Supplement, dated August 11, 2000, to the
             Statement of Additional Information, dated May 1, 2000,
                    of Seligman Portfolios, Inc. (the "Fund")
                                on behalf of its
                             Seligman Bond Portfolio
                           Seligman Capital Portfolio
                       Seligman Cash Management Portfolio
                         Seligman Common Stock Portfolio
                           Seligman Frontier Portfolio
                        Seligman Global Growth Portfolio
                   Seligman Global Smaller Companies Portfolio
                      Seligman Global Technology Portfolio
                       Seligman High-Yield Bond Portfolio
                            Seligman Income Portfolio
                     Seligman International Growth Portfolio
                       Seligman Large-Cap Growth Portfolio
                       Seligman Large-Cap Value Portfolio
                       Seligman Small-Cap Value Portfolio
                        (collectively, the "Portfolios")

     Effective August 11, 2000, the following  disclosure  replaces (a) the last
two full paragraphs in the discussion of  "Calculation  of Performance  Data" on
page 29 and (b) the first and second full paragraphs  under the section "General
Information  --  Custodians"  on page 30 of the Fund's  Statement of  Additional
Information:

Page 29

From time to time, reference may be made in advertisements,  sales literature or
other promotional material (collectively, "Promotional Material") to performance
information,  including mutual fund rankings  prepared by independent  reporting
services  which  monitor the  performance  of mutual  funds,  including  but not
limited to Lipper Analytical Services, Inc. and Morningstar, Inc. In calculating
the total  return of each  Portfolio's  Class 1 and Class 2 shares,  the  Lipper
analysis assumes  investment of all dividends and  distributions  paid, but does
not take into  account  applicable  sales  charges.  Morningstar's  rankings are
calculated using a fund's average annual returns for a certain period and a risk
factor that reflects a fund's performance  relative to three-month Treasury Bill
monthly  returns.  Morningstar's  ratings range from five stars (highest) to one
star (lowest) and represent  Morningstar's  assessment  of the  historical  risk
level and total  return of a fund for 3-, 5-, and  10-year  periods  and,  on an
overall  basis,  based on  weighted-average  of those  periods.  Ratings are not
absolute and do not represent future performance results.

Each  Portfolio's  Promotional  Material  may  disclose (i) the top ten holdings
included  in  the  Portfolio's  portfolio  holdings,  (ii)  market  sectors  and
statistical data describing portfolio composition,  (iii) discussions of general
economic or financial  principals,  (iv) discussions of general economic trends,
(v) descriptions of investment  strategies for each Portfolio (vi)  descriptions
or comparisons of various savings and investment products, which may not include
a Portfolio and (vii) comparisons of investment products (including a Portfolio)
with  relevant  market or  industry  indices  or  appropriate  benchmarks.  Each
Portfolio  may  also  include  calculations,  such as  hypothetical  compounding
examples,  which describe  hypothetical  investment  results.  Such  performance
examples will be based on an express set of  assumptions  and are not indicative
of the future performance of the Portfolio.

From time to time,  each  Portfolio's  Promotional  Materials  may  portray  the
historical  returns of various asset classes.  Such presentations will typically
compare the average annual rates of return of inflation,  U.S.  Treasury  bills,
bonds,  large-cap stocks, and small-cap stocks. There are important  differences
between each of these  investments that should be considered in viewing any such
comparison.  The market value of stocks will fluctuate  with market  conditions,
and small-stock  prices generally will fluctuate more than  large-stock  prices.
Stocks are generally  more volatile than bonds.  In return for this  volatility,
stocks have generally performed better than bonds or cash over time. Bond prices
generally  will  fluctuate  inversely  with  interest  rates  and  other  market
conditions,  and the  prices of bonds  with  longer  maturities  generally  will
fluctuate more than those of  shorter-maturity  bonds.  Interest rates for bonds
may be fixed at the time of issuance,  and payment of principal and interest may
be  guaranteed  by the issuer  and,  in the case of U.S.  Treasury  obligations,
backed by the full faith and credit of the U.S. Treasury.

Each  Portfolio  may also  refer in  Promotional  Material  to  selections  from
editorials  or articles  about the  Portfolio,  including  reprints of comments,
listings  and columns in the  financial  and other  press,  the sources of which
include  BARRON'S,  BUSINESS  WEEK,  CDA/WIESENBERGER  MUTUAL  FUNDS  INVESTMENT
REPORT,  CHRISTIAN  SCIENCE  MONITOR,   FINANCIAL  PLANNING,   FINANCIAL  TIMES,
FINANCIAL WORLD,  FORBES,  FORTUNE,  INDIVIDUAL  INVESTOR,  INVESTMENT  ADVISOR,
INVESTORS  BUSINESS  DAILY,  KIPLINGER'S,  LOS ANGELES  TIMES,  MONEY  MAGAZINE,
MORNINGSTAR, INC., PENSION AND INVESTMENTS, SMART MONEY, THE NEW YORK TIMES, THE
WALL STREET  JOURNAL,  USA TODAY,  U.S. NEWS AND WORLD REPORT,  WORTH  MAGAZINE,
WASHINGTON POST and YOUR MONEY.

Each  Portfolio's  Promotional  Material  may make  reference  to a  Portfolio's
"Beta,"  "Standard  Deviation,"  or "Alpha." Beta  measures the  volatility of a
Portfolio,  as  compared  to  that of the  overall  market.  Standard  deviation
measures  how widely the  Portfolio's  performance  has varied  from its average
performance,  and is an indicator of the  Portfolio's  potential for volatility.
Alpha measures the difference between the returns of a Portfolio and the returns
of the market, adjusted for volatility.

Page 30

"Custodians.

With the exception of each of the Global  Portfolios,  State Street Bank & Trust
Company, 801 Pennsylvania,  Kansas City, Missouri 64105, serves as custodian for
the Fund, and in such capacity holds in a separate account assets received by it
from or for the account of each of the Fund's Portfolios.

Chase Manhattan Bank, One Pierrepont Plaza,  Brooklyn, New York 11201, serves as
custodian for each of the Global  Portfolios,  and in such  capacity  holds in a
separate  account assets received by it from or for the account of each of these
Portfolios of the Fund."

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