MORGAN STANLEY DEAN WITTER & CO
424B3, 2000-09-27
FINANCE SERVICES
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The information in this pricing supplement is not complete and may be changed.
We may not deliver these securities until a final pricing supplement is
delivered. This pricing supplement and the accompanying prospectus and
prospectus supplement do not constitute an offer to sell these securities and
we are not soliciting an offer to buy these securities in any state where the
offer or sale is not permitted.


       Subject to Completion, Pricing Supplement dated September 20, 2000

PROSPECTUS Dated May 18, 2000                      Pricing Supplement No. 37 to
PROSPECTUS SUPPLEMENT                      Registration Statement No. 333-34392
Dated May 18, 2000                                     Dated             , 2000
                                                                 Rule 424(b)(3)


                                  $25,000,000
                        Morgan Stanley Dean Witter & Co.
                          MEDIUM-TERM NOTES, SERIES C
                            Senior Fixed Rate Notes

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

                  Convertible Note PERQS due October 31, 2001

                          Mandatorily Exchangeable For
                   7% Convertible Subordinated Notes due 2005
                                of SEPRACOR INC.

Performance Equity-linked Redemption Quarterly-pay Securities(sm) ("PERQS(sm)")

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

The Convertible Note PERQS will pay interest, computed as described below, but
do not guarantee any return of principal at maturity. Instead the Convertible
Note PERQS will pay at maturity a number of 7% Convertible Subordinated Notes
due 2005 of Sepracor Inc. based on the market price on the determination date
(which we expect to be October 26, 2001) of Sepracor common stock, into which
the Sepracor Notes are convertible, subject to a cap price.

     o    The issue price of each Convertible Note PERQS is $         , which
          represents the value of one-half of a Sepracor Note based on the last
          offer price for the Sepracor Notes, as determined on the day we offer
          the Convertible Note PERQS for initial sale to the public, plus
          accrued but unpaid interest on the Sepracor Notes to but not
          including the issue date of the Convertible Note PERQS. The principal
          amount of each Convertible Note PERQS is $1,000.
     o    We will pay interest on each Convertible Note PERQS. The interest
          payable on the Convertible Note PERQS consists of two components.
          o    We will pay to the holder of each Convertible Note PERQS a
               supplemental coupon at the rate of 10% per annum on the
               principal amount of each Convertible Note PERQS, which will
               result in supplemental coupon payments of $    per year for each
               Convertible Note PERQS. Supplemental coupon payments will be
               paid quarterly, beginning January 31, 2001.
          o    On December 30, 2000 and June 30, 2001, we will also pay to the
               holder of each Convertible Note PERQS an underlying coupon equal
               to one-half the amount of interest, if any, paid semi-annually
               by Sepracor on one Sepracor Note since the preceding interest
               payment date on which an underlying coupon was paid (or the
               original issue date, as applicable) for the Convertible Note
               PERQS. If Sepracor fails to pay interest on the Sepracor Notes,
               we will discontinue payments of the underlying coupon and may at
               our option accelerate the Convertible Note PERQS. We will resume
               payments of the underlying coupon if, when and to the extent
               that Sepracor cures its payment default on the Sepracor Notes
               prior to the maturity or acceleration of the Convertible Note
               PERQS.
     o    At maturity you will receive Sepracor Notes in exchange for each
          Convertible Note PERQS at an exchange ratio. The initial exchange
          ratio is one-half of a Sepracor Note per Convertible Note PERQS.
          However, if, as of the determination date, the value of the number of
          shares of Sepracor common stock into which one Sepracor Note is
          convertible appreciates above      % of the current value of those
          shares, the exchange ratio will be adjusted downward, and you will
          receive less than one-half of a Sepracor Note per Convertible Note
          PERQS.
     o    Sepracor is not involved in this offering of Convertible Note PERQS
          in any way and will have no financial obligation with respect to the
          Convertible Note PERQS.
     o    Investing in Convertible Note PERQS is not equivalent to investing in
          Sepracor Notes or Sepracor common stock.
     o    Application will be made to list the Convertible Note PERQS on the
          American Stock Exchange LLC under the symbol "NPS," subject to
          meeting its listing requirements.

You should read the more detailed description of the Convertible Note PERQS in
this pricing supplement. In particular, you should review and understand the
descriptions in "Summary of Pricing Supplement" and "Description of Convertible
Note PERQS." "Performance Equity-linked Redemption Quarterly-pay Securities"
and "PERQS" are our service marks.

     The Convertible Note PERQS are riskier than ordinary debt securities.
                     See "Risk Factors" beginning on PS-6.

                            -----------------------
                    PRICE $     PER CONVERTIBLE NOTE PERQS
                            -----------------------

                                   Price to     Agent's     Proceeds
                                   Public1    Commissions   to MSDW1
                                   --------   -----------   --------
Per Convertible Note PERQS ........$          $             $
Total..............................$          $             $

1Plus accrued interest, if any, from the Original Issue Date.

                           MORGAN STANLEY DEAN WITTER

<PAGE>


                      (This page intentionally left blank)


                                      PS-2
<PAGE>


                         SUMMARY OF PRICING SUPPLEMENT

     The following summary describes the Convertible Note PERQS we are offering
you in general terms only. You should read the summary together with the more
detailed information that is contained in the rest of this pricing supplement
and in the accompanying prospectus and prospectus supplement. You should
carefully consider, among other things, the matters set forth in "Risk
Factors."

                     Overview of the Convertible Note PERQS

     The Convertible Note PERQS are medium-term debt securities of Morgan
Stanley Dean Witter & Co. mandatorily exchangeable for 7% Convertible
Subordinated Notes due 2005 of Sepracor Inc., which we refer to in this pricing
supplement as the Sepracor Notes. Sepracor Notes are subordinated, unsecured
obligations of Sepracor Inc. and are rated CCC+ by Standard & Poor's Rating
Services, a division of The McGraw Hill Companies, Inc. The number of Sepracor
Notes you will receive for each Convertible Note PERQS will depend in part on
the performance of the common stock, $.10 par value per share, of Sepracor
Inc., which we refer to in this pricing supplement as Sepracor Stock. If the
value of the number of shares of Sepracor Stock into which one Sepracor Note is
convertible, which we refer to as Parity, appreciates to more than    % of its
current level, you will receive less than one-half of one Sepracor Note for
each Convertible Note PERQS you hold at maturity. In this pricing supplement,
"one Sepracor Note" means each $1,000 principal amount of the Sepracor Notes,
and "one Convertible Note PERQS" means each $1,000 principal amount of the
Convertible Note PERQS we are offering to you.

Each Convertible Note             We, Morgan Stanley Dean Witter & Co.,
PERQS costs $                     are offering Mandatorily Exchangeable
                                  Notes due October 31, 2001, which we refer to
                                  as the Convertible Note PERQS. The issue
                                  price of each Convertible Note PERQS is $   ,
                                  which represents the value of one-half of a
                                  Sepracor Note based on the last offer price
                                  for the Sepracor Notes, as determined on the
                                  day we offer the Convertible Note PERQS for
                                  initial sale to the public, plus accrued but
                                  unpaid interest on the Sepracor Notes to but
                                  not including the issue date of the
                                  Convertible Note PERQS.

No guaranteed return              Unlike ordinary debt securities, the
of principal                      Convertible Note PERQS do not guarantee any
                                  return of principal at maturity. Instead the
                                  Convertible Note PERQS are mandatorily
                                  exchangeable for Sepracor Notes at an
                                  exchange ratio that will be adjusted downward
                                  if the aggregate market price of the number
                                  of shares of Sepracor Stock into which one
                                  Sepracor Note is convertible appreciates to
                                  more than    % of its current level, which we
                                  refer to as the maximum parity amount.
                                  Investing in the Convertible Note PERQS is
                                  not equivalent to investing in Sepracor Notes
                                  or in Sepracor Stock.

Interest on the Convertible       We will pay interest on the Convertible
Note PERQS                        Note PERQS. The interest payable on the
                                  Convertible Note PERQS consists of two
                                  components.

                                  o    We will pay to the holder of each
                                       Convertible Note PERQS a supplemental
                                       coupon at the rate of 10% per annum on
                                       the principal amount of each Convertible
                                       Note PERQS, which will result in
                                       supplemental coupon payments of $    per
                                       year for each Convertible Note PERQS.
                                       Supplemental coupon payments will be
                                       paid quarterly, beginning January 31,
                                       2001.

                                  o    On December 30, 2000 and June 30, 2001,
                                       we will also pay to the holder of each
                                       Convertible Note PERQS an underlying
                                       coupon equal to the amount of interest,
                                       if any, paid semi-annually by Sepracor
                                       on one Sepracor Note since the preceding
                                       interest payment date for the
                                       Convertible Note PERQS on which an
                                       underlying coupon was paid (or since the
                                       original issue date, as applicable)
                                       multiplied by the exchange ratio. If
                                       Sepracor fails to pay interest on the
                                       Sepracor Notes, we will discontinue
                                       payments of the underlying coupon and


                                      PS-3
<PAGE>


                                       may at our option accelerate the
                                       Convertible Note PERQS. We will resume
                                       payments of the underlying coupon if,
                                       when and to the extent that Sepracor
                                       cures its payment default on the
                                       Sepracor Notes prior to the maturity or
                                       acceleration of the Convertible Note
                                       PERQS. For additional information about
                                       the acceleration of the Convertible Note
                                       PERQS if there is an event of default
                                       with respect to the Sepracor Notes, see
                                       "Description of Convertible Note
                                       PERQS--Certain Events Affecting the
                                       Sepracor Notes."

                                               Payment at Maturity

Your appreciation                 At maturity, for each Convertible Note PERQS
potential is capped               you hold, we will deliver to you a number of
                                  Sepracor Notes equal to the exchange ratio.
                                  The value of the exchange ratio will depend
                                  on whether final parity is greater than the
                                  maximum parity amount. Parity at any date is
                                  the aggregate market price of the number of
                                  shares of Sepracor Stock into which one
                                  Sepracor Note would be convertible on such
                                  date. The maximum parity amount is $       ,
                                  which is     % of the aggregate value of the
                                  number of shares of Sepracor Stock into which
                                  one Sepracor Convertible Note PERQS was
                                  convertible on the day we priced the
                                  Convertible Note PERQS we are offering to
                                  you.

                                  o    If final parity is less than or equal to
                                       the maximum parity amount, the exchange
                                       ratio will equal 0.5.

                                  o    If final parity is greater than the
                                       maximum parity amount, the exchange
                                       ratio will equal 0.5 minus the parity
                                       excess fraction.

                                  The parity excess fraction is a fraction
                                  equal to:

                             final parity minus the maximum parity amount
                             -------------------------------------------- x 0.5
                                          final note price

                                  We will determine final parity based on the
                                  market price of Sepracor Stock on the
                                  determination date, which we expect will be
                                  October 26, 2001, subject to certain market
                                  disruption events. See "Description of
                                  Convertible Note PERQS--Determination Date."
                                  The final note price will be the highest bid
                                  price for Sepracor Notes on the determination
                                  date, subject to availability of a sufficient
                                  number of bids on that date. See "Description
                                  of Convertible Note PERQS--Final Note Price."

Sepracor Stock is currently       Sepracor Stock is currently listed on the
$        per share                NASDAQ National Market. As of the day we
                                  priced the Convertible Note PERQS, the market
                                  price of Sepracor Stock was $    and the last
                                  offer price of the Sepracor Notes was $     .
                                  You can review the historical prices of
                                  Sepracor Stock and the Sepracor Notes in the
                                  "Description of Convertible Note
                                  PERQS--Historical Information" section of
                                  this pricing supplement.

Sepracor Notes are not listed     Sepracor Notes are not listed or traded on an
on an exchange                    organized securities exchange. Accordingly,
                                  there are no published prices at which the
                                  Sepracor Notes that you will receive at
                                  maturity of the Convertible Notes PERQS may
                                  be sold. We cannot assure you that there will
                                  be any market for the Sepracor Notes.


                                      PS-4
<PAGE>


The Calculation Agent             We have appointed Morgan Stanley & Co.
                                  Incorporated ("MS & Co.") to act as
                                  calculation agent for The Chase Manhattan
                                  Bank, the trustee for the Convertible Note
                                  PERQS. As calculation agent, MS & Co. will
                                  determine the market price of the Sepracor
                                  Stock, the prices of the Sepracor Notes and
                                  the number of Sepracor Notes that you receive
                                  at maturity.

No Affiliation with               Sepracor Inc. is not an affiliate of ours and
Sepracor Inc.                     is not involved with this offering in any way.
                                  The obligations represented by the
                                  Convertible Note PERQS are obligations of
                                  Morgan Stanley Dean Witter & Co. and not of
                                  Sepracor Inc. At maturity you will receive
                                  Sepracor Notes in exchange for our
                                  Convertible Notes PERQS. The Sepracor Notes
                                  are rated CCC+ by Standard & Poor's Rating
                                  Services, which is lower than the rating
                                  assigned to our senior debt by that service.

More information on               The Convertible Note PERQS are senior notes
the Convertible Note              issued as part of our Series C medium-term
PERQS                             note program. You can find a general
                                  description of our Series C medium-term note
                                  program in the accompanying prospectus
                                  supplement dated May 18, 2000. We describe
                                  the basic features of this type of note in
                                  the sections called "Description of
                                  Notes--Fixed Rate Notes" and "--Exchangeable
                                  Notes."

                                  For a detailed description of the terms of
                                  the Convertible Note PERQS including the
                                  specific mechanics and timing of the payment
                                  determinations, you should read the
                                  "Description of Convertible Note PERQS"
                                  section in this pricing supplement. You
                                  should also read about some of the risks
                                  involved in investing in Convertible Note
                                  PERQS in the section called "Risk Factors."
                                  The tax and accounting treatment of
                                  investments in equity-linked notes such as
                                  the Convertible Note PERQS may differ from
                                  that of investments in ordinary debt
                                  securities, convertible debt or common stock.
                                  We urge you to consult with your investment,
                                  legal, tax, accounting and other advisers
                                  with regards to any proposed or actual
                                  investment in the Convertible Note PERQS and
                                  confirm that such an investment meets your
                                  particular investment requirements.

More information on               You can obtain information about Sepracor
Sepracor Inc., the Sepracor       Inc., the Sepracor Notes and Sepracor Stock
Notes and Sepracor Stock          from the sources listed under "Description of
                                  Convertible Note PERQS--Public Information
                                  Regarding Sepracor, the Sepracor Notes and
                                  Sepracor Stock," including the Securities and
                                  Exchange Commission (the "SEC"). In
                                  particular, you should read the descriptions
                                  of the Sepracor Notes and Sepracor Stock
                                  contained in Sepracor Inc.'s SEC filings.

How to reach us                   Please contact our principal executive offices
                                  at 1585 Broadway, New York, New York 10036,
                                  telephone number (212) 761-4000.


                                      PS-5
<PAGE>


                                  RISK FACTORS

     The Convertible Note PERQS are not secured debt and are riskier than
ordinary debt securities. Because they are exchangeable at maturity for
Sepracor Notes, there is no guaranteed return of principal. If the value of
Sepracor Notes decreases from the date we offer the Convertible Note PERQS for
initial sale to the public, investors may lose money on their investment. The
Convertible Note PERQS are not equivalent to investing directly in Sepracor
Stock or the Sepracor Notes. Among other differences, investors in the
Convertible Note PERQS will not receive any dividends paid on Sepracor Stock
and investors in the Convertible Note PERQS may receive less than one-half of a
Sepracor Note in exchange for each Convertible Note PERQS at maturity. This
section describes the most significant risks relating to the Convertible Note
PERQS. You should carefully consider whether the Convertible Note PERQS are
suited to your particular circumstances before you decide to purchase them.

The Convertible Note              The Convertible Note PERQS combine features
PERQS are not Ordinary            of equity and debt instruments. Because the
Senior Notes -- You May           prices of the Sepracor Notes and the Sepracor
Lose Money                        Stock into which the Sepracor Notes are
                                  convertible are each subject to market
                                  fluctuations, the value of the Sepracor Notes
                                  you receive upon exchange at maturity may be
                                  less than the issue price of the Convertible
                                  Note PERQS. An investment in the Convertible
                                  Note PERQS may result in an investment loss
                                  if the sum of (i) the total interest payments
                                  on a Convertible Note PERQS and (ii) the
                                  value of the Sepracor Notes delivered in
                                  exchange for a Convertible Note PERQS is less
                                  than the issue price of the Convertible Note
                                  PERQS.

Sepracor Credit Risk              Because our payment of the underlying coupon
                                  on the Convertible Note PERQS is contingent
                                  on Sepracor's payment of interest on the
                                  Sepracor Notes, you will take credit risk
                                  with respect to Sepracor on those interest
                                  payments, as well as on the Sepracor Notes
                                  that you will receive upon exchange at
                                  maturity. In addition, if we become aware of
                                  an event of default with respect to the
                                  Sepracor Notes, we will have the right to
                                  accelerate the Convertible Note PERQS, in
                                  which case we will distribute to you Sepracor
                                  Notes at the exchange ratio plus (a) any
                                  amount paid to holders of Sepracor Notes by
                                  Sepracor at the exchange ratio and any
                                  accrued and unpaid supplemental coupon and
                                  (b) the present value of any future
                                  supplemental coupons. The Sepracor Notes are
                                  rated CCC+ by Standard & Poor's Rating
                                  Services.

Secondary Trading                 There may be little or no secondary market
May be Limited                    for the Convertible Note PERQS. Although we
                                  will apply to list the Convertible Note PERQS
                                  on the American Stock Exchange LLC, which we
                                  refer to as the AMEX, we may not meet the
                                  requirements for listing. Even if there is a
                                  secondary market, it may not provide
                                  significant liquidity. MS & Co. currently
                                  intends to act as a market maker for
                                  Convertible Note PERQS but is not required to
                                  do so.

Market Price of the               Several factors, many of which are beyond our
Convertible Note PERQS            control, will influence the value of the
Influenced                        Convertible Note PERQS. We expect that
by Many Unpredictable             generally the market price of the Sepracor
Factors                           Notes on any day will affect the value of the
                                  Convertible Note PERQS more than any other
                                  single factor. Other factors that may
                                  influence the value of the Convertible Note
                                  PERQS include:


                                  o     the market price of Sepracor Stock

                                  o     the creditworthiness of Sepracor

                                  o     the volatility (frequency and magnitude
                                        of changes in price) of the Sepracor
                                        Stock

                                  o     the dividend rate on Sepracor Stock


                                      PS-6
<PAGE>


                                  o    economic, financial, regulatory and
                                       political events that affect stock
                                       markets generally and which may affect
                                       the market price of the Sepracor Notes
                                       and Sepracor Stock

                                  o    interest and yield rates in the market

                                  o    the time remaining to the maturity of
                                       the Convertible Note PERQS

                                  o    our creditworthiness

                                  Some or all of these factors will influence
                                  the price you receive if you sell your
                                  Convertible Note PERQS prior to maturity. For
                                  example, you may have to sell your
                                  Convertible Note PERQS at a substantial
                                  discount from their issue price if the market
                                  value of the Sepracor Notes is at or below
                                  their initial market value.

                                  You cannot predict the future performance of
                                  the Sepracor Notes or Sepracor Stock based on
                                  their historical performance. The price of
                                  the Sepracor Notes may decrease so that you
                                  will receive at maturity Sepracor Notes worth
                                  less than the issue price of the Convertible
                                  Note PERQS. We cannot guarantee that the
                                  price of the Sepracor Notes will increase so
                                  that you will receive at maturity Sepracor
                                  Notes worth more than the issue price of the
                                  Convertible Note PERQS or that parity will
                                  not increase above the maximum parity amount.
                                  If final parity is more than the maximum
                                  parity amount, the exchange ratio will be
                                  adjusted downward so that you will receive
                                  less than one-half of a Sepracor Note for
                                  each Convertible Note PERQS exchanged at
                                  maturity.

Anti-dilution Adjustments         The adjustments, if any, for corporate events
may be Incomplete or              may affect Sepracor or the market price of the
Commercially Unreasonable         Sepracor Stock (such as stock splits,
                                  extraordinary dividends, tender offers and
                                  mergers) are contained in the Sepracor Notes.
                                  No such adjustments are contained in the
                                  Convertible Note PERQS. We bear no
                                  responsibility for the provisions for such
                                  corporate events, even if those provisions
                                  are incomplete in any material respect or
                                  produce a commercially unreasonable result.

                                  If, as a result of a merger or other
                                  corporate event affecting Sepracor, the
                                  Sepracor Notes become convertible into cash
                                  or other property other than equity
                                  securities (either entirely or above a
                                  specified minimum level), we will accelerate
                                  the Convertible Note PERQS, in which case we
                                  will distribute to you only Sepracor Notes at
                                  the exchange ratio and any accrued and unpaid
                                  supplemental coupon. Upon an acceleration in
                                  these circumstances, we will not pay to you
                                  the present value of any future supplemental
                                  coupons.

No Affiliation with               We are not affiliated with Sepracor.  Although
Sepracor Inc.                     we do not have any non-public information
                                  about Sepracor as of the date of this pricing
                                  supplement, we or our subsidiaries may
                                  presently or from time to time engage in
                                  business with Sepracor, including extending
                                  loans to, or making equity investments in,
                                  Sepracor or providing advisory services to
                                  Sepracor, including merger and acquisition
                                  advisory services. Moreover, we have no
                                  ability to control or predict any actions of
                                  Sepracor, including any corporate actions of
                                  the type that would require the calculation
                                  agent to adjust the exchange ratio at
                                  maturity. Sepracor is not involved in the
                                  offering of the Convertible Note PERQS in any
                                  way and has no obligation to consider your
                                  interest as a holder of Convertible Note
                                  PERQS in taking any corporate actions that
                                  might affect the value of your Convertible
                                  Note PERQS. None of the money you pay for the
                                  Convertible Note PERQS will go to Sepracor.


                                      PS-7
<PAGE>


You Have No Rights as a           As a holder of the Convertible Note PERQS,
Shareholder or Noteholder         you will not be entitled to any rights with
of Sepracor                       respect to Sepracor Notes or Sepracor Stock
                                  (including, without limitation, voting
                                  rights, the rights to receive any dividends
                                  or other distributions (other than interest
                                  actually paid on the Sepracor Notes, to the
                                  extent described herein) and the right to
                                  tender or exchange Sepracor Stock or the
                                  Sepracor Notes in any tender or exchange
                                  offer by Sepracor or any third party) until
                                  such time as we deliver the Sepracor Notes to
                                  you at maturity or, thereafter, Sepracor
                                  delivers Sepracor Stock to you upon
                                  conversion of your Sepracor Notes. As a
                                  holder of the Convertible Note PERQS, you
                                  will not have the right to respond to any
                                  consent solicitation made to holders of the
                                  Sepracor Notes. Any such consent
                                  solicitation, whether or not made in
                                  connection with a tender or exchange offer,
                                  may result in amendments to the indenture for
                                  the Sepracor Notes. Such amendments could
                                  adversely affect the rights of the holders of
                                  Sepracor Notes and the market price of the
                                  Sepracor Notes. For example, a consent
                                  solicitation made in connection with an
                                  exchange offer for the Sepracor Notes could
                                  cause the holders of the Sepracor Notes to
                                  lose the protection of many of the covenants
                                  of Sepracor under the indenture for the
                                  Sepracor Notes. Holding the Convertible Note
                                  PERQS is not the same as owning the
                                  underlying Sepracor Notes.

We May Exercise Rights as         If we, or any of our affiliates, hold
a Holder of Sepracor Notes        Sepracor Notes, including as a result of
                                  hedging activities in connection with the
                                  Convertible Note PERQS, we will have
                                  the right, but not the obligation, to
                                  exercise or to refrain from exercising our
                                  rights as a noteholder, including, without
                                  limitation, rights to tender or exchange
                                  Sepracor Notes in any tender or exchange
                                  offer and to respond to any consent
                                  solicitation issued to holders of the
                                  Sepracor Notes. Any exercise of our rights as
                                  the holder of Sepracor Notes, or our
                                  refraining from any such exercise, could
                                  affect your rights as a holder of the
                                  Sepracor Notes you will receive upon exchange
                                  of the Convertible Note PERQS at maturity.

Potential Conflicts of            As calculation agent, MS & Co. will calculate
Interest between You and          the exchange ratio at maturity of the
the Calculation Agent             Convertible Note PERQS. MS & Co. and other
                                  affiliates may carry out hedging activities
                                  related to Convertible Note PERQS, including
                                  trading in Sepracor Stock or Sepracor Notes
                                  as well as in other instruments related to
                                  Sepracor Stock and Sepracor Notes. MS & Co.
                                  and some of our other subsidiaries also trade
                                  Sepracor Stock and the Sepracor Notes and
                                  other financial instruments related to
                                  Sepracor Stock and Sepracor Notes on a
                                  regular basis as part of their general broker
                                  dealer businesses. Any of these activities
                                  could affect your payout on the Convertible
                                  Note PERQS.

Convertible Note PERQS            These Convertible Note PERQS are exchangeable
are not convertible into the      exclusively into the Sepracor Notes at
common stock or the               maturity.
convertible notes of Morgan
Stanley Dean Witter & Co.

Tax Treatment                     You should also consider the tax consequences
                                  of investing in the Convertible Note PERQS.
                                  There is no direct legal authority as to the
                                  proper tax treatment of the Convertible Note
                                  PERQS, and therefore significant aspects of
                                  the tax treatment of the Convertible Note
                                  PERQS are uncertain. We do not plan to
                                  request a ruling from the Internal Revenue
                                  Service ("IRS") regarding the tax treatment
                                  of the Convertible Note PERQS, and the IRS or
                                  a court may not agree with the tax treatment
                                  described in this pricing supplement. Please
                                  read carefully the section "Description of
                                  Convertible Note PERQS--United States Federal
                                  Income Taxation" in this pricing supplement.


                                      PS-8
<PAGE>


                     DESCRIPTION OF CONVERTIBLE NOTE PERQS

     Capitalized terms not defined herein have the meanings given to such terms
in the accompanying prospectus supplement. The term "Convertible Note PERQS"
refers to the $    aggregate principal amount of our Convertible Note PERQS due
October 31, 2001, Mandatorily Exchangeable for 7% Convertible Subordinated
Notes due 2005 of Sepracor Inc. The term "one Convertible Note PERQS" means
each $1,000 principal amount of the Convertible Note PERQS, and the term "one
Sepracor Note" means each $1,000 principal amount of the Sepracor Notes. In
this pricing supplement, "MSDW," "we," "us" and "our" refer to Morgan Stanley
Dean Witter & Co.

Principal Amount...............   $1,000

Maturity Date..................   October 31, 2001; provided that if on the
                                  Determination Date Final Parity is greater
                                  than the Maximum Parity Amount and the Final
                                  Note Price is not determined on the
                                  Determination Date, as provided under
                                  "--Final Note Price" below, the Maturity Date
                                  shall be the second Trading Day following the
                                  day on which the Calculation Agent determines
                                  the Final Note Price.

Interest Payments..............   We will pay to the holder of each Convertible
                                  Note PERQS (i) a Supplemental Coupon at the
                                  rate of 10% per annum on the Principal Amount
                                  of the Convertible Note PERQS on each
                                  Interest Payment Date for the Supplemental
                                  Coupons, which will result in Supplemental
                                  Coupon payments of $      per year for each
                                  Convertible Note PERQS and (ii) on each
                                  Interest Payment Date for the Underlying
                                  Coupon, an Underlying Coupon equal to the
                                  amount of interest, if any, paid by Sepracor
                                  on one Sepracor Note since the preceding
                                  Interest Payment Date on which an Underlying
                                  Coupon was paid (or since the Original Issue
                                  Date, as applicable) multiplied by the
                                  exchange ratio (subject to the terms
                                  described under "Discontinuance of Underlying
                                  Coupon Payments" below).

Interest Payment Dates for the
  Supplemental Coupon..........   Each January 31, April 30, July 31 and
                                  October 31, beginning January 31, 2001.

Interest Payment Dates for the
  Underlying Coupon............   December 30, 2000 and June 30, 2001.

Specified Currency.............   U.S. dollars

Issue Price....................   $         per Convertible Note PERQS, which
                                  equals one-half of the last offer price for
                                  the Sepracor Notes on the Pricing Date plus
                                  accrued but unpaid interest on Sepracor Notes
                                  to but not including the Original Issue Date.

Initial Sepracor Note Price....   $

Original Issue Date
  (Settlement Date)............   September   , 2000

Pricing Date...................   September   , 2000

CUSIP..........................   61744Y736

Denominations..................   $1,000 and integral multiples thereof


                                      PS-9
<PAGE>


Sepracor Notes.................   7% Convertible Subordinated Notes due 2005 of
                                  Sepracor Inc., or any successor security
                                  (CUSIP 817315AH7). The Sepracor Notes are
                                  convertible into Sepracor Stock.

Sepracor Stock.................   The common stock, par value $0.10 per share,
                                  of Sepracor Inc., a Delaware corporation, or
                                  any successor entity ("Sepracor").

Exchange at Maturity...........   At maturity, upon delivery of each
                                  Convertible Note PERQS to the Trustee, we
                                  will, with respect to the principal amount of
                                  each Convertible Note PERQS, deliver a number
                                  of Sepracor Notes equal to the Exchange
                                  Ratio.

Exchange Ratio.................   If Final Parity is less than or equal to the
                                  Maximum Parity Amount, the Exchange Ratio
                                  will be 0.5. If Final Parity is greater than
                                  the Maximum Parity Amount, the Exchange Ratio
                                  will be 0.5 minus the Parity Excess Fraction.

Final Parity...................   Parity on the Determination Date

Parity.........................   Parity on any date means the aggregate Market
                                  Price of the number of shares of Sepracor
                                  Stock into which one Sepracor Note would be
                                  convertible on such date, as determined by
                                  the Calculation Agent.

Maximum Parity Amount..........   $          , equal to      % of Initial Parity

Initial Parity.................   $          , which is Parity on the Pricing
                                  Date, as determined by the Calculation Agent

Parity Excess Fraction.........   The Parity Excess Fraction is equal to 0.5
                                  times a fraction, the numerator of which will
                                  be Final Parity minus the Maximum Parity
                                  Amount and the denominator of which will be
                                  the Final Note Price.

Final Note Price...............   The Final Note Price will be the highest bid
                                  price for Sepracor Notes, plus accrued but
                                  unpaid interest, obtained from as many
                                  dealers or other institutional purchasers in
                                  the Sepracor Notes (which may include MS &
                                  Co. or any of our other subsidiaries or
                                  affiliates), but not exceeding three, as will
                                  make such bid prices available to the
                                  Calculation Agent on the Determination Date;
                                  provided that such bid prices shall be for a
                                  number of Sepracor Notes, as determined by
                                  the Calculation Agent, approximately equal in
                                  value to the Parity Excess Fraction
                                  multiplied by the aggregate principal amount
                                  of Convertible Note PERQS then outstanding;
                                  provided further that if the Calculation
                                  Agent is unable to obtain at least two such
                                  bid prices on the Determination Date, the
                                  Final Note Price will be determined on the
                                  next succeeding Trading Day on which the
                                  Calculation Agent is able to obtain at least
                                  two such bid prices; provided further that if
                                  the Calculation Agent has not been able to
                                  obtain two such bid prices by the fifth
                                  Trading Day following the Determination Date,
                                  then the Calculation Agent will determine the
                                  Final Note Price on such day in good faith
                                  using its reasonable judgment.

Determination Date.............   October 26, 2001, or if such day is not a
                                  Trading Day or if there is a Market
                                  Disruption Event on such day, the
                                  Determination Date


                                     PS-10
<PAGE>


                                  will be the immediately succeeding Trading
                                  Day during which no Market Disruption Event
                                  shall have occurred; provided that the
                                  Determination Date will be no later than the
                                  second scheduled Trading Day preceding the
                                  scheduled Maturity Date, notwithstanding the
                                  occurrence of a Market Disruption Event on
                                  such second scheduled Trading Day. See also
                                  "-Final Parity" above.

Market Price...................   If Sepracor Stock (or any other security for
                                  which a Market Price must be determined) is
                                  listed on a national securities exchange, is
                                  a security of the Nasdaq National Market or
                                  is included in the OTC Bulletin Board Service
                                  (the "OTC Bulletin Board") operated by the
                                  National Association of Securities Dealers,
                                  Inc. (the "NASD"), the Market Price for one
                                  share of Sepracor Stock (or one unit of any
                                  such other security) on any Trading Day means
                                  (i) the last reported sale price, regular
                                  way, of the principal trading session on such
                                  day on the principal United States securities
                                  exchange registered under the Securities
                                  Exchange Act of 1934, as amended (the
                                  "Exchange Act"), on which Sepracor Stock (or
                                  such other security) is listed or admitted to
                                  trading or (ii) if not listed or admitted to
                                  trading on any such securities exchange or if
                                  such last reported sale price is not
                                  obtainable (even if Sepracor Stock (or such
                                  other security) is listed or admitted to
                                  trading on such securities exchange), the
                                  last reported sale price of the principal
                                  trading session on the over-the-counter
                                  market as reported on the Nasdaq National
                                  Market or OTC Bulletin Board on such day. If
                                  the last reported sale price is not available
                                  pursuant to clause (i) or (ii) of the
                                  preceding sentence because of a Market
                                  Disruption Event or otherwise, the Market
                                  Price for any Trading Day will be the mean,
                                  as determined by the Calculation Agent, of
                                  the bid prices for Sepracor Stock (or any
                                  such other security) obtained from as many
                                  dealers in such security (which may include
                                  MS & Co. or any of its affiliates), but not
                                  exceeding three, as will make such bid prices
                                  available to the Calculation Agent. The term
                                  "securities traded on the Nasdaq National
                                  Market" will include a security included in
                                  any successor to such system and the term
                                  "OTC Bulletin Board Service" will include any
                                  successor service thereto.

Trading Day....................   A day on which trading is generally conducted
                                  on the New York Stock Exchange ("NYSE"), the
                                  AMEX, the Nasdaq National Market, the Chicago
                                  Mercantile Exchange and the Chicago Board of
                                  Options Exchange and in the over-the-counter
                                  market for equity securities in the United
                                  States, as determined by the Calculation
                                  Agent.

Business Day...................   Any day other than a Saturday or Sunday, that
                                  is neither a legal holiday nor a day on which
                                  banking institutions are authorized or
                                  required by law or regulation to close in The
                                  City of New York.

Optional Redemption............   We will not redeem the Convertible Note PERQS
                                  prior to the Maturity Date, and the
                                  Convertible Note PERQS will not be
                                  exchangeable by you prior to the Maturity
                                  Date.

Discontinuance of Underlying
  Coupon Payments..............   If there is a default by Sepracor with
                                  respect to the payment of


                                     PS-11
<PAGE>


                                  interest on the Sepracor Notes, we will
                                  discontinue payments of the Underlying Coupon
                                  on the Convertible Note PERQS and we will
                                  have the right to accelerate the maturity of
                                  the Convertible Note PERQS, as described
                                  under "--Certain Events Affecting the
                                  Sepracor Notes." If we do not accelerate the
                                  maturity of the Convertible Note PERQS, we
                                  will resume payments of the Underlying Coupon
                                  if, when and to the extent that such default
                                  is cured by Sepracor prior to the earlier of
                                  the Determination Date and the Early
                                  Determination Date (as defined under "Certain
                                  Events Affecting the Sepracor Notes" below).
                                  Upon a cure by Sepracor of any such default,
                                  we will promptly, but in no event later than
                                  two Business Days following the date on which
                                  holders of the Sepracor Notes receive a
                                  payment of delinquent interest with respect
                                  to the Sepracor Notes, pay to each holder an
                                  amount per Convertible Note PERQS equal to
                                  the amount of delinquent interest paid by
                                  Sepracor to the holders of a Sepracor Note
                                  multiplied by the Exchange Ratio. Payment of
                                  the Underlying Coupon on the Convertible Note
                                  PERQS will thereafter be paid on the next
                                  applicable succeeding Interest Payment Date,
                                  as described under "--Interest Payments"
                                  above, subject to the conditions set forth in
                                  this paragraph.

                                  A discontinuance of payments of the
                                  Underlying Coupon, whether or not resumed,
                                  pursuant to the immediately preceding
                                  paragraph will not constitute a default under
                                  the Senior Debt Indenture for the Convertible
                                  Note PERQS.

                                  We will, or will cause the Calculation Agent
                                  to, provide written notice to the Trustee at
                                  its New York office, on which notice the
                                  Trustee can conclusively rely, and to the
                                  holders (i) no later than 10:00 a.m. on the
                                  Business Day next succeeding an interest
                                  payment date for the Sepracor Notes of any
                                  default by Sepracor in the payment of
                                  interest on the Sepracor Notes and (ii) no
                                  later than 10:00 a.m. on the Business Day
                                  next succeeding any payment of interest on
                                  the Sepracor Notes by Sepracor to cure any
                                  such default of the amount of interest to be
                                  delivered per Convertible Note PERQS.

Certain Events Affecting
the Sepracor Notes.............   Events of Default

                                  If, on any date prior to the Maturity Date,
                                  we become aware of an event of default with
                                  respect to the Sepracor Notes (such date, the
                                  "Default Notice Date"), we will have the
                                  right, but not the obligation on the Default
                                  Notice Date and on any succeeding Trading Day
                                  (to and including the scheduled Trading Day
                                  immediately preceding the Determination Date)
                                  on which such event of default is continuing,
                                  to (i) deliver to the Trustee and the holders
                                  of the Convertible Note PERQS notice of such
                                  event of default (such date, the
                                  "Acceleration Notice Date") and (ii)
                                  accelerate the maturity of the Convertible
                                  Note PERQS and distribute, in exchange for
                                  each Convertible Note PERQS, Sepracor Notes
                                  at the Exchange Ratio, calculated as if the
                                  Acceleration Notice Date were the
                                  Determination Date (the "Early Determination
                                  Date"), plus (a) any accrued and unpaid


                                     PS-12
<PAGE>


                                  Supplemental Coupons to such Early
                                  Determination Date and (b) the present value
                                  of any future Supplemental Coupons calculated
                                  based on the interpolated U.S. dollar zero
                                  swap rate, as determined by the Calculation
                                  Agent (such distribution, an "Early
                                  Distribution"); provided that if the
                                  Acceleration Notice Date is not a Trading Day
                                  or if there is a Market Disruption Event on
                                  such date, the Early Determination Date will
                                  be the next succeeding Trading Day during
                                  which no Market Disruption Event shall have
                                  occurred; provided further that if it is
                                  necessary to determine a Final Note Price and
                                  two bid prices (as described under "--Final
                                  Note Price") are not available on such day,
                                  the Calculation Agent will determine the
                                  Final Note Price in good faith using its
                                  reasonable judgment. We will make any such
                                  Early Distribution on the second Business Day
                                  next succeeding the Early Determination Date
                                  (the "Early Distribution Date"). If the Early
                                  Distribution Date falls after a record date
                                  for the payment of interest on the Sepracor
                                  Notes and prior to the immediately succeeding
                                  interest payment date, we will not pay any
                                  accrued but unpaid Underlying Coupon on the
                                  Early Distribution Date; provided that we
                                  will deliver, with the Sepracor Notes
                                  delivered on the Early Distribution Date,
                                  due-bills or other instruments with respect
                                  to such Sepracor Notes evidencing the
                                  transfer of title to any such interest
                                  payments.

                                  We will, or will cause the Calculation Agent
                                  to (i) provide written notice to the Trustee
                                  at its New York office, on which notice the
                                  Trustee can conclusively rely, and to the
                                  holders of the Convertible Note PERQS on or
                                  prior to 10:30 a.m. on the Business Day
                                  immediately preceding the Early Distribution
                                  Date (A) of the number of Sepracor Notes (and
                                  the amount of any cash) to be delivered per
                                  Convertible Note PERQS and (B) that such
                                  distribution is pursuant to a decision to
                                  accelerate the Convertible Note PERQS as a
                                  result of an event of default with respect to
                                  the Sepracor Notes and (ii) deliver on the
                                  Early Distribution Date the Early
                                  Distribution to the Trustee for delivery to
                                  the holders against delivery of the
                                  Convertible Note PERQS to the Trustee.

                                  If a "Fundamental Change," as described
                                  below, occurs as a result of a liquidation or
                                  other similar event that also constitutes an
                                  event of default, any acceleration of the
                                  Convertible Note PERQS will be made in
                                  accordance with the procedures described
                                  above, rather than in accordance with
                                  procedures related to mergers or other
                                  corporate events described below.

                                  Mergers or Other Corporate Events

                                  If, as a result of a merger or other
                                  corporate event affecting Sepracor, the
                                  Sepracor Notes become convertible solely into
                                  equity securities other than Sepracor Stock,
                                  Parity will be determined, and the Exchange
                                  Ratio will be calculated, by reference to the
                                  Market Price of such other equity securities
                                  (unless such merger or other event
                                  constitutes a Fundamental Change, as defined
                                  below). The terms of the Convertible Note
                                  PERQS will not otherwise change.


                                     PS-13
<PAGE>


                                  If, as the result of such an event, the
                                  Sepracor Notes become convertible into (i)
                                  equity securities other than Sepracor Stock
                                  and (ii) cash or other property other than
                                  equity securities ("Other Merger
                                  Consideration"), then the Calculation Agent
                                  will determine the total value (the "Merger
                                  Consideration Value") of such equity
                                  securities and such Other Merger
                                  Consideration on the date holders of Sepracor
                                  Stock receive such merger consideration (the
                                  "Merger Valuation Date"); provided that if
                                  such day is not a Trading Day, the Merger
                                  Valuation Date will be the next succeeding
                                  Trading Day. The Calculation Agent will make
                                  such determination by reference to (a) the
                                  Market Price of such securities, (b) the
                                  amount of such cash and (c) the fair market
                                  value, as determined by the Calculation
                                  Agent, of any such other property.

                                  If the value of the Other Merger
                                  Consideration on the Merger Valuation Date is
                                  less than or equal to 1% of the Merger
                                  Consideration Value, Parity will be
                                  determined, and the Exchange Ratio will be
                                  calculated, by reference to the Market Price
                                  of such equity securities and the value of
                                  the Other Merger Consideration (unless such
                                  merger or other event constitutes a
                                  Fundamental Change, as defined below). The
                                  terms of the Convertible Note PERQS will not
                                  otherwise change.

                                  If (i) the value of the Other Merger
                                  Consideration on the Merger Valuation Date is
                                  greater than 1% of the Merger Consideration
                                  Value or (ii) such merger or other event
                                  constitutes a "Fundamental Change" under the
                                  terms of the Sepracor Notes, we will
                                  accelerate the Convertible Note PERQS. A
                                  "Fundamental Change" with respect to the
                                  Sepracor Notes means an event which results
                                  in all or substantially all of the shares of
                                  common stock of Sepracor being exchanged for
                                  consideration which is not all or
                                  substantially all common stock which is
                                  listed on a national securities exchange or
                                  automated quotation system. We have derived
                                  this information about the Sepracor Notes
                                  entirely from the public disclosure on the
                                  Sepracor Notes described under "--Public
                                  Information Regarding Sepracor, the Sepracor
                                  Notes and Sepracor Stock" below and have made
                                  no due diligence inquiry with respect to such
                                  information.

                                  If, as a result of a merger or other
                                  corporate event affecting Sepracor, the
                                  Sepracor Notes become convertible solely into
                                  Other Merger Consideration, we will
                                  accelerate the Convertible Note PERQS.

                                  If we accelerate the Convertible Note PERQS
                                  as a result of a situation described in
                                  either of the two immediately preceding
                                  paragraphs, (i) Parity will be determined,
                                  and the Exchange Ratio will be calculated, by
                                  reference to the Merger Consideration Value
                                  and (ii) we will distribute, in exchange for
                                  each Convertible Note PERQS, Sepracor Notes
                                  at the Exchange Ratio, calculated as if the
                                  Merger Valuation Date were the Determination
                                  Date, plus any accrued and unpaid
                                  Supplemental Coupon to such Merger Valuation
                                  Date (such distribution, an "Merger
                                  Distribution"). We will make any such Merger
                                  Distribution on the second Business Day next
                                  succeeding the Merger Valuation Date (the
                                  "Merger


                                     PS-14
<PAGE>


                                  Distribution Date"). If the Merger
                                  Distribution Date falls after a record date
                                  for the payment of interest on the Sepracor
                                  Notes and prior to the immediately succeeding
                                  interest payment date, we will not pay any
                                  accrued but unpaid Underlying Coupon on the
                                  Merger Distribution Date.

                                  We will, or will cause the Calculation Agent
                                  to (i) provide written notice to the Trustee
                                  at its New York office, on which notice the
                                  Trustee can conclusively rely, and to the
                                  holders of the Convertible Note PERQS on or
                                  prior to 10:30 a.m. on the Business Day
                                  immediately preceding the Merger Distribution
                                  Date (A) of the number of Sepracor Notes (and
                                  the amount of any cash) to be delivered per
                                  Convertible Note PERQS and (B) that such
                                  distribution is pursuant to an acceleration
                                  of the Convertible Note PERQS as a result of
                                  a merger or other corporate event with
                                  respect to Sepracor and (ii) deliver on the
                                  Merger Distribution Date the Merger
                                  Distribution to the Trustee for delivery to
                                  the holders against delivery of the
                                  Convertible Note PERQS to the Trustee.

                                  You will not be entitled to tender or
                                  exchange Sepracor Stock or the Sepracor Notes
                                  in any tender or exchange offer by Sepracor
                                  or any third party, nor will you be entitled
                                  to respond to any consent solicitation made
                                  to holders of the Sepracor Notes or have any
                                  other rights, including, without limitation,
                                  voting rights with respect to the Sepracor
                                  Notes or Sepracor stock, until such time as
                                  we deliver the Sepracor Notes to you at
                                  maturity or Sepracor delivers Sepracor Stock
                                  to you upon conversion of your Sepracor
                                  Notes, as applicable.

Book Entry Note or
  Certificated Note............   Book Entry

Senior Note or Subordinated
  Note.........................   Senior

Trustee........................   The Chase Manhattan Bank

Agent for this Underwritten
  Offering of Convertible Note
  PERQS........................   Morgan Stanley & Co. Incorporated

Calculation Agent..............   Morgan Stanley & Co. Incorporated and its
                                  successors ("MS & Co.")

                                  Because the Calculation Agent is our
                                  affiliate, potential conflicts of interest
                                  may exist between the Calculation Agent and
                                  you as holder of the Convertible Note PERQS
                                  with respect to its determinations of the
                                  Exchange Ratio, the Market Price of Sepracor
                                  Stock or the prices of the Sepracor Notes or
                                  of whether a Market Disruption Event has
                                  occurred. See "Market Disruption Event"
                                  below. MS & Co. is obligated to carry out its
                                  duties as Calculation Agent in good faith
                                  using its reasonable judgment.

                                  All percentages resulting from any
                                  calculation on the Convertible Note PERQS
                                  will be rounded to the nearest one hundred-
                                  thousandth of a percentage point, with five
                                  one-millionths of a percentage point rounded
                                  upwards (e.g., 9.876545% (or .09876545) would
                                  be rounded to 9.87655% (or .0987655)), and
                                  all


                                     PS-15
<PAGE>


                                  dollar amounts used in or resulting from such
                                  calculation will be rounded to the nearest
                                  cent with one-half cent being rounded
                                  upwards.

Market Disruption Event........   "Market Disruption Event" means, with respect
                                  to Sepracor Stock:

                                  (i) a suspension, absence or material
                                  limitation of trading of Sepracor Stock on
                                  the primary market for Sepracor Stock for
                                  more than two hours of trading or during the
                                  one-half hour period preceding the close of
                                  trading in such market; or a breakdown or
                                  failure in the price and trade reporting
                                  systems of the primary market for Sepracor
                                  Stock as a result of which the reported
                                  trading prices for Sepracor Stock during the
                                  last one-half hour preceding the closing of
                                  trading in such market are materially
                                  inaccurate; or the suspension, absence or
                                  material limitation on the primary market for
                                  trading in options contracts related to
                                  Sepracor Stock, if available, during the
                                  one-half hour period preceding the close of
                                  trading in the applicable market, in each
                                  case as determined by the Calculation Agent
                                  in its sole discretion; and

                                  (ii)a determination by the Calculation Agent
                                  in its sole discretion that the event
                                  described in clause (i) above materially
                                  interfered with the ability of MSDW or any of
                                  its affiliates to unwind all or a material
                                  portion of the hedge with respect to the
                                  Convertible Note PERQS.

                                  For purposes of determining whether a Market
                                  Disruption Event has occurred: (1) a
                                  limitation on the hours or number of days of
                                  trading will not constitute a Market
                                  Disruption Event if it results from an
                                  announced change in the regular business
                                  hours of the relevant exchange, (2) a
                                  decision to permanently discontinue trading
                                  in the relevant option contract will not
                                  constitute a Market Disruption Event, (3)
                                  limitations pursuant to any applicable rule
                                  or regulation enacted or promulgated by the
                                  National Association of Securities Dealers
                                  (or any other self-regulatory organization
                                  with jurisdiction over the Nasdaq National
                                  Market) on trading during significant market
                                  fluctuations shall constitute a suspension,
                                  absence or material limitation of trading,
                                  (4) a suspension of trading in an options
                                  contract on Sepracor Stock by the primary
                                  securities market trading in such options, if
                                  available, by reason of (x) a price change
                                  exceeding limits set by such securities
                                  exchange or market, (y) an imbalance of
                                  orders relating to such contracts or (z) a
                                  disparity in bid and ask quotes relating to
                                  such contracts will constitute a suspension
                                  or material limitation of trading in options
                                  contracts related to Sepracor Stock and (5) a
                                  suspension, absence or material limitation of
                                  trading on the primary securities market on
                                  which options contracts related to Sepracor
                                  Stock are traded will not include any time
                                  when such securities market is itself closed
                                  for trading under ordinary circumstances.

Alternative Determination
  Date in case of an Event
  of Default with respect to
  the Convertible Note PERQS...   In case an Event of Default with respect to
                                  any Convertible Note PERQS shall have
                                  occurred and be continuing, the number of
                                  Sepracor Notes for which each Convertible
                                  Note PERQS will be


                                     PS-16
<PAGE>


                                  exchangeable upon any acceleration of the
                                  Convertible Note PERQS will be determined by
                                  the Calculation Agent as though the
                                  Determination Date were the date of
                                  acceleration. In addition, an amount equal to
                                  any accrued but unpaid Supplemental Coupon to
                                  but not including such date of acceleration
                                  will be due and payable. If the date of
                                  acceleration falls after a record date for
                                  the payment of interest on the Sepracor Notes
                                  and prior to the immediately succeeding
                                  interest payment date, we will not pay any
                                  accrued but unpaid Underlying Coupon on the
                                  date of acceleration.

Public Information Regarding
  Sepracor, the Sepracor Notes
  and Sepracor Stock...........   Sepracor is a specialty pharmaceutical
                                  company focused on the cost-effective
                                  development of safer, purer and more
                                  effective drugs that are improved versions of
                                  widely prescribed pharmaceutical compounds. A
                                  registration statement for the Sepracor Notes
                                  has been filed under the Securities Act of
                                  1933, as amended (the "Securities Act"), and
                                  Sepracor Stock is registered under the
                                  Exchange Act. Companies with securities
                                  registered under the Exchange Act are
                                  required to file periodically certain
                                  financial and other information specified by
                                  the SEC. Information provided to or filed
                                  with the SEC can be inspected and copied at
                                  the public reference facilities maintained by
                                  the SEC at Room 1024, 450 Fifth Street, N.W.,
                                  Washington, D.C. 20549 or at its Regional
                                  Office located at Suite 1400, Citicorp
                                  Center, 500 West Madison Street, Chicago,
                                  Illinois 60661 and at Seven World Trade
                                  Center, 13th Floor, New York, New York 10048,
                                  and copies of such material can be obtained
                                  from the Public Reference Section of the SEC,
                                  450 Fifth Street, N.W., Washington, D.C.
                                  20549, at prescribed rates. In addition,
                                  information provided to or filed with the SEC
                                  electronically can be accessed through a
                                  Website maintained by the SEC. The address of
                                  the SEC's Website is http://www.sec.gov.
                                  Information provided to or filed with the SEC
                                  by Sepracor pursuant to the Exchange Act can
                                  be located by reference to SEC file number
                                  0-19410. In particular, information regarding
                                  the Sepracor Notes can be found in
                                  Registration Statement No. 333- 75561, and
                                  the Prospectus dated July 25, 1999 contained
                                  therein. According to such filed information,
                                  The Chase Manhattan Bank was the trustee for
                                  the Sepracor Notes at the time of their
                                  issuance. In addition, information regarding
                                  Sepracor may be obtained from other sources
                                  including, but not limited to, press
                                  releases, newspaper articles and other
                                  publicly disseminated documents. We make no
                                  representation or warranty as to the accuracy
                                  or completeness of such reports.

                                  This pricing supplement relates only to the
                                  Convertible Note PERQS offered hereby and
                                  does not relate to Sepracor Stock, the
                                  Sepracor Notes or other securities of
                                  Sepracor. We have derived all disclosures
                                  contained in this pricing supplement
                                  regarding Sepracor from the publicly
                                  available documents described in the
                                  preceding paragraph. Neither we nor the Agent
                                  has participated in the preparation of such
                                  documents or made any due diligence inquiry
                                  with respect to Sepracor in connection with
                                  the offering of the Convertible Note PERQS.
                                  Neither we nor the Agent makes any
                                  representation that such publicly available
                                  documents or any other publicly available


                                     PS-17
<PAGE>


                                  information regarding Sepracor are accurate
                                  or complete. Furthermore, we cannot give any
                                  assurance that all events occurring prior to
                                  the date hereof (including events that would
                                  affect the accuracy or completeness of the
                                  publicly available documents described in the
                                  preceding paragraph) that would affect the
                                  trading price of Sepracor Stock or the
                                  Sepracor Notes have been publicly disclosed.
                                  Subsequent disclosure of any such events or
                                  the disclosure of or failure to disclose
                                  material future events concerning Sepracor
                                  could affect the value received at maturity
                                  with respect to the Convertible Note PERQS
                                  and therefore the trading prices of the
                                  Convertible Note PERQS.

                                  Neither we nor any of our affiliates make any
                                  representation to any purchaser of
                                  Convertible Note PERQS as to the performance
                                  of Sepracor Stock or the Sepracor Notes.

                                  We and/or our subsidiaries may presently or
                                  from time to time engage in business with
                                  Sepracor, including extending loans to, or
                                  making equity investments in, Sepracor or
                                  providing advisory services to Sepracor,
                                  including merger and acquisition advisory
                                  services. In the course of such business, we
                                  or our affiliates may acquire non-public
                                  information with respect to Sepracor and, in
                                  addition, one or more of our affiliates may
                                  publish research reports with respect to
                                  Sepracor. The statement in the preceding
                                  sentence is not intended to affect the right
                                  of holders of the Convertible Note PERQS
                                  under the securities laws. As a prospective
                                  purchaser of Convertible Note PERQS, you
                                  should undertake an independent investigation
                                  of Sepracor and the terms of the Sepracor
                                  Notes and Sepracor Stock as in your judgment
                                  is appropriate to make an informed decision
                                  with respect to an investment in Sepracor
                                  Stock or the Sepracor Notes.

Historical Information.........   The following tables set forth the high and
                                  low Market Price of Sepracor Stock during
                                  1998, 1999 and during 2000 through September
                                  20, 2000 and the high and low mid-market
                                  prices of Sepracor Notes from September 8,
                                  1999 (the first date on which Bloomberg
                                  Generic Prices for the Sepracor Notes were
                                  made available) and during 2000 through
                                  September 20, 2000. The Market Price of
                                  Sepracor Stock on September 20, 2000 was $100
                                  3/8. The bid and ask prices of the Sepracor
                                  Notes on September 18, 2000 were $171.75 and
                                  $172.75. We obtained the Market Prices for
                                  Sepracor Stock and the prices of Sepracor
                                  Notes listed below from Bloomberg Financial
                                  Markets. The Sepracor Notes are not listed or
                                  traded on an exchange. Accordingly the prices
                                  at which sales of Sepracor Notes are made are
                                  not publicly available. The historical prices
                                  for the Sepracor Notes are the "Bloomberg
                                  Generic Prices (BGN)" calculated by Bloomberg
                                  by a proprietary process. The high and low
                                  prices listed below represent a mid-market
                                  price based on dealer prices contributed to
                                  Bloomberg Financial Markets. No
                                  representation is made that the Sepracor
                                  Notes could have been sold or purchased at
                                  the prices listed below. These prices may be
                                  materially different from the prices paid or
                                  received by us or our affiliates with respect
                                  to the Sepracor Notes over the periods
                                  described. You should not take


                                     PS-18
<PAGE>


                                  the historical prices of Sepracor Stock or
                                  the Sepracor Notes as an indication of future
                                  performance. The price of Sepracor Stock or
                                  the Sepracor Notes may decrease so that you
                                  will receive at maturity Sepracor Notes worth
                                  less than Issue Price of the Convertible Note
                                  PERQS. We cannot give you any assurance that
                                  the price of Sepracor Notes will increase so
                                  that at maturity you will receive Sepracor
                                  Notes worth more than the principal amount of
                                  the Convertible Note PERQS or that Final
                                  Parity will not exceed the Maximum Parity
                                  Amount, in which case you will receive less
                                  than one-half of a Sepracor Note in exchange
                                  for each Convertible Note PERQS at maturity.
                                  Because the Convertible Note PERQS are
                                  exchangeable at maturity for Sepracor Notes,
                                  there is no guaranteed return of your
                                  investment in the Convertible Note PERQS. To
                                  the extent that the value of Sepracor Notes
                                  drops below the Issue Price and the shortfall
                                  is not offset by the coupon paid on the
                                  Convertible Note PERQS, you will lose money
                                  on your investment.

                                      Sepracor Notes       High         Low
                                  ----------------------  ------       -----
                                  (Cusip # 817315AH7)
                                  1999
                                    Third Quarter
                                     (from September 8,
                                     1999)............... $ 94.54     $ 89.42
                                    Fourth Quarter....... $110.21     $ 90.13
                                  2000
                                    First Quarter........ $207.58     $103.53
                                    Second Quarter....... $206.80     $122.67
                                    Third Quarter
                                     (through September
                                     18, 2000)........... $228.83     $162.38

                                      Sepracor Notes       High         Low
                                  ----------------------  ------       -----
                                  (Cusip # 817315104)
                                  1998
                                    First Quarter........ $ 21 21/32  $ 17 9/16
                                    Second Quarter....... $ 23 3/8    $ 18 3/8
                                    Third Quarter  ...... $ 35 1/4    $ 21 3/8
                                    Fourth Quarter ...... $ 44 5/16   $ 26 1/2
                                  1999
                                    First Quarter........ $ 69 11/16  $ 44 15/16
                                    Second Quarter....... $ 60 1/16   $ 30
                                    Third Quarter........ $ 46 7/8    $ 32 11/16
                                    Fourth Quarter....... $ 53 1/2    $ 35 1/8
                                  2000
                                    First Quarter........ $124 3/8    $ 47 1/4
                                    Second Quarter....... $123        $ 67
                                    Third Quarter
                                      (through September
                                      20, 2000).........  $137 25/64  $ 93 3/64

                                  Historical prices of Sepracor Stock have been
                                  adjusted for a 2 for 1 stock split of
                                  Sepracor Stock, which became effective in the
                                  first quarter of 2000.


                                     PS-19
<PAGE>


                                  Sepracor has not paid cash dividends on
                                  Sepracor Stock to date. We make no
                                  representation as to the amount of dividends,
                                  if any, that Sepracor will pay in the future.
                                  In any event, as a holder of the Convertible
                                  Note PERQS, you will not be entitled to
                                  receive dividends, if any, that may be
                                  payable on Sepracor Stock.

Use of Proceeds and Hedging....   The net proceeds we receive from the sale of
                                  the Convertible Note PERQS will be used for
                                  general corporate purposes and, in part, by
                                  us or by one or more of our subsidiaries in
                                  connection with hedging our obligations under
                                  the Convertible Note PERQS. See also "Use of
                                  Proceeds" in the accompanying Prospectus.

                                  On or prior to the date of this pricing
                                  supplement, we, through our subsidiaries or
                                  others, will hedge our anticipated exposure
                                  in connection with the Convertible Note PERQS
                                  by taking positions in Sepracor Notes,
                                  Sepracor Stock and other instruments.
                                  Purchase activity could potentially increase
                                  the price of Sepracor Stock, and therefore
                                  effectively increase the level to which
                                  Sepracor Stock must rise before you would
                                  receive at maturity Sepracor Notes worth an
                                  amount that is equal to or greater than the
                                  principal amount of the Convertible Note
                                  PERQS. Through our subsidiaries, we are
                                  likely to modify our hedge position
                                  throughout the life of the Convertible Note
                                  PERQS, including on the Determination Date,
                                  by purchasing and selling Sepracor Notes,
                                  Sepracor Stock, options contracts on Sepracor
                                  Stock listed on major securities markets or
                                  sold over-the-counter or positions in any
                                  other instruments that we may wish to use in
                                  connection with such hedging. Although we
                                  have no reason to believe that our hedging
                                  activity will have a material impact on the
                                  price of the Sepracor Notes or Sepracor
                                  Stock, we cannot give any assurance that we
                                  will not affect such price as a result of our
                                  hedging activities.

Supplemental Information
  Concerning Plan of
  Distribution.................   In order to facilitate the offering of the
                                  Convertible Note PERQS, the Agent may engage
                                  in transactions that stabilize, maintain or
                                  otherwise affect the price of the Convertible
                                  Note PERQS, the Sepracor Notes or Sepracor
                                  Stock. Specifically, the Agent may overallot
                                  in connection with the offering, creating a
                                  short position in the Convertible Note PERQS
                                  for its own account. In addition, to cover
                                  allotments or to stabilize the price of the
                                  Convertible Note PERQS, the Agent may bid
                                  for, and purchase, the Convertible Note
                                  PERQS, the Sepracor Notes or Sepracor Stock
                                  in the open market. See "Use of Proceeds and
                                  Hedging" above.

                                  We have agreed to indemnify the Agent against
                                  certain liabilities, including liabilities
                                  under the Securities Act of 1933, as amended.
                                  See also "Plan of Distribution" in the
                                  accompanying Prospectus Supplement.

ERISA Matters for Pension
  Plans and Companies..........   Each fiduciary of a pension, profit-sharing
                                  or other employee benefit plan subject to the
                                  Employee Retirement Income Security Act of
                                  1974, as amended ("ERISA") (a "Plan"), should
                                  consider the fiduciary standards of ERISA in
                                  the context of the Plan's


                                     PS-20
<PAGE>


                                  particular circumstances before authorizing
                                  an investment in the Convertible Note PERQS.
                                  Accordingly, among other factors, the
                                  fiduciary should consider whether the
                                  investment would satisfy the prudence and
                                  diversification requirements of ERISA and
                                  would be consistent with the documents and
                                  instruments governing the Plan.

                                  In addition, we and certain of our
                                  subsidiaries and affiliates, including MS &
                                  Co. and Dean Witter Reynolds Inc. ("DWR"),
                                  are each considered a "party in interest"
                                  within the meaning of ERISA, or a
                                  "disqualified person" within the meaning of
                                  the Internal Revenue Code of 1986, as amended
                                  (the "Code") with respect to many Plans.
                                  Prohibited transactions within the meaning of
                                  ERISA or the Code would likely arise, for
                                  example, if the Convertible Note PERQS are
                                  acquired by or with the assets of a Plan with
                                  respect to which MS & Co., DWR or any of
                                  their affiliates is a service provider,
                                  unless the Convertible Note PERQS are
                                  acquired pursuant to an exemption from the
                                  "prohibited transaction"rules. A violation of
                                  these "prohibited transaction" rules may
                                  result in an excise tax or other liabilities
                                  under ERISA and/or Section 4975 of the Code
                                  for such persons, unless exemptive relief is
                                  available under an applicable statutory or
                                  administrative exemption.

                                  The U.S. Department of Labor has issued five
                                  prohibited transaction class exemptions
                                  ("PTCEs") that may provide exemptive relief
                                  for direct or indirect prohibited
                                  transactions resulting from the purchase or
                                  holding of the Convertible Note PERQS. Those
                                  class exemptions are PTCE 96-23 (for certain
                                  transactions determined by in-house asset
                                  managers), PTCE 95-60 (for certain
                                  transactions involving insurance company
                                  general accounts), PTCE 91-38 (for certain
                                  transactions involving bank collective
                                  investment funds), PTCE 90-1 (for certain
                                  transactions involving insurance company
                                  separate accounts), and PTCE 84-14 (for
                                  certain transactions determined by
                                  independent qualified asset managers).

                                  Because we are considered a party in interest
                                  with respect to many Plans, the Convertible
                                  Note PERQS may not be purchased or held by
                                  any Plan, any entity whose underlying assets
                                  include "plan assets" by reason of any Plan's
                                  investment in the entity (a "Plan Asset
                                  Entity") or any person investing "plan
                                  assets" of any Plan, unless such purchaser or
                                  holder is eligible for exemptive relief,
                                  including relief available under PTCE 96-23,
                                  95-60, 91-38, 90-1, or 84-14 or such purchase
                                  and holding is otherwise not prohibited. Any
                                  purchaser, including any fiduciary purchasing
                                  on behalf of a Plan, or holder of the
                                  Convertible Note PERQS will be deemed to have
                                  represented, in its corporate and fiduciary
                                  capacity, by its purchase and holding thereof
                                  that it either (a) is not a Plan or a Plan
                                  Asset Entity and is not purchasing such
                                  securities on behalf of or with "plan assets"
                                  of any Plan or (b) is eligible for exemptive
                                  relief or such purchase or holding is not
                                  prohibited by ERISA or Section 4975 of the
                                  Code.

                                  Under ERISA, assets of a Plan may include
                                  assets held in the general account of an
                                  insurance company which has issued an
                                  insurance policy to such plan or assets of an
                                  entity in which the


                                     PS-21
<PAGE>


                                  Plan has invested. Accordingly, insurance
                                  company general accounts that include assets
                                  of a Plan must ensure that one of the
                                  foregoing exemptions is available. Due to the
                                  complexity of these rules and the penalties
                                  that may be imposed upon persons involved in
                                  non-exempt prohibited transactions, it is
                                  particularly important that fiduciaries or
                                  other persons considering purchasing the
                                  Convertible Note PERQS on behalf of or with
                                  "plan assets" of any Plan consult with their
                                  counsel regarding the availability of
                                  exemptive relief under PTCE 96-23, 95-60,
                                  91-38, 90-1 or 84-14.

                                  Purchasers of the Convertible Note PERQS have
                                  exclusive responsibility for ensuring that
                                  their purchase and holding of the Convertible
                                  Note PERQS do not violate the prohibited
                                  transaction rules of ERISA or the Code.

United States Federal Income
  Taxation.....................   The following summary is based on the advice
                                  of Davis Polk & Wardwell, our special tax
                                  counsel ("Tax Counsel"), and is a general
                                  discussion of the principal potential U.S.
                                  federal income tax consequences to initial
                                  holders of the Convertible Note PERQS
                                  purchasing the Convertible Note PERQS at the
                                  Issue Price, who will hold the Convertible
                                  Note PERQS as capital assets within the
                                  meaning of Section 1221 of the Code. This
                                  summary is based on the Code, administrative
                                  pronouncements, judicial decisions and
                                  currently effective and proposed Treasury
                                  Regulations, changes to any of which
                                  subsequent to the date of this pricing
                                  supplement may affect the tax consequences
                                  described herein. This summary does not
                                  address all aspects of the U.S. federal
                                  income taxation that may be relevant to a
                                  particular holder in light of its individual
                                  circumstances or to certain types of holders
                                  subject to special treatment under the U.S.
                                  federal income tax laws (e.g., certain
                                  financial institutions, tax-exempt
                                  organizations, dealers in options or
                                  securities, or persons who hold Convertible
                                  Note PERQS as part of a hedging transaction,
                                  straddle, conversion or other integrated
                                  transaction). As the law applicable to the
                                  U.S. federal income taxation of instruments
                                  such as the Convertible Note PERQS is
                                  technical and complex, the discussion below
                                  necessarily represents only a general
                                  summary. Moreover, the effect of any
                                  applicable state, local or foreign tax laws
                                  is not discussed.

                                  General

                                  Pursuant to the terms of the Convertible Note
                                  PERQS, we and every holder of Convertible
                                  Note PERQS agree (in the absence of an
                                  administrative determination or judicial
                                  ruling to the contrary) to characterize
                                  Convertible Note PERQS for all tax purposes
                                  as an investment unit consisting of the
                                  following components (the "Components"): (i)
                                  a contract (the "Forward Contract") that
                                  requires the holder of the Convertible Note
                                  PERQS to purchase, and us to sell, for an
                                  amount equal to $   (the "Forward Price"), the
                                  Sepracor Notes at maturity, and (ii) a
                                  deposit with us of a fixed amount of cash,
                                  equal to the Issue Price, to secure the
                                  holder's obligation to purchase the Sepracor
                                  Notes (the "Deposit"), which Deposit bears an
                                  annual yield of   % per annum, which yield is
                                  based on our cost of borrowing. Under this
                                  characterization, less than the full periodic
                                  payments on the Convertible Note PERQS,


                                     PS-22
<PAGE>


                                  consisting of the semiannual Underlying
                                  Coupon payments and the quarterly
                                  Supplemental Coupon payments, will be
                                  attributable to the yield on the Deposit.
                                  Accordingly, the excess of the quarterly
                                  Supplemental Coupon payments on the
                                  Convertible Note PERQS over the portion of
                                  those payments attributable to the yield on
                                  the Deposit, in addition to the entire
                                  semiannual Underlying Coupon payments on the
                                  Convertible Note PERQS, will represent
                                  payments attributable to the holders' entry
                                  into the Forward Contract (the "Contract
                                  Fees"). Furthermore, based on our
                                  determination of the relative fair market
                                  values of the Components at the time of
                                  issuance of the Convertible Note PERQS, we
                                  will allocate 100% of the Issue Price of the
                                  Convertible Note PERQS to the Deposit and
                                  none to the Forward Contract.

                                  Our allocation of the Issue Price among the
                                  Components will be binding on a holder of the
                                  Convertible Note PERQS, unless such holder
                                  timely and explicitly discloses to the IRS
                                  that its allocation is different from ours.
                                  The treatment of the Convertible Note PERQS
                                  described above and our allocation are not,
                                  however, binding on the IRS or the courts. No
                                  statutory, judicial or administrative
                                  authority directly addresses the
                                  characterization of the Convertible Note
                                  PERQS or instruments similar to the
                                  Convertible Note PERQS for U.S. federal
                                  income tax purposes, and no ruling is being
                                  requested from the IRS with respect to the
                                  Convertible Note PERQS. Due to the absence of
                                  authorities that directly address instruments
                                  that are similar to the Convertible Note
                                  PERQS, Tax Counsel is unable to render an
                                  opinion as to the proper U.S. federal income
                                  tax characterization of the Convertible Note
                                  PERQS. As a result, significant aspects of
                                  the U.S. federal income tax consequences of
                                  an investment in the Convertible Note PERQS
                                  are not certain, and no assurance can be
                                  given that the IRS or the courts will agree
                                  with the characterization described herein.
                                  Accordingly, you are urged to consult your
                                  tax advisor regarding the U.S. federal income
                                  tax consequences of an investment in the
                                  Convertible Note PERQS (including alternative
                                  characterizations of the Convertible Note
                                  PERQS) and with respect to any tax
                                  consequences arising under the laws of any
                                  state, local or foreign taxing jurisdiction.
                                  Unless otherwise stated, the following
                                  discussion is based on the treatment and the
                                  allocation described above.

                                  Tax Treatment of the Convertible Note PERQS

                                  Assuming the characterization of the
                                  Convertible Note PERQS, the allocation of the
                                  periodic payments, and the allocation of the
                                  Issue Price as set forth above, Tax Counsel
                                  believes that the following U.S. federal
                                  income tax consequences should result.

                                  Periodic Payments on the Convertible Note
                                  PERQS. To the extent attributable to the
                                  interest on the Deposit, periodic payments on
                                  the Convertible Note PERQS will generally be
                                  taxable to a U.S. Holder as ordinary income
                                  at the time accrued or received in accordance
                                  with the U.S. Holder's method of accounting
                                  for U.S. federal income tax purposes.
                                  Although the federal income tax


                                     PS-23
<PAGE>


                                  treatment of the Contract Fees is uncertain,
                                  we intend to take the position that the
                                  Contract Fees constitute taxable income to
                                  the holders at the time accrued or received
                                  in accordance with the U.S. Holder's method
                                  of accounting for U.S. federal income tax
                                  purposes.

                                  Tax Basis. Based on our determination set
                                  forth above, the U.S. Holder's tax basis in
                                  the Forward Contract will be zero, and the
                                  U.S. Holder's tax basis in the Deposit will
                                  be 100% of the Issue Price.

                                  Settlement of the Forward Contract. Upon the
                                  maturity of the Forward Contract, a U.S.
                                  Holder would, pursuant to the Forward
                                  Contract, be deemed to have applied the
                                  Forward Price toward the purchase of Sepracor
                                  Notes, and a U.S. Holder would not recognize
                                  any gain or loss with respect to any Sepracor
                                  Notes received thereon. With respect to any
                                  cash received upon maturity, a U.S. Holder
                                  would recognize gain or loss. The amount of
                                  such gain or loss would be the extent to
                                  which the amount of such cash received
                                  differs from the pro rata portion of the
                                  Forward Price allocable to the cash. Any such
                                  gain or loss would generally be capital gain
                                  or loss, as the case may be. With respect to
                                  any Sepracor Notes received upon maturity,
                                  the U.S. Holder would have an adjusted tax
                                  basis in such Sepracor Notes equal to the pro
                                  rata portion of the Forward Price allocable
                                  thereto. The allocation of the Forward Price
                                  between cash and Sepracor Notes should be
                                  based on the amount of the cash received and
                                  the relative fair market value, as of the
                                  maturity, of the Sepracor Notes. The U.S.
                                  Holder's holding period of any Sepracor Notes
                                  received would start on the day after the
                                  maturity of the Convertible Note PERQS.

                                  Sale or Exchange of the Convertible Note
                                  PERQS. Upon a sale or exchange of a
                                  Convertible Note PERQS prior to the maturity
                                  of the Convertible Note PERQS, a U.S. Holder
                                  would recognize taxable gain or loss equal to
                                  the difference between the amount realized on
                                  such sale or exchange and such U.S. Holder's
                                  tax basis in the Convertible Note PERQS so
                                  sold or exchanged. Any such gain or loss
                                  would generally be capital gain or loss, as
                                  the case may be. Such U.S. Holder's tax basis
                                  in the Convertible Note PERQS would generally
                                  equal the U.S. Holder's tax basis in the
                                  Deposit. For these purposes, the amount
                                  realized does not include any amount
                                  attributable to accrued but unpaid interest
                                  payments on the Deposit, which would be taxed
                                  as described under "--Periodic Payments on
                                  the Convertible Note PERQS" above. It is
                                  uncertain whether the amount realized
                                  includes any amount attributable to accrued
                                  but unpaid Contract Fees. U.S. Holders should
                                  consult their tax advisors regarding the
                                  treatment of accrued but unpaid Contract Fees
                                  upon the sale or exchange of Convertible Note
                                  PERQS.

                                  Possible Alternative Tax Treatments of an
                                  Investment in the Convertible Note PERQS

                                  Due to the absence of authorities that
                                  directly address the proper characterization
                                  of the Convertible Note PERQS, no assurance
                                  can


                                     PS-24
<PAGE>


                                  be given that the IRS will accept, or that a
                                  court will uphold, the characterization and
                                  tax treatment described above. MSDW will take
                                  the position that the Convertible Note PERQS
                                  are not treated as a single debt instrument
                                  for tax purposes. If the IRS were successful
                                  in asserting that the Convertible Note PERQS
                                  are a single debt instrument for tax
                                  purposes, the timing and character of income
                                  thereon could be affected. Other alternative
                                  federal income tax characterizations or
                                  treatments of the Convertible Note PERQS are
                                  also possible and, if applied, could also
                                  affect the timing and the character of the
                                  income or loss with respect to the
                                  Convertible Note PERQS. It is possible, for
                                  example, that Convertible Note PERQS could be
                                  treated as constituting a prepaid forward
                                  contract or a combination of a prepaid
                                  forward contract and one or more options.
                                  Other alternative characterizations are also
                                  possible. Accordingly, prospective purchasers
                                  are urged to consult their tax advisors
                                  regarding the U.S. federal income tax
                                  consequences of an investment in the
                                  Convertible Note PERQS.

                                  Backup Withholding and Information Reporting

                                  A U.S. Holder of Convertible Note PERQS may
                                  be subject to information reporting and to
                                  backup withholding at a rate of 31 percent of
                                  the amounts paid to the U.S. Holder, unless
                                  such U.S. Holder provides proof of an
                                  applicable exemption or a correct taxpayer
                                  identification number and otherwise complies
                                  with applicable requirements of the backup
                                  withholding rules. The amounts withheld under
                                  the backup withholding rules are not an
                                  additional tax and may be refunded, or
                                  credited against the U.S. Holder's U.S.
                                  federal income tax liability, provided the
                                  required information is furnished to the IRS.


                                     PS-25


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