
will be based on the lower of the cost of those shares purchased or market
value. Because the CDSC is imposed only on sales that reduce your total purchase
payments, you do not have to pay a CDSC on any amount that represents
appreciation in the value of your shares, income earned by your shares, or
capital gains. In addition, the CDSC on your sale, if any, will be based on your
oldest purchase payment. The CDSC on the next amount sold will be based on the
next oldest purchase payment.

EXAMPLE

Assume you had invested $10,000 in Class B shares and that your investment had
appreciated in value to $12,000 after 3 1/2 years, including reinvested
dividends and capital gain distributions. You could sell up to $2,000 worth of
shares without paying a CDSC ($12,000 current value less $10,000 purchase
amount). If you sold $2,500 worth of shares, the CDSC would apply to the $500
representing part of your original purchase price. The CDSC rate would be 3%
because the sale was made during the fourth year after the purchase.

CDSC -- WAIVERS OF THE CDSC FOR CLASS B SHARES. The CDSC will be waived on sales
of shares:

- - in the event of the shareholder's death;

- - held in trust for an employee benefit plan; or

- - held in IRAs or certain qualified plans, such as Keogh plans, tax-sheltered
custodial accounts or corporate pension plans, provided that the shareholder
is:

- at least 59 1/2 years old AND

- taking a retirement distribution (if the sale is part of a transfer to an
IRA or qualified plan, or a custodian-to-custodian transfer, the CDSC will
not be waived) OR

- selling under an approved substantially equal periodic payment arrangement.

CDSC -- WAIVERS OF THE CDSC FOR CLASS C SHARES. The CDSC will be waived on sales
of shares in the event of the shareholder's death.

CLASS I, CLASS R2, CLASS R3, CLASS R4, CLASS R5 AND CLASS W -- NO SALES CHARGE.
For each of Class I, Class R2, Class R3, Class R4, Class R5 and Class W, there
is no initial sales charge or CDSC.

- --------------------------------------------------------------------------------
S.11

OPENING AN ACCOUNT

Financial institutions are required by law to obtain certain personal
information from each person who opens an account in order to verify the
identity of the person. As a result, when you open an account you will be asked
to provide your name, permanent street address, date of birth, and Social
Security or Employer Identification number. You may also be asked for other
identifying documents or information. If you do not provide this information,
the financial institution through which you are investing in the fund may not be
able to open an account for you. If the financial institution through which you
are investing in the fund is unable to verify your identity, your account may be
closed, or other steps may be taken, as deemed appropriate.

When you buy shares, your order will be priced at the next NAV calculated after
your order is accepted by the fund or an authorized financial institution.

You may establish and maintain your account with an authorized financial
institution or directly with the fund. The fund may appoint servicing agents to
accept purchase orders and to accept exchange (and sale) orders on its behalf.
Accounts maintained by the fund will be supported by the fund's transfer agent.

METHODS OF PURCHASING SHARES

These methods of purchasing shares generally apply to Class A, Class B, and
Class C shares.

ACCOUNT ESTABLISHED WITH YOUR FINANCIAL INSTITUTION

ALL REQUESTS The financial institution through which you buy shares may have
different policies not described in this prospectus, including
different minimum investment amounts and minimum account balances.

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

ACCOUNT ESTABLISHED WITH THE FUND

BY MAIL You or the financial institution through which you buy shares
may establish an account directly with the fund. To establish
an account in this fashion, complete a RiverSource funds
account application with your financial advisor or investment
professional, and mail the account application to the address
below. Account applications may be obtained at
riversource.com or may be requested by calling (888) 791-
3380. Make your check payable to the fund. The fund does not
accept cash, credit card convenience checks, money orders,
traveler's checks, starter checks, third or fourth party
checks, or other cash equivalents.

Mail your check and completed application to:

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

- --------------------------------------------------------------------------------
S.12

METHODS OF PURCHASING SHARES (CONTINUED)

ACCOUNT ESTABLISHED WITH THE FUND (CONT.)

BY MAIL (CONT.)

REGULAR MAIL RIVERSOURCE FUNDS
P.O. BOX 8041
BOSTON, MA 02266-8041

EXPRESS MAIL RIVERSOURCE FUNDS
C/O BFDS
30 DAN ROAD
CANTON, MA 02021-2809

If you already have an account, include your name, account
number, and the name of the fund and class of shares you wish
to purchase along with your check. You can make scheduled
investments in the fund by moving money from your checking
account or savings account. See the Minimum Investment and
Account Balance chart below for more information regarding
scheduled investment plans.

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

BY WIRE OR ACH Fund shares purchased in an account established and
maintained with the fund may be paid for by federal funds
wire. Before sending a wire, call (888) 791-3380 to notify
the fund's transfer agent of the wire and to receive further
instructions.

If you are establishing an account with a wire purchase, you
are required to send a signed account application to the
address above. Please include the wire control number or your
new account number on the application.

Your bank or financial institution may charge additional fees
for wire transactions.

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

BY EXCHANGE Call (888) 791-3380 or send signed written instructions to
the address above.

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

- --------------------------------------------------------------------------------
S.13

MINIMUM INVESTMENT AND ACCOUNT BALANCE

FOR ALL FUNDS, RIVERSOURCE 120/20
CLASSES AND CONTRARIAN
ACCOUNTS EXCEPT RIVERSOURCE EQUITY FUND
THOSE LISTED TO DISCIPLINED THREADNEEDLE
THE RIGHT TAX QUALIFIED SMALL CAP GLOBAL EXTENDED
(NONQUALIFIED) ACCOUNTS VALUE FUND ALPHA FUND CLASS W

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

INITIAL INVESTMENT $2,000 $1,000 $5,000 $10,000 $500
- -------------------------------------------------------------------------------------------------------------

ADDITIONAL INVESTMENTS $100 $100 $100 $100 None
- -------------------------------------------------------------------------------------------------------------

ACCOUNT BALANCE* $300 None $2,500 $5,000 $500

*If your fund account balance falls below the minimum account balance for
any reason, including a market decline, you may be asked to increase it to
the minimum account balance or establish a scheduled investment plan. If
you do not do so within 30 days, your shares may be automatically redeemed
and the proceeds mailed to you.
-------------------------------------------------------------------------------

MINIMUM INVESTMENT AND ACCOUNT BALANCE -- SCHEDULED INVESTMENT PLANS

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

INITIAL INVESTMENT $100 $100 $5,000 $10,000 $500
- -------------------------------------------------------------------------------------------------------------

ADDITIONAL INVESTMENTS $100 $50 $100 $100 None
- -------------------------------------------------------------------------------------------------------------

ACCOUNT BALANCE** None None $2,500 $5,000 $500

**If your fund account balance is below the minimum initial investment
described above, you must make payments at least monthly.
-------------------------------------------------------------------------------

These minimums may be waived for accounts that are managed by an investment
professional, for accounts held in approved discretionary or non-discretionary
wrap programs, for accounts that are a part of an employer-sponsored retirement
plan, or for other account types if approved by the distributor.

The fund reserves the right to modify its minimum account requirements at any
time, with or without prior notice.

Please contact your financial institution for information regarding wire or
electronic funds transfer.

IMPORTANT: Payments sent by electronic fund transfers (ACH), a bank
authorization or check that are not guaranteed may take up to 10 days to clear.
If you request a sale within 10 days of purchase, this may cause your sale
request to fail to process if the requested amount includes unguaranteed funds.

- --------------------------------------------------------------------------------
S.14

EXCHANGING OR SELLING SHARES

You may exchange or sell shares by having your financial institution process
your transaction. If your account is maintained directly with your financial
institution, you must contact that financial institution to exchange or sell
shares of the fund. If your account was established with the fund, there are a
variety of methods you may use to exchange or sell shares of the fund.

WAYS TO REQUEST AN EXCHANGE OR SALE OF SHARES

ACCOUNT ESTABLISHED WITH YOUR FINANCIAL INSTITUTION

ALL REQUESTS You can exchange or sell shares by having your financial
institution process your transaction. The financial
institution through which you purchased shares may have
different policies not described in this prospectus,
including different transaction limits, exchange policies and
sale procedures.

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

ACCOUNT ESTABLISHED WITH THE FUND

BY MAIL Mail your exchange or sale request to:

REGULAR MAIL RIVERSOURCE FUNDS
P.O. BOX 8041
BOSTON, MA 02266-8041

EXPRESS MAIL RIVERSOURCE FUNDS
C/O BFDS
30 DAN ROAD
CANTON, MA 02021-2809

Include in your letter:

- your name

- the name of the fund(s)

- your account number

- the class of shares to be exchanged or sold

- your Social Security number or Employer Identification
number

- the dollar amount or number of shares you want to exchange
or sell

- specific instructions regarding delivery or exchange
destination

- signature(s) of registered account owner(s)

- any special documents the transfer agent may require in
order to process your order

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- --------------------------------------------------------------------------------
S.15

WAYS TO REQUEST AN EXCHANGE OR SALE OF SHARES (CONTINUED)

ACCOUNT ESTABLISHED WITH THE FUND (CONT.)

BY MAIL (CONT.)

Corporate, trust or partnership accounts may need to send
additional documents.

Payment will be mailed to the address of record and made
payable to the names listed on the account, unless your
request specifies differently and is signed by all owners.

A Medallion Signature Guarantee is required if:

- Amount is over $50,000.

- You want your check made payable to someone other than
yourself.

- Your address has changed within the last 30 days.

- You want the check mailed to an address other than the
address of record.

- You want the proceeds sent to a bank account not on file.

- You are the beneficiary of the account and the account
owner is deceased (additional documents may be required).

A Medallion Signature Guarantee assures that a signature is
genuine and not a forgery. The financial institution
providing the Guarantee is financially liable for the
transaction if the signature is a forgery. Eligible
guarantors include commercial banks, trust companies, savings
associations, and credit unions as defined by the Federal
Deposit Insurance Act. Note: A guarantee from a notary public
is not acceptable.

NOTE: Any express mail delivery charges you pay will vary
depending on domestic or international delivery instructions.

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

BY TELEPHONE Call (888) 791-3380. Unless you elect not to have telephone
exchange and sale privileges, they will automatically be
available to you. Reasonable procedures will be used to
confirm authenticity of telephone exchange or sale requests.
Telephone privileges may be modified or discontinued at any
time. Telephone exchange and sale privileges automatically
apply to all accounts except custodial, corporate or
qualified retirement accounts. You may request that these
privileges NOT apply by writing to the address above.

Payment will be mailed to the address of record and made
payable to the names listed on the account.

Telephone sale requests are limited to $100,000 per day.

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

- --------------------------------------------------------------------------------
S.16

WAYS TO REQUEST AN EXCHANGE OR SALE OF SHARES (CONTINUED)

ACCOUNT ESTABLISHED WITH THE FUND (CONT.)

BY WIRE OR ACH You can wire money from your fund account to your bank
account. Make sure we have your bank account information on
file. If we do not have this information, you will need to
send written instructions with your bank's name and a voided
check or savings account deposit slip.

Call (888) 791-3380 or send a letter of instruction, with a
Medallion Signature Guarantee if required, to the address
above.

A service fee may be charged against your account for each
wire sent.

Minimum amount: $100

Your bank or financial institution may charge additional fees
for wire transactions.

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

BY SCHEDULED You may elect to receive regular periodic payments through an
PAYOUT PLAN automatic sale of shares. See the SAI for more information.

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

EXCHANGES

Generally, you may exchange your fund shares for shares of the same class of any
other publicly offered RiverSource fund without a sales charge. For complete
information on the fund you are exchanging into, including fees and expenses,
read that fund's prospectus carefully. Your exchange will be priced at the next
NAV calculated after your transaction request is received in good order. You may
be subject to a sales charge if you exchange from a money market fund into an
equity or fixed income fund.

SHORT-TERM TRADING AND OTHER SO-CALLED MARKET TIMING PRACTICES ARE FREQUENT
TRADING PRACTICES BY CERTAIN SHAREHOLDERS INTENDED TO PROFIT AT THE EXPENSE OF
OTHER SHAREHOLDERS BY SELLING SHARES OF A FUND SHORTLY AFTER PURCHASE. MARKET
TIMING MAY ADVERSELY IMPACT A FUND'S PERFORMANCE BY PREVENTING THE INVESTMENT
MANAGER FROM FULLY INVESTING THE ASSETS OF THE FUND, DILUTING THE VALUE OF
SHARES HELD BY LONG-TERM SHAREHOLDERS, OR INCREASING THE FUND'S TRANSACTION
COSTS.

FUNDS THAT INVEST IN SECURITIES THAT TRADE INFREQUENTLY MAY BE VULNERABLE TO
MARKET TIMERS WHO SEEK TO TAKE ADVANTAGE OF INEFFICIENCIES IN THE SECURITIES
MARKETS. FUNDS THAT INVEST IN SECURITIES THAT TRADE ON OVERSEAS SECURITIES
MARKETS MAY BE VULNERABLE TO MARKET TIMERS WHO SEEK TO TAKE ADVANTAGE OF CHANGES
IN THE VALUES OF SECURITIES BETWEEN THE CLOSE OF OVERSEAS MARKETS AND THE CLOSE
OF U.S. MARKETS, WHICH IS GENERALLY THE TIME AT WHICH A FUND'S NAV

- --------------------------------------------------------------------------------
S.17

IS CALCULATED. TO THE EXTENT THAT A FUND HAS SIGNIFICANT HOLDINGS OF SMALL CAP
STOCKS OR FOREIGN SECURITIES, THE RISKS OF MARKET TIMING MAY BE GREATER FOR THE
FUND THAN FOR OTHER FUNDS. SEE "PRINCIPAL INVESTMENT STRATEGIES" FOR A
DISCUSSION OF THE TYPES OF SECURITIES IN WHICH YOUR FUND INVESTS.

SEE "VALUING FUND SHARES" FOR A DISCUSSION OF THE RIVERSOURCE FUNDS' POLICY ON
FAIR VALUE PRICING, WHICH IS INTENDED, IN PART, TO REDUCE THE FREQUENCY AND
EFFECT OF MARKET TIMING.

THE RIVERSOURCE FUNDS' BOARD HAS ADOPTED A POLICY THAT IS DESIGNED TO DETECT AND
DETER MARKET TIMING THAT MAY BE HARMFUL TO THE FUNDS. EACH FUND SEEKS TO ENFORCE
THIS POLICY THROUGH ITS SERVICE PROVIDERS AS FOLLOWS:

- - The fund tries to distinguish market timing from trading that it believes is
not harmful, such as periodic rebalancing for purposes of asset allocation or
dollar cost averaging or other purchase and exchange transactions not believed
to be inconsistent with the best interest of fund shareholders or the Board's
policy. The fund uses a variety of techniques to monitor for and detect
abusive trading practices. These techniques may vary depending on the type of
fund, the class of shares and where the shares are maintained. Under the
fund's procedures, there is no set number of transactions in the fund that
constitutes market timing. Even one purchase and subsequent sale by related
accounts may be market timing. Generally, the fund seeks to restrict the
exchange privilege of an investor who makes more than three exchanges into or
out of the fund in any 90-day period. Accounts held by a retirement plan or a
financial institution for the benefit of its participants or clients, which
typically engage in daily transactions, are not subject to this limit,
although the fund may seek the assistance of financial institutions in
applying similar restrictions on their participants or clients. The fund's
ability to monitor and discourage abusive trading practices in omnibus
accounts is more limited.

- - The fund may rely on the monitoring policy of a financial institution, for
example, a retirement plan administrator or similar authorized financial
institution authorized to distribute the funds, if it determines the policy
and procedures of such financial institutions are sufficient to protect the
fund and its shareholders.

- - If an investor's trading activity is determined to be market timing or
otherwise harmful to existing shareholders, the fund reserves the right to
modify or discontinue the investor's exchange privilege or reject the
investor's purchases or exchanges, including purchases or exchanges accepted
by a financial institution. The fund may treat accounts it believes to be
under common control as a single account for these purposes, although it may
not be able to identify all such accounts.

- --------------------------------------------------------------------------------
S.18

- - Although the fund does not knowingly permit market timing, it cannot guarantee
that it will be able to identify and restrict all short-term trading activity.
The fund receives purchase and sale orders through financial institutions
where market timing activity may not always be successfully detected.

Other exchange policies:

- - Exchanges must be made into the same class of shares of the new fund.

- - Exchanges into RiverSource Tax-Exempt Money Market Fund may be made only from
Class A shares.

- - If your exchange creates a new account, it must satisfy the minimum investment
amount for new purchases.

- - Once the fund receives your exchange request, you cannot cancel it.

- - Shares of the new fund may not be used on the same day for another exchange or
sale.

- - Shares of Class W originally purchased, but no longer held in a discretionary
managed account, may not be exchanged for Class W shares of another fund. You
may continue to hold these shares in the fund. Changing your investment to a
different fund will be treated as a sale and purchase, and you will be subject
to applicable taxes on the sale and sales charges on the purchase of the new
fund.

- - If your shares are subject to a CDSC, you will not be charged a CDSC upon the
exchange of those shares. Any CDSC will be deducted when you sell the shares
you received from the exchange. The CDSC imposed at that time will be based on
the period that begins when you bought shares of the original fund and ends
when you sell the shares of the fund you exchanged to.

SELLING SHARES

You may sell your shares at any time. The payment will be sent within seven days
after your request is received in good order.

When you sell shares, the amount you receive may be more or less than the amount
you invested. Your sale price will be the next NAV calculated after your request
is received in good order, minus any applicable CDSC.

REPURCHASES. You can change your mind after requesting a sale of shares and use
all or part of the sale proceeds to purchase new shares of RiverSource funds. If
your original purchase was in Class A or Class B, you may use all or part of the
sale proceeds to purchase new Class A shares in any RiverSource fund account
linked together for ROA purposes. Your repurchase will be in Class A shares at
NAV, up to the amount of the sale proceeds. Repurchases of Class B shares will
also be in Class A shares at NAV. Any CDSC paid upon redemption of your Class B
shares will not be reimbursed. If your original purchase was in Class C, you
will be allowed to reinvest in the same Class C account and fund

- --------------------------------------------------------------------------------
S.19

you originally purchased. In a Class C repurchase, the CDSC you paid will be
reinvested and the shares will be deemed to have the original cost and purchase
date for purposes of applying the CDSC (if any) to subsequent redemptions.
Systematic withdrawals and purchases will be excluded from this policy.

In order for you to take advantage of this repurchase waiver, you must notify
your financial institution within 90 days of the date your sale request was
processed. Contact your financial institution for information on required
documentation. The repurchase privilege may be modified or discontinued at any
time and use of this option may have tax consequences.

The fund reserves the right to redeem in kind.

For more details and a description of other sales policies, please see the SAI.

VALUING FUND SHARES

For classes of shares sold with an initial sales charge, the public offering or
purchase price is the net asset value plus the sales charge. For funds or
classes of shares sold without an initial sales charge, the public offering
price is the NAV.

Orders in good form are priced at the NAV next determined after you place your
order. Good form or good order means that your instructions have been received
in the form required by the fund. This may include, for example, providing the
fund name and account number, the amount of the transaction and all required
signatures. For more information, contact your financial institution.

The NAV is the value of a single share of the fund. The NAV is determined by
dividing the value of the fund's assets, minus any liabilities, by the number of
shares outstanding. The NAV is calculated as of the close of business on the New
York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time, on each day that
the NYSE is open. Securities are valued primarily on the basis of market
quotations. Market quotations are obtained from outside pricing services
approved and monitored under procedures adopted by the Board. Certain short-term
securities with maturities of 60 days or less are valued at amortized cost.

When reliable market quotations are not readily available, investments are
priced at fair value based on procedures adopted by the Board. These procedures
are also used when the value of an investment held by a fund is materially
affected by events that occur after the close of a securities market but prior
to the time as of which the fund's NAV is determined. Valuing investments at
fair value involves reliance on judgment. The fair value of an investment is
likely to differ from any available quoted or published price. To the extent
that a fund has significant holdings of foreign securities or small cap stocks
that may trade infrequently, fair valuation may be used more frequently than for
other funds. The RiverSource funds use an unaffiliated service provider to
assist in determining fair values for foreign securities.

- --------------------------------------------------------------------------------
S.20

Foreign investments are valued in U.S. dollars. Some of a fund's securities may
be listed on foreign exchanges that trade on weekends or other days when the
fund does not price its shares. In that event, the NAV of the fund's shares may
change on days when shareholders will not be able to purchase or sell the fund's
shares.

DISTRIBUTIONS AND TAXES

As a shareholder you are entitled to your share of your fund's net income and
net gains. Each fund distributes dividends and capital gains to qualify as a
regulated investment company and to avoid paying corporate income and excise
taxes.

DIVIDENDS AND CAPITAL GAIN DISTRIBUTIONS

Your fund's net investment income is distributed to you as dividends. Dividends
may be composed of qualified dividend income, which is eligible for preferential
tax rates under current tax law, as well as other ordinary dividend income,
which may include dividends which are non-qualified dividends, interest income
and short-term capital gains. Generally, capital gains are realized when a
security is sold for a higher price than was paid for it. Generally, capital
losses are realized when a security is sold for a lower price than was paid for
it. Typically, each realized capital gain or loss is long-term or short-term
depending on the length of time the fund held the security. Realized capital
gains and losses offset each other. The fund offsets any net realized capital
gains by any available capital loss carryovers. Net short-term capital gains, if
any, are included in net investment income and are taxable as ordinary income
when distributed to the shareholder. Net realized long-term capital gains, if
any, are distributed by the end of the calendar year as capital gain
distributions. If the fund's distributions exceed its current and accumulated
earnings and profits, that portion of the fund's distributions will be treated
as a return of capital to the shareholders to the extent of their basis in their
shares. A return of capital will generally not be taxable; however, any amounts
received in excess of basis are treated as capital gain. Forms 1099 sent to
shareholders report any return of capital.

Certain derivative instruments subject the fund to special tax rules, the effect
of which may be to accelerate income to the fund, defer fund losses, cause
adjustments in the holding periods of fund securities, convert capital gains
into ordinary income and convert short-term capital losses into long-term
capital losses. These rules could therefore affect the amount, timing and
character of distributions to shareholders.

REINVESTMENTS

Dividends and capital gain distributions are automatically reinvested in
additional shares in the same class of the fund, unless you request
distributions in cash. The financial institution through which you purchased
shares may have different policies.

- --------------------------------------------------------------------------------
S.21

Distributions are reinvested at the next calculated NAV after the distribution
is paid. If you choose cash distributions, you will receive cash only for
distributions declared after your request has been processed.

TAXES

If you buy shares shortly before the record date of a distribution, you may pay
taxes on money earned by the fund before you were a shareholder. You will pay
the full pre-distribution price for the shares, then receive a portion of your
investment back as a distribution, which may be taxable.

For tax purposes, an exchange is considered a sale and purchase, and may result
in a gain or loss. A sale is a taxable transaction. Generally, if you sell
shares for less than their cost, the difference is a capital loss or if you sell
shares for more than their cost, the difference is a capital gain. Your gain may
be short term (for shares held for one year or less) or long term (for shares
held for more than one year).

You may not create a tax loss or reduce a tax gain, based on paying a sales
charge, by exchanging shares before the 91(st) day after the day of purchase. If
you buy Class A shares and exchange into another fund before the 91(st) day
after the day of purchase, you may not be able to include the sales charge in
your calculation of tax gain or loss on the sale of the first fund you
purchased. The sales charge may be included in the calculation of your tax gain
or loss on a subsequent sale of the second fund you purchased. For more
information, see the SAI.

Distributions related to shares not held in IRAs or other retirement accounts
are subject to federal income tax and may be subject to state and local taxes in
the year they are declared. You must report distributions on your tax returns,
even if they are reinvested in additional shares.

Shares held in an IRA or qualified retirement account are generally subject to
different tax rules. Taking a distribution from your IRA or qualified retirement
plan may subject you to federal taxes, withholding, penalties and reporting
requirements. Please consult your tax advisor.

Income received by a fund may be subject to foreign tax and withholding. Tax
conventions between certain countries and the U.S. may reduce or eliminate these
taxes.

REITs often do not provide complete tax information until after the calendar
year-end; generally mid to late January and continuing through early February.
Consequently, if your fund has significant investments in REITs, you may not
receive your Form 1099-DIV until February. Other RiverSource funds tax
statements are generally mailed in January.

- --------------------------------------------------------------------------------
S.22

IMPORTANT: This information is a brief and selective summary of some of the tax
rules that apply to an investment in a fund. Because tax matters are highly
individual and complex, you should consult a qualified tax advisor.

GENERAL INFORMATION

AVAILABILITY AND TRANSFERABILITY OF FUND SHARES

Please consult with your financial institution to determine the availability of
the RiverSource funds. RiverSource funds may only be purchased or sold directly
or through financial institutions authorized by the distributor to offer the
RiverSource funds. NOT ALL FINANCIAL INSTITUTIONS ARE AUTHORIZED TO SELL THE
FUNDS. If you set up an account at a financial institution that does not have,
and is unable to obtain, a selling agreement with the distributor of the
RiverSource funds, you will not be able to transfer RiverSource fund holdings to
that account. In that event, you must either maintain your RiverSource fund
holdings with your current financial institution, find another financial
institution with a selling agreement, or sell your shares, paying any applicable
CDSC. Please be aware that transactions in taxable accounts are taxable events
and may result in income tax liability.

ADDITIONAL SERVICES AND COMPENSATION

In addition to acting as the fund's investment manager, RiverSource Investments
and its affiliates also receive compensation for providing other services to the
funds.

Administration Services. Ameriprise Financial, 200 Ameriprise Financial Center,
Minneapolis, Minnesota 55474, provides or compensates others to provide
administrative services to the RiverSource funds. These services include
administrative, accounting, treasury, and other services. Fees paid by a fund
for these services are included under "Other expenses" in the expense table
under "Fees and Expenses."

Custody Services. JPMorgan Chase Bank, N.A., 1 Chase Manhattan Plaza, 19th
Floor, New York, NY 10005, provides custody services to the RiverSource funds.
In addition to paying the custodian for these services, the RiverSource funds
pay for certain transaction fees and out-of-pocket expenses incurred while
providing custody services to the funds. Fees paid by a fund for these services
are included under "Other expenses" in the expense table under "Fees and
Expenses."

Distribution and Shareholder Services. RiverSource Distributors, Inc., 50611
Ameriprise Financial Center, Minneapolis, Minnesota 55474, and Seligman
Advisors, Inc., 100 Park Avenue, New York, New York 10017, (collectively, the
distributor), provide underwriting and distribution services to the RiverSource
funds. Under the Distribution Agreement and related distribution and shareholder
servicing plans, the distributor receives distribution and

- --------------------------------------------------------------------------------
S.23

shareholder servicing fees. The distributor may retain a portion of these fees
to support its distribution and shareholder servicing activity. The distributor
reallows the remainder of these fees (or the full fee) to the financial
institutions that sell fund shares and provide services to shareholders. Fees
paid by a fund for these services are set forth under "Distribution and/or
service (12b-1) fees" in the expense table under "Fees and Expenses." More
information on how these fees are used is set forth under "Investment
Options -- Classes of Shares" and in the SAI. The distributor also administers
any sales charges paid by an investor at the time of purchase or at the time of
sale. See "Shareholder Fees (fees paid directly from your investment)" under
"Fees and Expenses" for the scheduled sales charge of each share class. See
"Buying and Selling Shares, Sales Charges" for variations in the scheduled sales
charges, and for how these sales charges are used by the distributor. See "Other
Investment Strategies and Risks" for the RiverSource funds' policy regarding
directed brokerage.

Transfer Agency Services. RiverSource Service Corporation, 734 Ameriprise
Financial Center, Minneapolis, Minnesota 55474 (the transfer agent or
RiverSource Service Corporation), provides or compensates others to provide
transfer agency services to the RiverSource funds. The RiverSource funds pay the
transfer agent a fee that varies by class, as set forth in the SAI, and
reimburses the transfer agent for its out-of-pocket expenses incurred while
providing these transfer agency services to the funds. Fees paid by a fund for
these services are included under "Other expenses" in the expense table under
"Fees and Expenses." RiverSource Service Corporation pays a portion of these
fees to financial institutions that provide sub-recordkeeping and other services
to fund shareholders. The SAI provides additional information about the services
provided and the fee schedules for the transfer agent agreements.

Plan Administration Services. Under a Plan Administration Services Agreement the
fund pays for plan administration services, including services such as
implementation and conversion services, account set-up and maintenance,
reconciliation and account recordkeeping, education services and administration
to various plan types, including 529 plans, retirement plans and Health Savings
Accounts (HSAs). Fees paid by a fund for these services are included under
"Other expenses" in the expense table under "Fees and Expenses."

PAYMENTS TO FINANCIAL INSTITUTIONS

The distributor and its affiliates make or support additional cash payments out
of their own resources (including profits earned from providing services to the
fund) to financial institutions, including inter-company allocation of resources
or payments to affiliated broker-dealers, in connection with agreements between
the distributor and financial institutions pursuant to which these financial
institutions sell fund shares and provide services to their clients who are
shareholders of the fund. These payments and intercompany allocations
(collectively, "payments") do not change the price paid by investors in the fund
or fund shareholders for the

- --------------------------------------------------------------------------------
S.24

purchase or ownership of fund shares of the fund, and these payments are not
reflected in the fees and expenses of the fund, as they are not paid by the
fund.

In exchange for these payments, a financial institution may elevate the
prominence or profile of the fund within the financial institution's
organization, and may provide the distributor and its affiliates with preferred
access to the financial institution's registered representatives or preferred
access to the financial institution's customers. These arrangements are
sometimes referred to as marketing and/or sales support payments, program and/or
shareholder servicing payments, or revenue sharing payments. These arrangements
create potential conflicts of interest between a financial institution's
pecuniary interest and its duties to its customers, for example, if the
financial institution receives higher payments from the sale of a certain fund
than it receives from the sale of other funds, the financial institution or its
representatives may be incented to recommend or sell shares of the fund where it
receives or anticipates receiving the higher payment instead of other investment
options that may be more appropriate for the customer. Employees of Ameriprise
Financial and its affiliates, including employees of affiliated broker-dealers,
may be separately incented to recommend or sell shares of the fund, as employee
compensation and business unit operating goals at all levels are tied to the
company's success. Certain employees, directly or indirectly, may receive higher
compensation and other benefits as investment in the fund increases. In
addition, management, sales leaders and other employees may spend more of their
time and resources promoting Ameriprise Financial and its subsidiary companies,
including RiverSource Investments and the distributor, and the products they
offer, including the fund.

These payments are typically negotiated based on various factors including, but
not limited to, the scope and quality of the services provided by the financial
institution, its reputation in the industry, its ability to attract and retain
assets, its access to target markets, its customer relationships, the profile
the fund may obtain within the financial institution, and the access the
distributor or other representatives of the fund may have within the financial
institution for advertisement, training or education, including opportunities to
present at or sponsor conferences for the registered representatives of the
financial institution and its customers.

These payments are usually calculated based on a percentage of fund assets owned
through the financial institution and/or as a percentage of fund sales
attributable to the financial institution. Certain financial institutions
require flat fees instead of, or in addition to, these asset-based fees as
compensation for including or maintaining a fund on their platforms, and, in
certain situations, may require the reimbursement of ticket or operational
charges -- fees that a financial institution charges its registered
representatives for effecting transactions in the fund. The amount of payment
varies by financial institution (e.g., initial platform set-up fees, ongoing
maintenance or service fees, or asset or sales based fees).

- --------------------------------------------------------------------------------
S.25

The amount of payments also varies by the type of sale. For instance, purchases
of one fund may warrant a greater or lesser amount of payments than purchases of
another fund. Additionally, sale and maintenance of shares on a stand alone
basis may result in a greater or lesser amount of payments than the sale and
maintenance of shares made through a plan, wrap or other fee-based program.
Payments to affiliates may include payments as compensation to employees of
RiverSource Investments who are licensed by the distributor in respect of
certain sales and solicitation activity on behalf of the fund. These payments
may be and often are significant. Additional information concerning the amount
and calculation of these payments is available in the fund's SAI.

Payments to affiliated broker-dealers are within the range of the payments the
distributor pays to similarly-situated third party financial institutions and
the payments such affiliated broker-dealers receive from third party fund
sponsors related to the sale of their sponsored funds. However, because of the
large amount of RiverSource fund assets (in aggregate) currently held in
customer accounts of the affiliated broker-dealers, the distributor and its
affiliates, in the aggregate, pay significantly more in absolute dollars than
other third-party fund sponsors pay to the affiliated broker-dealers for the
sale and servicing of their sponsored funds. This level of payment creates
potential conflicts of interest which the affiliated broker-dealers seek to
mitigate by disclosure and implementation of internal controls, as well as the
rules and regulations of applicable regulators.

From time to time, to the extent permitted by SEC and FINRA rules and by other
applicable laws and regulations, the distributor and its affiliates may make
other reimbursements or payments to financial institutions or their registered
representatives, including non-cash compensation, in the form of gifts of
nominal value, occasional meals, tickets, or other entertainment, support for
due diligence trips, training and educational meetings or conference
sponsorships, support for recognition programs, and other forms of non-cash
compensation permissible under regulations to which these financial institutions
and their representatives are subject. To the extent these are made as payments
instead of reimbursement, they may provide profit to the financial institution
to the extent the cost of such services was less than the actual expense of the
service.

The financial institution through which you are purchasing or own shares of the
fund has been authorized directly or indirectly by the distributor to sell the
fund and/or to provide services to you as a shareholder of the fund. Investors
and current shareholders may wish to take such payment arrangements into account
when considering and evaluating any recommendations they receive relating to
fund shares. If you have questions regarding the specific details regarding the
payments your financial institution may receive from the distributor or its
affiliates related to your purchase or ownership of the fund, please contact
your financial institution. The SAI contains additional detail regarding
payments made by the distributor to financial institutions.

- --------------------------------------------------------------------------------
S.26

The payments described in this section are in addition to fees paid by the fund
to the distributor under 12b-1 plans, which fees may be used to compensate
financial institutions for the distribution of fund shares and the servicing of
fund shareholders, or paid by the fund to the transfer agent under the transfer
agent agreement or plan administration agreement, which fees may be used to
support networking or servicing fees to compensate financial institutions for
supporting shareholder account maintenance, sub-accounting, plan recordkeeping
or other services provided directly by the financial institution to shareholders
or plans and plan participants, including retirement plans, 529 plans, Health
Savings Account plans, or other plans, where participants beneficially own
shares of the fund.

Financial institutions may separately charge you additional fees. See "Buying
and Selling Shares."

ADDITIONAL MANAGEMENT INFORMATION

MANAGER OF MANAGERS EXEMPTION. The RiverSource funds have received an order from
the Securities and Exchange Commission that permits RiverSource Investments,
subject to the approval of the Board, to appoint a subadviser or change the
terms of a subadvisory agreement for a fund without first obtaining shareholder
approval. The order permits the fund to add or change unaffiliated subadvisers
or change the fees paid to subadvisers from time to time without the expense and
delays associated with obtaining shareholder approval of the change.

RiverSource Investments or its affiliates may have other relationships,
including significant financial relationships, with current or potential
subadvisers or their affiliates, which may create a conflict of interest. In
making recommendations to the Board to appoint or to change a subadviser, or to
change the terms of a subadvisory agreement, RiverSource Investments does not
consider any other relationship it or its affiliates may have with a subadviser,
and RiverSource Investments discloses the nature of any material relationships
it has with a subadviser to the Board.

AFFILIATED PRODUCTS. RiverSource Investments also serves as investment manager
to RiverSource funds which are structured to provide asset-allocation services
to shareholders of those funds by investing in shares of other RiverSource funds
(Funds of Funds) and to discretionary managed accounts that invest exclusively
in RiverSource funds (collectively referred to as "affiliated products"). These
affiliated products, individually or collectively, may own a significant
percentage of the fund's outstanding shares. The fund may experience relatively
large purchases or redemptions from the affiliated products. Although
RiverSource Investments may seek to minimize the impact of these transactions,
for example, by structuring them over a reasonable period of time or through
other measures, the fund may experience increased expenses as it buys and sells
securities to manage transactions for the affiliated products. In addition,
because the affiliated products may own a substantial portion of the fund, a
redemption by one or more affiliated products could cause the fund's expense
ratio to increase as the fund's

- --------------------------------------------------------------------------------
S.27

fixed costs would be spread over a smaller asset base. RiverSource Investments
monitors expense levels and is committed to offering funds that are
competitively priced. RiverSource Investments reports to the Board on the steps
it has taken to manage any potential conflicts. See the SAI for information on
the percent of the fund owned by affiliated products.

CASH RESERVES. A fund may invest its daily cash balance in RiverSource Short-
Term Cash Fund (Short-Term Cash Fund), a money market fund established for the
exclusive use of the RiverSource funds and other institutional clients of
RiverSource Investments. While Short-Term Cash Fund does not pay an advisory fee
to RiverSource Investments, it does incur other expenses, and is expected to
operate at a very low expense ratio. A fund will invest in Short-Term Cash Fund
only to the extent it is consistent with the fund's investment objectives and
policies. Short-Term Cash Fund is not insured or guaranteed by the FDIC or any
other government agency.

FUND HOLDINGS DISCLOSURE. The Board has adopted policies and procedures that
govern the timing and circumstances of disclosure to shareholders and third
parties of information regarding the securities owned by a fund. A description
of these policies and procedures is included in the SAI.

LEGAL PROCEEDINGS. Ameriprise Financial and certain of its affiliates have
historically been involved in a number of legal, arbitration and regulatory
proceedings, including routine litigation, class actions, and governmental
actions, concerning matters arising in connection with the conduct of their
business activities. Ameriprise Financial believes that the fund is not
currently the subject of, and that neither Ameriprise Financial nor any of its
affiliates are the subject of, any pending legal, arbitration or regulatory
proceedings that are likely to have a material adverse effect on the fund or the
ability of Ameriprise Financial or its affiliates to perform under their
contracts with the fund. Information regarding certain pending and settled legal
proceedings may be found in the fund's shareholder reports and in the SAI.
Additionally, Ameriprise Financial is required to make 10-Q, 10-K and, as
necessary, 8-K filings with the Securities and Exchange Commission on legal and
regulatory matters that relate to Ameriprise Financial and its affiliates.
Copies of these filings may be obtained by accessing the SEC website at
www.sec.gov.

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S.28

RiverSource Funds can be purchased from authorized financial institutions. The
fund can be found under the "RiverSource" banner in most mutual fund quotations.

Additional information about the fund and its investments is available in the
fund's SAI, and annual and semiannual reports to shareholders. In the fund's
annual report, you will find a discussion of market conditions and investment
strategies that significantly affected the fund's performance during its most
recent fiscal year. The SAI is incorporated by reference in this prospectus. For
a free copy of the SAI, the annual report, or the semiannual report, or to
request other information about the fund, contact RiverSource Funds or your
financial institution. To make a shareholder inquiry, contact the financial
institution through whom you purchased the fund.

RiverSource Funds
734 Ameriprise Financial Center
Minneapolis, MN 55474
(888) 791-3380

RiverSource Funds information available at RiverSource Investments website
address: riversource.com/funds

You may review and copy information about the fund, including the SAI, at the
Securities and Exchange Commission's (Commission) Public Reference Room in
Washington, D.C. (for information about the public reference room call 1-202-
551-8090). Reports and other information about the fund are available on the
EDGAR Database on the Commission's Internet site at www.sec.gov. Copies of this
information may be obtained, after paying a duplicating fee, by electronic
request at the following E-mail address: publicinfo@sec.gov, or by writing to
the Public Reference Section of the Commission, 100 F Street, N.E., Washington,
D.C. 20549-0102.

Investment Company Act File #811-5696

<Table>

TICKER SYMBOL
Class A: IDEAX Class B: IEMBX Class C: RMCEX Class I: RSRIX
Class R4: -- Class R5: REMFX
</Table>

(RIVERSOURCE INVESTMENTS LOGO) S-6354-99 V (12/08)