MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST, N-30D, 1999-11-29

MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
N-30D, 1999-11-29

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<PAGE>

MORGAN STANLEY
DEAN WITTER
CONVERTIBLE
SECURITIES TRUST

[PHOTO]

ANNUAL REPORT
SEPTEMBER 30, 1999

<PAGE>

<TABLE>
<S> <C>
MORGAN STANLEY DEAN WITTER CONVERTIBLE TWO WORLD TRADE CENTER,
SECURITIES TRUST NEW YORK, NEW YORK 10048
LETTER TO THE SHAREHOLDERS SEPTEMBER 30, 1999
</TABLE>

DEAR SHAREHOLDER:

During the twelve-month period ended September 30, 1999, the U.S. equity markets
fluctuated substantially, achieving record highs before settling into a trading
range near the end of September. The Standard & Poor's 500 Composite Stock Price
Index (S&P 500) gained 27.79 percent during the period as the contradictory
forces of a budding global upturn and domestic fears of higher interest rates
and inflation converged upon the market. Commodity prices climbed, wage
settlements rose and consumer demand continued unabated, yet inflation remained
tame. Against this backdrop, the Federal Reserve Board reversed its monetary
policy during the summer and raised the federal-funds rate in two steps, to 5.25
percent.

The convertible market outperformed that of equities over the fiscal year,
boosted by the income component and downside protection offered by convertible
securities. Strength in the technology and telecommunications sectors, which
together make up a large part of the convertible universe, also aided relative
performance.

PERFORMANCE AND PORTFOLIO

For the twelve-month period ended September 30, 1999, Morgan Stanley Dean Witter
Convertible Securities Trust's Class B shares posted a total return of 14.62
percent compared to 21.36 percent for the Goldman Sachs Convertible 100 Index
and 21.00 percent for the Lipper Convertible Securities Fund average. During the
same period, the Fund's Class A, C and D shares returned 15.64 percent, 14.83
percent and 15.81 percent, respectively. The performance of the Fund's four
share classes varies because of differing expenses. The accompanying chart
compares the Fund's performance to that of the Lipper and Goldman Sachs indexes.
(The total return figures shown assume the reinvestment of all distributions and
do not reflect the deduction of any applicable sales charges.)

<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE
SECURITIES TRUST
LETTER TO THE SHAREHOLDERS SEPTEMBER 30, 1999, CONTINUED

The Fund's underperformance of its benchmark indexes can be attributed to its
focus on small-cap issues. With the exception of April and May, large caps
significantly outperformed small caps during the fiscal year as illiquidity and
Y2K-related credit concerns reduced investor's appetites for smaller issues.
Contributing positively to overall Fund performance was a heavy exposure to the
telecommunications sector.

The Fund uses a value-oriented, bottom-up approach to evaluate potential
investments, focusing on companies and industries with strong underlying
fundamentals and solid long-term growth potential. We invest primarily in
convertible securities issued by small- and medium-capitalization companies that
we believe offer excellent participation in a rising equity market and downside
protection in a declining market. The Fund has recently increased its holdings
in large-cap convertibles to provide better credit stability and greater equity
participation where underlying equity fundamentals are attractive. As of
September 30, 1999, the Fund's portfolio held approximately 58 industries.

LOOKING AHEAD

We believe that the convertible market overall, and the small-cap convertible
market in particular, remain attractive, and that the Fund's increased holdings
of larger names should benefit it in difficult credit environments and provide
broader participation in equity markets. We believe that convertibles can
perform well over the long term, offering potentially competitive returns in
modestly increasing, stable or declining equity markets, though they may tend to
lag equities during very strong periods.

We appreciate your ongoing support of Morgan Stanley Dean Witter Convertible
Securities Trust and look forward to continuing to serve your investment needs.

Very truly yours,

/s/ Charles A. Fiumefreddo
CHARLES A. FIUMEFREDDO
CHAIRMAN OF THE BOARD

/s/ Mitchell M. Merin
MITCHELL M. MERIN
PRESIDENT

2
<PAGE>

<TABLE>
<S> <C>
MORGAN STANLEY DEAN WITTER CONVERTIBLE
SECURITIES TRUST
FUND PERFORMANCE SEPTEMBER 30, 1999
</TABLE>

EDGAR REPRESENTATION OF DATA POINTS USED IN PRINTED GRAPHIC

<TABLE>
<CAPTION>
GROWTH OF $10,000 -- CLASS B SHARES FUND GOLDMAN LIPPER (5)
($ IN THOUSANDS) SACHS (4)
<S> <C> <C> <C>
September 1989 $10,000 $10,000 $10,000
September 1990 $8,307 $8,487 $8,871
September 1991 $9,880 $10,666 $11,407
September 1992 $10,441 $12,586 $12,965
September 1993 $12,866 $14,923 $15,708
September 1994 $13,512 $15,283 $15,690
September 1995 $15,360 $18,166 $18,173
September 1996 $17,619 $20,711 $20,640
September 1997 $21,739 $25,843 $25,765
September 1998 $18,692 $23,918 $23,977
September 1999 $21,425(3) $29,028 $29,013
</TABLE>

PAST PERFORMANCE IS NOT PREDICTIVE OF FUTURE RETURNS. PERFORMANCE FOR
CLASS A, CLASS C, AND CLASS D SHARES WILL VARY FROM THE PERFORMANCE OF
CLASS B SHARES SHOWN ABOVE DUE TO DIFFERENCES IN SALES CHARGES AND EXPENSES.

<TABLE>
<CAPTION>
AVERAGE ANNUAL TOTAL RETURNS
-----------------------------------------------------------------------------------------------------------------------------
CLASS B SHARES* CLASS A SHARES+
----------------------------------------------------------- -----------------------------------------------------------
<S> <C> <C> <C> <C> <C>
1 Year 14.62%(1) 9.62%(2) 1 Year 15.64%(1) 9.57%(2)
5 Years 9.66 (1) 9.38 (2) Since Inception (7/28/97) 2.97%(1) 0.45%(2)
10 Years 7.92 (1) 7.92 (2)
</TABLE>

<TABLE>
<CAPTION>
CLASS C SHARES++ CLASS D SHARES#
----------------------------------------------------------- -----------------------------------------------------------
<S> <C> <C> <C> <C> <C>
1 Year 14.83%(1) 13.83%(2) 1 Year 15.81%(1)
Since Inception (7/28/97) 2.20%(1) 2.20%(2) Since Inception (7/28/97) 3.16%(1)
</TABLE>

- ------------------------
(1) Figure shown assumes reinvestment of all distributions and does not reflect
the deduction of any sales charges.
(2) Figure shown assumes reinvestment of all distributions and the deduction of
the maximum applicable sales charge. See the Fund's current prospectus for
complete details on fees and sales charges.
(3) Closing value assuming a complete redemption on September 30, 1999.
(4) The Goldman Sachs Convertible 100 Index tracks the performance of 100
equally weighted convertible issues with market capitalizations of at least
$100 million. The Index does not include any expenses, fees or charges. The
Index is unmanaged and should not be considered an investment.
(5) The Lipper Convertible Securities Funds Average tracks the performance of
the funds which primarily invest in convertible bonds and convertible
preferred shares of common stock as reported by Lipper.
* The maximum CDSC for Class B is 5.0%. The CDSC declines to 0% after six
years.
+ The maximum front-end sales charge for Class A is 5.25%.
++ The maximum CDSC for Class C shares is 1% for shares redeemed within one
year of purchase.
# Class D shares have no sales charge.

3
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999

<TABLE>
PRINCIPAL
AMOUNT IN COUPON MATURITY
THOUSANDS RATE DATE VALUE
- ---------------------------------------------------------------------------------------------------------------------------
<C> <S> <C> <C> <C>
CONVERTIBLE BONDS (50.6%)
ADVERTISING (1.8%)
$ 250 Doubleclick Inc. - 144A**...................................................... 4.75% 03/15/06 $ 388,477
2,000 Interpublic Group Co., Inc. - 144A**........................................... 1.87 06/01/06 1,848,800
1,500 Lamar Advertising Co........................................................... 5.25 09/15/06 1,890,375
------------
4,127,652
------------
AEROSPACE (1.3%)
4,000 Spacehab, Inc. - 144A**........................................................ 8.00 10/15/07 3,012,480
------------
ASSISTED LIVING SERVICES (0.6%)
2,540 Emeritus Corp. - 144A**........................................................ 6.25 01/01/06 1,447,800
------------
AUTO PARTS: O.E.M. (2.0%)
5,750 MascoTech, Inc................................................................. 4.50 12/15/03 4,607,188
------------
BIOTECHNOLOGY (1.7%)
3,000 Centocor Inc................................................................... 4.75 02/15/05 3,926,520
------------
BROADCASTING (3.0%)
5,000 Scandinavian Broadcasting System SA (Luxembourg)............................... 7.00 12/01/04 7,069,850
------------
CATALOG/SPECIALTY DISTRIBUTION (1.4%)
2,750 Amazon.com, Inc................................................................ 4.75 02/01/09 3,234,275
------------
CELLULAR TELEPHONE (1.3%)
4,770 U.S. Cellular Corp............................................................. 0.00 06/15/15 3,122,633
------------
CLOTHING/SHOE/ACCESSORY STORES (1.2%)
3,200 Genesco Inc.................................................................... 5.50 04/15/05 2,782,368
------------
COMPUTER SOFTWARE (2.9%)
5,000 Citrix Systems, Inc. - 144A**.................................................. 0.00 03/22/19 2,411,700
8,000 Network Associates, Inc........................................................ 0.00 02/13/18 2,575,440
2,000 Siebel Systems Inc. - 144A**................................................... 5.50 09/15/06 1,960,080
------------
6,947,220
------------
CONTRACT DRILLING (1.3%)
9,000 Pride International, Inc....................................................... 0.00 04/24/18 3,060,090
------------
DISCOUNT CHAINS (1.1%)
3,000 Costco Wholesale Corp.......................................................... 0.00 08/19/17 2,602,560
------------
DIVERSIFIED COMMERCIAL SERVICES (1.0%)
3,500 Metamor Worldwide, Inc......................................................... 2.94 08/15/04 2,364,740
------------
E.D.P. PERIPHERALS (0.5%)
1,500 Quantum Corp................................................................... 7.00 08/01/04 1,288,530
------------
E.D.P. SERVICES (1.2%)
2,500 May & Speh, Inc................................................................ 5.25 04/01/03 2,949,150
------------
ELECTRONIC COMPONENTS (1.4%)
3,000 Sanmina Corp. - 144A**......................................................... 4.25 05/01/04 3,342,900
------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
4
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

<TABLE>
PRINCIPAL
AMOUNT IN COUPON MATURITY
THOUSANDS RATE DATE VALUE
- ---------------------------------------------------------------------------------------------------------------------------
<C> <S> <C> <C> <C>
ELECTRONIC PRODUCTION EQUIPMENT (1.6%)
$ 2,500 Integrated Process Equipment Corp.............................................. 6.25% 09/15/04 $ 1,768,450
2,000 Lam Research Corp.............................................................. 5.00 09/01/02 1,983,480
------------
3,751,930
------------
ENGINEERING & CONSTRUCTION (1.5%)
4,000 Emcor Group, Inc............................................................... 5.75 04/01/05 3,595,440
------------
FOOD CHAINS (0.9%)
6,000 Whole Foods Market Inc......................................................... 0.00 03/02/18 2,006,100
------------
GENERIC DRUGS (1.3%)
2,500 Alpharma Inc. - 144A**......................................................... 3.00 06/01/06 3,003,125
------------
HOSPITAL/NURSING MANAGEMENT (0.3%)
2,500 ARV Assisted Living, Inc....................................................... 6.75 04/01/06 650,000
------------
HOTELS/RESORTS (0.5%)
5,000 Four Seasons Hotels, Inc. (Canada)............................................. 0.00 09/23/29 1,212,500
------------
INTERNET SERVICES (0.4%)
1,000 MindSpring Enterprises, Inc.................................................... 5.00 04/15/06 929,750
------------
INVESTMENT BANKERS/BROKERS/SERVICES (1.0%)
2,500 Merrill Lynch & Co............................................................. 0.25 05/10/06 2,305,550
------------
MAJOR U.S. TELECOMMUNICATIONS (3.2%)
2,500 Bell Atlantic Financial Service - 144A** (exchangeable into Cable & Wireless
Communications common stock)................................................. 4.25 09/15/05 2,620,000
5,000 Bell Atlantic Financial Service - 144A** (exchangeable into Telecom
Corporation of New Zealand common stock)..................................... 5.75 04/01/03 5,014,100
------------
7,634,100
------------
MEDICAL/NURSING SERVICES (0.9%)
2,000 Continucare Corp. - 144A** (a)................................................. 8.00 10/31/02 40,000
2,000 Greenery Rehabilitation Group, Inc............................................. 8.75 04/01/15 2,001,260
------------
2,041,260
------------
OTHER PHARMACEUTICALS (0.4%)
1,000 Sepracor Inc. - 144A**......................................................... 7.00 12/15/05 938,250
------------
OTHER TELECOMMUNICATIONS (4.1%)
3,000 Global Telesystems Group, Inc.................................................. 5.75 07/01/10 2,629,140
2,500 NTL Inc. - 144A**.............................................................. 7.00 12/15/08 4,234,675
1,750 SA Telecommunications, Inc. - 144A** (a)....................................... 10.00 08/15/06 52,500
3,000 Telefonos de Mexico S.A. (Mexico).............................................. 4.25 06/15/04 2,823,090
------------
9,739,405
------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
5
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

TOTAL CONVERTIBLE BONDS
(IDENTIFIED COST $121,716,837).................................................................... 119,112,941
------------
</TABLE>

<TABLE>
NUMBER OF
SHARES
- --------
<C> <S> <C>
CONVERTIBLE PREFERRED STOCKS (37.9%)
APPAREL (0.9%)
65,800 Warnaco Group, Inc. $3.00................................................................ 2,039,800
------------
AUTO PARTS: O.E.M. (0.0%)
120,000 BTI Capital Trust $3.25 - 144A** *....................................................... 60,000
------------
BIOTECHNOLOGY (1.1%)
20,000 Cephalon, Inc. $3.625 - 144A**........................................................... 1,115,000
63,500 Sicor Inc. $3.75......................................................................... 1,531,937
------------
2,646,937
------------
BROADCASTING (1.0%)
72,000 Sinclair Broadcasting Group, Inc. (Series D) $3.00....................................... 2,322,000
------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
6
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

<TABLE>
NUMBER OF
SHARES VALUE
- ------------------------------------------------------------------------------------------------------------------
<C> <S> <C>
CABLE TELEVISION (3.0%)
10,000 Adelphia Communications Corp. (Series D) $11.00.......................................... $ 1,775,000
13,825 EchoStar Communications Corp. (Series C) $3.375.......................................... 5,156,725
------------
6,931,725
------------
CELLULAR TELEPHONE (1.0%)
25,000 Omnipoint Corp. $3.50.................................................................... 2,350,000
------------
COMPUTER SOFTWARE (2.2%)
51,000 Microsoft Corp. (Series A) $2.197........................................................ 5,135,062
------------
CONTAINERS/PACKAGING (0.5%)
25,000 Sealed Air Corp. (Series A) $2.00........................................................ 1,268,750
------------
ELECTRIC UTILITIES (0.6%)
41,000 CMS Energy Corp. $3.63................................................................... 1,499,063
------------
FOOD DISTRIBUTORS (0.9%)
60,000 Suiza Capital Trust II $2.75............................................................. 2,118,300
------------
HOME BUILDING (0.5%)
35,000 Fleetwood Capital Trust $3.00............................................................ 1,228,675
------------
HOME FURNISHINGS (0.7%)
40,800 Newell Financial Trust I $2.625.......................................................... 1,689,161
------------
INDUSTRIAL SPECIALTIES (1.1%)
50,000 International Paper Capital Trust $2.625................................................. 2,539,500
------------
INTEGRATED OIL COMPANIES (0.9%)
40,000 Unocal Corp. $3.125...................................................................... 2,167,520
------------
INTERNATIONAL BANKS (1.3%)
110,000 National Australia Bank, Ltd. $1.969 (Australia) (Units) ++.............................. 3,011,250
------------
INTERNET SERVICES (1.7%)
50,000 PSINet, Inc. (Series C) $3.375........................................................... 1,981,250
50,000 Verio, Inc. (Series A) - 144A** $3.375................................................... 2,050,000
------------
4,031,250
------------
MAJOR CHEMICALS (1.2%)
75,000 Monsanto Co. $2.60....................................................................... 2,700,000
------------
MEDICAL/DENTAL DISTRIBUTORS (0.5%)
30,000 Owens & Minor Trust I (Series A) $2.688.................................................. 1,050,690
------------
MILITARY/GOV'T/TECHNICAL (1.1%)
54,400 Loral Space & Communications Ltd. (Series C) $3.00 (Bermuda)............................. 2,638,400
------------
MOVIES/ENTERTAINMENT (1.1%)
109,000 Metromedia International Group, Inc. $3.625.............................................. 2,684,125
------------
MUTUAL FUNDS (0.7%)
75,000 Amdocs Automatic Common Exchange Securities $1.51........................................ 1,621,875
------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
7
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

<TABLE>
NUMBER OF
SHARES VALUE
- ------------------------------------------------------------------------------------------------------------------
<C> <S> <C>
NEWSPAPERS (1.0%)
20,000 Tribune Co. $3.14........................................................................ $ 2,385,000
------------
OIL & GAS PRODUCTION (2.9%)
120,000 Apache Corp. $2.015...................................................................... 4,800,000
35,000 Newfield Financial Trust I $3.25......................................................... 1,907,500
------------
6,707,500
------------
OIL/GAS TRANSMISSION (1.4%)
50,000 Coastal Corp. $1.66...................................................................... 1,303,125
40,000 El Paso Energy Capital Trust I $2.375.................................................... 2,095,000
------------
3,398,125
------------
OILFIELD SERVICES/EQUIPMENT (0.5%)
35,000 Weatherford International, Inc. $2.50.................................................... 1,271,095
------------
OTHER CONSUMER SERVICES (1.0%)
80,000 Cendant Corp. $3.75...................................................................... 2,325,000
------------
OTHER TELECOMMUNICATIONS (1.6%)
40,000 SkyTel Communications, Inc. $2.25........................................................ 1,495,000
50,000 Winstar Communications, Inc. (Series D) $3.50............................................ 2,306,250
------------
3,801,250
------------
RAILROADS (1.6%)
25,000 Canadian National Railway Co. $2.625 (Canada)............................................ 1,292,188
52,400 Union Pacific Capital Trust $3.125....................................................... 2,362,506
------------
3,654,694
------------
REAL ESTATE INVESTMENT TRUSTS (2.5%)
80,000 Equity Office Properties Trust (Series B) $2.625 - 144A**................................ 3,160,000
65,064 FelCor Lodging Trust, Inc. (Series A) $1.95.............................................. 1,081,689
85,000 Reckson Associates Reality Corp. (Series A) $1.906....................................... 1,715,938
------------
5,957,627
------------
RENTAL/LEASING COMPANIES (1.1%)
70,000 United Rentals Trust I $3.25............................................................. 2,587,830
------------
SAVINGS & LOAN ASSOCIATIONS (0.4%)
20,000 Bank United Corp. $4.00.................................................................. 900,000
------------
SPECIALTY CHEMICALS (0.7%)
2,000 Hercules Trust II $65.00 (Units)++....................................................... 1,690,000
------------
TELECOMMUNICATIONS EQUIPMENT (0.4%)
3,800 Qualcomm Financial Trust $2.875.......................................................... 1,004,982
------------
TOOLS/HARDWARE (0.8%)
40,000 Seagrams Co., Ltd. $3.76 (Canada)........................................................ 1,857,500
------------

TOTAL CONVERTIBLE PREFERRED STOCKS
(IDENTIFIED COST $100,051,110)........................................................... 89,274,686
------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
8
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

<TABLE>
NUMBER OF
SHARES VALUE
- ------------------------------------------------------------------------------------------------------------------
<C> <S> <C>
COMMON STOCKS (1.2%)
APPAREL (0.7%)
85,000 Tropical Sportswear International Corp.*................................................. $ 1,583,125
------------
CASINO/GAMBLING (0.5%)
144,285 Alliance Gaming Corp.*................................................................... 1,118,209
------------
OTHER TELECOMMUNICATIONS (0.0%)
818 WinStar Communications, Inc.*............................................................ 32,106
------------

TOTAL COMMON STOCKS
(IDENTIFIED COST $2,861,170)............................................................. 2,733,440
------------
</TABLE>

<TABLE>
PRINCIPAL
AMOUNT IN COUPON MATURITY
THOUSANDS RATE DATE
- -------- -------- --------
<C> <S> <C> <C> <C>
SHORT-TERM INVESTMENTS (9.4%)
U.S. GOVERNMENT AGENCIES (b) (5.3%)
$ 4,000 Federal National Mortgage Assoc................................................ 5.15% 10/05/99 3,997,711
8,500 Tennessee Valley Authority..................................................... 5.18 10/12/99 8,486,547
------------
12,484,258
------------

TOTAL U.S. GOVERNMENT AGENCIES
(AMORTIZED COST $12,484,258)....................................................................... 12,484,258
------------

REPURCHASE AGREEMENT (4.1%)
9,746 The Bank of New York (dated 09/30/99; proceeds $9,747,826) (c) (IDENTIFIED COST
$9,746,472).................................................................. 5.00 10/01/99 9,746,472
------------

TOTAL SHORT-TERM INVESTMENTS
(IDENTIFIED COST $22,230,730)...................................................................... 22,230,730
------------
</TABLE>

<TABLE>
<S> <C> <C>
TOTAL INVESTMENTS
(IDENTIFIED COST $246,859,847) (d)........................................................ 99.1% 233,351,797

CASH AND OTHER ASSETS IN EXCESS OF LIABILITIES............................................ 0.9 2,169,732
----- -------------

NET ASSETS................................................................................ 100.0% $ 235,521,529
----- -------------
----- -------------
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
9
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
PORTFOLIO OF INVESTMENTS SEPTEMBER 30, 1999, CONTINUED

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

* Non-income producing security.
** Resale is restricted to qualified institutional investors.
++ Consists of more than one class of securities traded together as a unit;
stocks with attached warrants.
(a) Non-income producing security; bond in default.
(b) Securities were purchased on a discount basis. The interest rates shown
have been adjusted to reflect a money market equivalent yield.
(c) Collateralized by $9,962,430 U.S. Treasury Note 5.375% due 06/30/03 valued
at $9,945,300.
(d) The aggregate cost for federal income tax purposes approximates identified
cost. The aggregate gross unrealized appreciation is $19,240,274 and the
aggregate gross unrealized depreciation is $32,748,324, resulting in net
unrealized depreciation of $13,508,050.

SEE NOTES TO FINANCIAL STATEMENTS
10
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL STATEMENTS

STATEMENT OF ASSETS AND LIABILITIES
SEPTEMBER 30, 1999

<TABLE>
<S> <C>
ASSETS:
Investments in securities, at value
(identified cost $246,859,847)........................ $ 233,351,797
Receivable for:
Investments sold.................................... 5,184,995
Interest............................................ 1,716,459
Dividends........................................... 279,288
Shares of beneficial interest sold.................. 110,000
Prepaid expenses and other assets....................... 63,350
-------------
TOTAL ASSETS....................................... 240,705,889
-------------
LIABILITIES:
Payable for:
Investments purchased............................... 4,565,400
Plan of distribution fee............................ 197,656
Shares of beneficial interest repurchased........... 185,272
Investment management fee........................... 119,044
Accrued expenses and other payables..................... 116,988
-------------
TOTAL LIABILITIES.................................. 5,184,360
-------------
NET ASSETS......................................... $ 235,521,529
=============
COMPOSITION OF NET ASSETS:
Paid-in-capital......................................... $ 315,359,050
Net unrealized depreciation............................. (13,508,050)
Accumulated undistributed net investment income......... 6,220,842
Accumulated net realized loss........................... (72,550,313)
-------------
NET ASSETS......................................... $ 235,521,529
=============
CLASS A SHARES:
Net Assets.............................................. $1,123,884
Shares Outstanding (UNLIMITED AUTHORIZED, $.01 PAR
VALUE)................................................ 82,810
NET ASSET VALUE PER SHARE.......................... $13.57
=============
MAXIMUM OFFERING PRICE PER SHARE,
(NET ASSET VALUE PLUS 5.54% OF NET
ASSET VALUE)..................................... $14.32
=============
CLASS B SHARES:
Net Assets.............................................. $231,510,363
Shares Outstanding (UNLIMITED AUTHORIZED, $.01 PAR
VALUE)................................................ 17,054,429
NET ASSET VALUE PER SHARE.......................... $13.57
=============
CLASS C SHARES:
Net Assets.............................................. $2,868,912
Shares Outstanding (UNLIMITED AUTHORIZED, $.01 PAR
VALUE)................................................ 211,873
NET ASSET VALUE PER SHARE.......................... $13.54
=============
CLASS D SHARES:
Net Assets.............................................. $18,370
Shares Outstanding (UNLIMITED AUTHORIZED, $.01 PAR
VALUE)................................................ 1,354
NET ASSET VALUE PER SHARE.......................... $13.57
=============
</TABLE>

STATEMENT OF OPERATIONS
FOR THE YEAR ENDED SEPTEMBER 30, 1999

<TABLE>
<S> <C>
NET INVESTMENT INCOME:

INCOME
Dividends.................................................. $ 6,307,445
Interest................................................... 10,077,045
-----------

TOTAL INCOME.......................................... 16,384,490
-----------

EXPENSES
Plan of distribution fee (Class A shares).................. 2,637
Plan of distribution fee (Class B shares).................. 2,519,362
Plan of distribution fee (Class C shares).................. 24,859
Investment management fee.................................. 1,543,719
Transfer agent fees and expenses........................... 372,519
Professional fees.......................................... 82,732
Shareholder reports and notices............................ 76,600
Registration fees.......................................... 72,418
Custodian fees............................................. 21,375
Trustees' fees and expenses................................ 18,753
Other...................................................... 7,248
-----------

TOTAL EXPENSES........................................ 4,742,222
-----------

NET INVESTMENT INCOME................................. 11,642,268
-----------

NET REALIZED AND UNREALIZED GAIN (LOSS):
Net realized loss.......................................... (8,530,348)
Net change in unrealized depreciation...................... 32,992,426
-----------

NET GAIN.............................................. 24,462,078
-----------

NET INCREASE............................................... $36,104,346
===========
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
11
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL STATEMENTS, CONTINUED

STATEMENT OF CHANGES IN NET ASSETS

<TABLE>
FOR THE YEAR FOR THE YEAR
ENDED ENDED
SEPTEMBER 30, SEPTEMBER 30,
1999 1998
- ---------------------------------------------------------------------------------
<S> <C> <C>

INCREASE (DECREASE) IN NET ASSETS:

OPERATIONS:
Net investment income......................... $ 11,642,268 $ 14,325,883
Net realized gain (loss)...................... (8,530,348) 7,466,716
Net change in unrealized
appreciation/depreciation................... 32,992,426 (67,299,872)
------------ ------------

NET INCREASE (DECREASE).................. 36,104,346 (45,507,273)
------------ ------------

DIVIDENDS TO SHAREHOLDERS FROM NET INVESTMENT
INCOME:
Class A shares............................. (66,995) (35,198)
Class B shares............................. (12,469,366) (12,386,068)
Class C shares............................. (147,630) (89,566)
Class D shares............................. (64,653) (116,323)
------------ ------------

TOTAL DIVIDENDS.......................... (12,748,644) (12,627,155)
------------ ------------
Net increase (decrease) from transactions in
shares of beneficial interest............... (56,326,246) 9,302,728
------------ ------------

NET DECREASE............................. (32,970,544) (48,831,700)

NET ASSETS:
Beginning of period........................... 268,492,073 317,323,773
------------ ------------

END OF PERIOD
(INCLUDING UNDISTRIBUTED NET INVESTMENT
INCOME OF $6,220,842 AND $7,406,854,
RESPECTIVELY)............................. $235,521,529 $268,492,073
============ ============
</TABLE>

SEE NOTES TO FINANCIAL STATEMENTS
12
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999

1. ORGANIZATION AND ACCOUNTING POLICIES

Morgan Stanley Dean Witter Convertible Securities Trust (the "Fund") is
registered under the Investment Company Act of 1940, as amended (the "Act"), as
a diversified, open-end management investment company. The Fund's investment
objective is to seek a high level of total return on its assets through a
combination of current income and capital appreciation. The Fund was organized
as a Massachusetts business trust on May 21, 1985 and commenced operations on
October 31, 1985. On July 28, 1997, the Fund converted to a multiple class share
structure.

The Fund offers Class A shares, Class B shares, Class C shares and Class D
shares. The four classes are substantially the same except that most Class A
shares are subject to a sales charge imposed at the time of purchase and some
Class A shares, and most Class B shares and Class C shares are subject to a
contingent deferred sales charge imposed on shares redeemed within one year, six
years and one year, respectively. Class D shares are not subject to a sales
charge. Additionally, Class A shares, Class B shares and Class C shares incur
distribution expenses.

The preparation of financial statements in accordance with generally accepted
accounting principles requires management to make estimates and assumptions that
affect the reported amounts and disclosures. Actual results could differ from
those estimates.

The following is a summary of significant accounting policies:

A. VALUATION OF INVESTMENTS -- (1) an equity security listed or traded on the
New York, American or other domestic or foreign stock exchange is valued at its
latest sale price on that exchange prior to the time when assets are valued; if
there were no sales that day, the security is valued at the latest bid price (in
cases where a security is traded on more than one exchange, the security is
valued on the exchange designated as the primary market pursuant to procedures
adopted by the Trustees); (2) all other portfolio securities for which
over-the-counter market quotations are readily available are valued at the
latest available bid price prior to the time of valuation; (3) when market
quotations are not readily available, including circumstances under which it is
determined by Morgan Stanley Dean Witter Advisors Inc. (the "Investment
Manager") that sale and bid prices are not reflective of a security's market
value, portfolio securities are valued at their fair value as determined in good
faith under procedures established by and under the general supervision of the
Trustees (valuation of debt securities for which market quotations are not
readily available may be based upon current market prices of securities which
are comparable in coupon, rating and maturity or an appropriate matrix utilizing
similar factors); (4) certain portfolio securities may be valued by an outside
pricing service

13
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999, CONTINUED

approved by the Trustees. The pricing service may utilize a matrix system
incorporating security quality, maturity and coupon as the evaluation model
parameters, and/or research and evaluations by its staff, including review of
broker-dealer market price quotations, if available, in determining what it
believes is the fair valuation of the portfolio securities valued by such
pricing service; and (5) short-term debt securities having a maturity date of
more than sixty days at time of purchase are valued on a mark-to-market basis
until sixty days prior to maturity and thereafter at amortized cost based on
their value on the 61st day. Short-term debt securities having a maturity date
of sixty days or less at the time of purchase are valued at amortized cost.

B. ACCOUNTING FOR INVESTMENTS -- Security transactions are accounted for on the
trade date (date the order to buy or sell is executed). Realized gains and
losses on security transactions are determined by the identified cost method.
Dividend income and other distributions are recorded on the ex-dividend date.
Discounts are accreted over the life of the respective securities. Interest
income is accrued daily.

C. MULTIPLE CLASS ALLOCATIONS -- Investment income, expenses (other than
distribution fees), and realized and unrealized gains and losses are allocated
to each class of shares based upon the relative net asset value on the date such
items are recognized. Distribution fees are charged directly to the respective
class.

D. FEDERAL INCOME TAX STATUS -- It is the Fund's policy to comply with the
requirements of the Internal Revenue Code applicable to regulated investment
companies and to distribute all of its taxable income to its shareholders.
Accordingly, no federal income tax provision is required.

E. DIVIDENDS AND DISTRIBUTIONS TO SHAREHOLDERS -- The Fund records dividends and
distributions to its shareholders on the record date. The amount of dividends
and distributions from net investment income and net realized capital gains are
determined in accordance with federal income tax regulations which may differ
from generally accepted accounting principles. These "book/tax" differences are
either considered temporary or permanent in nature. To the extent these
differences are permanent in nature, such amounts are reclassified within the
capital accounts based on their federal tax-basis treatment; temporary
differences do not require reclassification. Dividends and distributions which
exceed net investment income and net realized capital gains for financial
reporting purposes but not for tax purposes are reported as dividends in excess
of net investment

14
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999, CONTINUED

income or distributions in excess of net realized capital gains. To the extent
they exceed net investment income and net realized capital gains for tax
purposes, they are reported as distributions of paid-in-capital.

2. INVESTMENT MANAGEMENT AGREEMENT

Pursuant to an Investment Management Agreement with the Investment Manager, the
Fund pays the Investment Manager a management fee, accrued daily and payable
monthly, by applying the following annual rates to the Fund's net assets
determined as of the close of each business day: 0.60% to the portion of the
daily net assets not exceeding $750 million; 0.55% to the portion of the daily
net assets exceeding $750 million but not exceeding $1 billion; 0.50% to the
portion of daily net assets exceeding $1 billion but not exceeding $1.5 billion;
0.475% to the portion of daily net assets exceeding $1.5 billion but not
exceeding $2 billion; 0.45% to the portion of daily net assets exceeding $2
billion but not exceeding $3 billion; and 0.425% to the portion of daily net
assets exceeding $3 billion.

Under the terms of the Agreement, in addition to managing the Fund's
investments, the Investment Manager maintains certain of the Fund's books and
records and furnishes, at its own expense, office space, facilities, equipment,
clerical, bookkeeping and certain legal services and pays the salaries of all
personnel, including officers of the Fund who are employees of the Investment
Manager. The Investment Manager also bears the cost of telephone services, heat,
light, power and other utilities provided to the Fund.

3. PLAN OF DISTRIBUTION

Shares of the Fund are distributed by Morgan Stanley Dean Witter Distributors
Inc. (the "Distributor"), an affiliate of the Investment Manager. The Fund has
adopted a Plan of Distribution (the "Plan") pursuant to Rule 12b-1 under the
Act. The Plan provides that the Fund will pay the Distributor a fee which is
accrued daily and paid monthly at the following annual rates: (i) Class A - up
to 0.25% of the average daily net assets of Class A; (ii) Class B - 1.0% of the
lesser of: (a) the average daily aggregate gross sales of the Class B shares
since the inception of the Fund (not including reinvestment of dividend or
capital gain distributions) less the average daily aggregate net asset value of
the Class B shares redeemed since the Fund's inception upon which a contingent
deferred sales charge has been imposed or waived; or (b) the average daily net
assets of Class B; and (iii) Class C - up to 1.0% of the average daily net
assets of Class C. In the case of Class A shares, amounts paid under the Plan
are paid to the Distributor for services provided. In the case of

15
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999, CONTINUED

Class B and Class C shares, amounts paid under the Plan are paid to the
Distributor for (1) services provided and the expenses borne by it and others in
the distribution of the shares of these Classes, including the payment of
commissions for sales of these Classes and incentive compensation to, and
expenses of, Morgan Stanley Dean Witter Financial Advisors and others who engage
in or support distribution of the shares or who service shareholder accounts,
including overhead and telephone expenses; (2) printing and distribution of
prospectuses and reports used in connection with the offering of these shares to
other than current shareholders; and (3) preparation, printing and distribution
of sales literature and advertising materials. In addition, the Distributor may
utilize fees paid pursuant to the Plan, in the case of Class B shares, to
compensate Dean Witter Reynolds Inc. ("DWR"), an affiliate of the Investment
Manager and Distributor, and other selected broker-dealers for their opportunity
costs in advancing such amounts, which compensation would be in the form of a
carrying charge on any unreimbursed expenses.

In the case of Class B shares, provided that the Plan continues in effect, any
cumulative expenses incurred by the Distributor but not yet recovered may be
recovered through the payment of future distribution fees from the Fund pursuant
to the Plan and contingent deferred sales charges paid by investors upon
redemption of Class B shares. Although there is no legal obligation for the Fund
to pay expenses incurred in excess of payments made to the Distributor under the
Plan and the proceeds of contingent deferred sales charges paid by investors
upon redemption of shares, if for any reason the Plan is terminated, the
Trustees will consider at that time the manner in which to treat such expenses.
The Distributor has advised the Fund that such excess amounts, including
carrying charges, totaled $83,217,930 at September 30, 1999.

In the case of Class A shares and Class C shares, expenses incurred pursuant to
the Plan in any calendar year in excess of 0.25% or 1.0% of the average daily
net assets of Class A or Class C, respectively, will not be reimbursed by the
Fund through payments in any subsequent year, except that expenses representing
a gross sales credit to Morgan Stanley Dean Witter Financial Advisors or other
selected broker-dealer representatives may be reimbursed in the subsequent
calendar year. For the year ended September 30, 1999, the distribution fee was
accrued for Class A shares and Class C shares at the annual rate of 0.21% and
0.88%, respectively.

The Distributor has informed the Fund that for the year ended September 30,
1999, it received contingent deferred sales charges from certain redemptions of
the Fund's Class A shares, Class B

16
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999, CONTINUED

shares and Class C shares of $101, $367,482 and $898, respectively and received
$5,500 in front-end sales charges from sales of the Fund's Class A shares. The
respective shareholders pay such charges which are not an expense of the Fund.

4. SECURITY TRANSACTIONS AND TRANSACTIONS WITH AFFILIATES

The cost of purchases and proceeds from sales of portfolio securities, excluding
short-term investments, for the year ended September 30, 1999 aggregated
$203,639,410 and $263,191,116, respectively.

For the year ended September 30, 1999, the Fund incurred brokerage commissions
of $4,557 with DWR for portfolio transactions executed on behalf of the Fund.

For the year ended September 30, 1999, the Fund incurred brokerage commissions
of $1,500 with Morgan Stanley & Co., Inc., an affiliate of the Investment
Manager and Distributor, for portfolio transactions executed on behalf of the
Fund.

Morgan Stanley Dean Witter Trust FSB, an affiliate of the Investment Manager and
Distributor, is the Fund's transfer agent. At September 30, 1999, the Fund had
transfer agent fees and expenses payable of approximately $3,400.

The Fund has an unfunded noncontributory defined benefit pension plan covering
all independent Trustees of the Fund who will have served as independent
Trustees for at least five years at the time of retirement. Benefits under this
plan are based on years of service and compensation during the last five years
of service. Aggregate pension costs for the year ended September 30, 1999
included in Trustees' fees and expenses in the Statement of Operations amounted
to $5,840. At September 30, 1999, the Fund had an accrued pension liability of
$52,407 which is included in accrued expenses in the Statement of Assets and
Liabilities.

5. FEDERAL INCOME TAX STATUS

At September 30, 1999, the Fund had a net capital loss carryover of
approximately $65,250,000 of which $62,731,000 will be available through
September 30, 2000 and $2,519,00 will be available through September 30, 2007 to
offset future capital gains to the extent provided by regulations.

Capital losses incurred after October 31 ("post-October" losses) within the
taxable year are deemed to arise on the first business day of the Fund's next
taxable year. The Fund incurred and will elect to defer net capital losses of
approximately $7,244,000 during fiscal 1999.

17
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
NOTES TO FINANCIAL STATEMENTS SEPTEMBER 30, 1999, CONTINUED

As of September 30, 1999, the Fund had temporary book/tax differences primarily
attributable to post-October losses and permanent book/tax differences primarily
attributable to an expired capital loss carryover. To reflect reclassifications
arising from the permanent differences, paid-in-capital was charged $46,129,103,
accumulated undistributed net investment income was charged $79,636 and
accumulated net realized loss was credited $46,208,739.

6. SHARES OF BENEFICIAL INTEREST

Transactions in shares of beneficial interest were as follows:

<TABLE>
<CAPTION>
FOR THE YEAR FOR THE YEAR
ENDED ENDED
SEPTEMBER 30, 1999 SEPTEMBER 30, 1998
------------------------- -------------------------
SHARES AMOUNT SHARES AMOUNT
---------- ------------ ---------- ------------
<S> <C> <C> <C> <C>
CLASS A SHARES
Sold.................................................... 1,099,363 $ 15,391,161 92,001 $ 1,349,947
Reinvestment of dividends............................... 4,081 54,460 2,116 29,640
Redeemed................................................ (1,097,990) (15,399,963) (20,090) (277,904)
---------- ------------ ---------- ------------
Net increase - Class A.................................. 5,454 45,658 74,027 1,101,683
---------- ------------ ---------- ------------
CLASS B SHARES
Sold.................................................... 2,569,889 35,097,104 4,637,313 68,850,146
Reinvestment of dividends............................... 751,728 9,953,748 701,336 9,971,800
Redeemed................................................ (7,420,340) (99,844,911) (5,189,588) (75,033,986)
---------- ------------ ---------- ------------
Net increase (decrease) - Class B....................... (4,098,723) (54,794,059) 149,061 3,787,960
---------- ------------ ---------- ------------
CLASS C SHARES
Sold.................................................... 95,253 1,240,659 213,545 3,143,678
Reinvestment of dividends............................... 8,572 113,534 4,574 64,248
Redeemed................................................ (84,273) (1,108,464) (66,982) (917,694)
---------- ------------ ---------- ------------
Net increase - Class C.................................. 19,552 245,729 151,137 2,290,232
---------- ------------ ---------- ------------
CLASS D SHARES
Sold.................................................... 88,216 1,145,065 201,768 2,963,943
Reinvestment of dividends............................... 90 1,192 103 1,480
Redeemed................................................ (223,273) (2,969,831) (66,930) (842,570)
---------- ------------ ---------- ------------
Net increase (decrease) - Class D....................... (134,967) (1,823,574) 134,941 2,122,853
---------- ------------ ---------- ------------
Net increase (decrease) in Fund......................... (4,208,684) $(56,326,246) 509,166 $ 9,302,728
========== ============ ========== ============
</TABLE>

18
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL HIGHLIGHTS

Selected ratios and per share data for a share of beneficial interest
outstanding throughout each period:

<TABLE>
<CAPTION>
FOR THE PERIOD
FOR THE YEAR FOR THE YEAR JULY 28, 1997*
ENDED ENDED THROUGH
SEPTEMBER 30, 1999 SEPTEMBER 30, 1998 SEPTEMBER 30, 1997
- --------------------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C>
CLASS A SHARES++

SELECTED PER SHARE DATA:

Net asset value, beginning of period........................ $ 12.45 $ 15.07 $ 14.31
------- -------- --------

Income (loss) from investment operations:
Net investment income.................................... 0.72 0.75 0.13
Net realized and unrealized gain (loss).................. 1.18 (2.68) 0.78
------- -------- --------

Total income (loss) from investment operations.............. 1.90 (1.93) 0.91
------- -------- --------

Less dividends from net investment income................... (0.78) (0.69) (0.15)
------- -------- --------

Net asset value, end of period.............................. $ 13.57 $ 12.45 $ 15.07
======= ======== ========

TOTAL RETURN+............................................... 15.64% (13.38)% 6.40%(1)

RATIOS TO AVERAGE NET ASSETS:

Expenses.................................................... 1.06%(3) 1.05%(3) 1.15%(2)

Net investment income....................................... 5.31%(3) 5.16%(3) 5.03%(2)

SUPPLEMENTAL DATA:

Net assets, end of period, in thousands..................... $1,124 $963 $50

Portfolio turnover rate..................................... 87% 95% 182%
</TABLE>

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

* The date shares were first issued.
++ The per share amounts were computed using an average number of shares
outstanding during the period.
+ Does not reflect the deduction of sales charge. Calculated based on the net
asset value as of the last business day of the period.
(1) Not annualized.
(2) Annualized.
(3) Reflects overall Fund ratios for investment income and non-class specific
expenses.

SEE NOTES TO FINANCIAL STATEMENTS
19
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL HIGHLIGHTS, CONTINUED

<TABLE>
<CAPTION>
FOR THE YEAR ENDED SEPTEMBER 30
-----------------------------------------------------------------
1999++ 1998++ 1997*++ 1996 1995
- -------------------------------------------------------------------------------------------------------------------------------
<S> <C> <C> <C> <C> <C>
CLASS B SHARES

SELECTED PER SHARE DATA:

Net asset value, beginning of period........................ $12.45 $15.07 $12.72 $11.67 $10.75
-------- -------- -------- -------- --------

Income (loss) from investment operations:
Net investment income.................................... 0.61 0.65 0.60 0.55 0.60
Net realized and unrealized gain (loss).................. 1.18 (2.70) 2.31 1.12 0.82
-------- -------- -------- -------- --------

Total income (loss) from investment operations.............. 1.79 (2.05) 2.91 1.67 1.42
-------- -------- -------- -------- --------

Less dividends from net investment income................... (0.67) (0.57) (0.56) (0.62) (0.50)
-------- -------- -------- -------- --------

Net asset value, end of period.............................. $13.57 $12.45 $15.07 $12.72 $11.67
======== ======== ======== ======== ========

TOTAL RETURN+............................................... 14.62% (14.01)% 23.38% 14.70% 13.68%

RATIOS TO AVERAGE NET ASSETS:

Expenses.................................................... 1.85%(1) 1.81 %(1) 1.84% 1.89% 1.96%

Net investment income....................................... 4.52%(1) 4.40 %(1) 4.45% 4.78% 5.24%

SUPPLEMENTAL DATA:

Net assets, end of period, in thousands..................... $231,510 $263,443 $316,633 $234,334 $185,398

Portfolio turnover rate..................................... 87% 95 % 182% 171% 138%
</TABLE>

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

* Prior to July 28, 1997, the Fund issued one class of shares. All shares of
the Fund held prior to that date have been designated Class B shares.
++ The per share amounts were computed using an average number of shares
outstanding during the period.
+ Does not reflect the deduction of sales charge. Calculated based on the net
asset value as of the last business day of the period.
(1) Reflects overall Fund ratios for investment income and non-class specific
expenses.

SEE NOTES TO FINANCIAL STATEMENTS
20
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL HIGHLIGHTS, CONTINUED

SELECTED PER SHARE DATA:

Net asset value, beginning of period........................ $ 12.43 $ 15.06 $ 14.31
------- -------- --------

Income (loss) from investment operations:
Net investment income.................................... 0.63 0.64 0.12
Net realized and unrealized gain (loss).................. 1.17 (2.68) 0.77
------- -------- --------

Total income (loss) from investment operations.............. 1.80 (2.04) 0.89
------- -------- --------

Less dividends from net investment income................... (0.69) (0.59) (0.14)
------- -------- --------

Net asset value, end of period.............................. $ 13.54 $ 12.43 $ 15.06
======= ======== ========

TOTAL RETURN+............................................... 14.83% (14.07)% 6.26%(1)

RATIOS TO AVERAGE NET ASSETS:

Expenses.................................................... 1.73%(3) 1.81 %(3) 1.92%(2)

Net investment income....................................... 4.64%(3) 4.40 %(3) 4.52%(2)

SUPPLEMENTAL DATA:

Net assets, end of period, in thousands..................... $ 2,869 $ 2,390 $620

Portfolio turnover rate..................................... 87% 95 % 182%
</TABLE>

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

SEE NOTES TO FINANCIAL STATEMENTS
21
<PAGE>
MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST
FINANCIAL HIGHLIGHTS, CONTINUED

SELECTED PER SHARE DATA:

Net asset value, beginning of period........................ $12.44 $15.08 $14.31
------- -------- --------

Income (loss) from investment operations:
Net investment income.................................... 0.79 0.79 0.13
Net realized and unrealized gain (loss).................. 1.15 (2.71) 0.80
------- -------- --------

Total income (loss) from investment operations.............. 1.94 (1.92) 0.93
------- -------- --------

Less dividends from net investment income................... (0.81) (0.72) (0.16)
------- -------- --------

Net asset value, end of period.............................. $13.57 $12.44 $15.08
======= ======== ========

TOTAL RETURN+............................................... 15.81% (13.19)% 6.42%(1)

RATIOS TO AVERAGE NET ASSETS:

Expenses.................................................... 0.85%(3) 0.81 %(3) 0.89%(2)

Net investment income....................................... 5.52%(3) 5.40 %(3) 4.94%(2)

SUPPLEMENTAL DATA:

Net assets, end of period, in thousands..................... $18 $1,696 $21

Portfolio turnover rate..................................... 87% 95 % 182%
</TABLE>

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

* The date shares were first issued.
++ The per share amounts were computed using an average number of shares
outstanding during the period.
+ Calculated based on the net asset value as of the last business day of the
period.
(1) Not annualized.
(2) Annualized.
(3) Reflects overall Fund ratios for investment income and non-class specific
expenses.

SEE NOTES TO FINANCIAL STATEMENTS
22
<PAGE>

<TABLE>
<S> <C>
MORGAN STANLEY DEAN WITTER CONVERTIBLE
SECURITIES TRUST
REPORT OF INDEPENDENT ACCOUNTANTS
</TABLE>

TO THE SHAREHOLDERS AND TRUSTEES
OF MORGAN STANLEY DEAN WITTER CONVERTIBLE SECURITIES TRUST

In our opinion, the accompanying statement of assets and liabilities, including
the portfolio of investments, and the related statements of operations and of
changes in net assets and the financial highlights present fairly, in all
material respects, the financial position of Morgan Stanley Dean Witter
Convertible Securities Trust (the "Fund") at September 30, 1999, the results of
its operations for the year then ended, the changes in its net assets for each
of the two years in the period then ended and the financial highlights for each
of the periods presented, in conformity with generally accepted accounting
principles. These financial statements and financial highlights (hereafter
referred to as "financial statements") are the responsibility of the Fund's
management; our responsibility is to express an opinion on these financial
statements based on our audits. We conducted our audits of these financial
statements in accordance with generally accepted auditing standards which
require that we plan and perform the audit to obtain reasonable assurance about
whether the financial statements are free of material misstatement. An audit
includes examining, on a test basis, evidence supporting the amounts and
disclosures in the financial statements, assessing the accounting principles
used and significant estimates made by management, and evaluating the overall
financial statement presentation. We believe that our audits, which included
confirmation of securities at September 30, 1999 by correspondence with the
custodian and brokers, provide a reasonable basis for the opinion expressed
above.

PricewaterhouseCoopers LLP
1177 AVENUE OF THE AMERICAS
NEW YORK, NEW YORK 10036
NOVEMBER 10, 1999

1999 FEDERAL TAX NOTICE (UNAUDITED)

During the fiscal year ended September 30, 1999, 45.27% of the
income dividends paid qualified for the dividends received
deduction available to corporations.

23
<PAGE>

TRUSTEES

Michael Bozic
Charles A. Fiumefreddo
Edwin J. Garn
Wayne E. Hedien
Dr. Manuel H. Johnson
Michael E. Nugent
Philip J. Purcell
John L. Schroeder

OFFICERS

Charles A. Fiumefreddo
Chairman and Chief Executive Officer

Mitchell M. Merin
President

Barry Fink
Vice President, Secretary and General Counsel

Peter M. Avelar
Vice President

Ellen Gold
Assistant Vice President

Thomas F. Caloia
Treasurer

TRANSFER AGENT

Morgan Stanley Dean Witter Trust FSB
Harborside Financial Center - Plaza Two
Jersey City, New Jersey 07311

INDEPENDENT ACCOUNTANTS

PricewaterhouseCoopers LLP
1177 Avenue of the Americas
New York, New York 10036

INVESTMENT MANAGER

Morgan Stanley Dean Witter Advisors Inc.
Two World Trade Center
New York, New York 10048

This report is submitted for the general information of shareholders of the
Fund. For more detailed information about the Fund, its officers and trustees,
fees, expenses and other pertinent information, please see the prospectus of
the Fund.

This report is not authorized for distribution to prospective investors in the
Fund unless preceded or accompanied by an effective prospectus. Read the
prospectus carefully before investing.