0001104659-12-079157.txt : 20121120 0001104659-12-079157.hdr.sgml : 20121120 20121120105706 ACCESSION NUMBER: 0001104659-12-079157 CONFORMED SUBMISSION TYPE: 485BPOS PUBLIC DOCUMENT COUNT: 7 FILED AS OF DATE: 20121120 DATE AS OF CHANGE: 20121120 EFFECTIVENESS DATE: 20121120 FILER: COMPANY DATA: COMPANY CONFORMED NAME: ACTIVE ASSETS CALIFORNIA TAX FREE TRUST CENTRAL INDEX KEY: 0000877243 IRS NUMBER: 133622792 STATE OF INCORPORATION: MA FISCAL YEAR END: 0630 FILING VALUES: FORM TYPE: 485BPOS SEC ACT: 1933 Act SEC FILE NUMBER: 033-41685 FILM NUMBER: 121216809 BUSINESS ADDRESS: STREET 1: 522 FIFTH AVENUE CITY: NEW YORK STATE: NY ZIP: 10036 BUSINESS PHONE: 800-869-6397 MAIL ADDRESS: STREET 1: 522 FIFTH AVENUE CITY: NEW YORK STATE: NY ZIP: 10036 FILER: COMPANY DATA: COMPANY CONFORMED NAME: ACTIVE ASSETS CALIFORNIA TAX FREE TRUST CENTRAL INDEX KEY: 0000877243 IRS NUMBER: 133622792 STATE OF INCORPORATION: MA FISCAL YEAR END: 0630 FILING VALUES: FORM TYPE: 485BPOS SEC ACT: 1940 Act SEC FILE NUMBER: 811-06350 FILM NUMBER: 121216810 BUSINESS ADDRESS: STREET 1: 522 FIFTH AVENUE CITY: NEW YORK STATE: NY ZIP: 10036 BUSINESS PHONE: 800-869-6397 MAIL ADDRESS: STREET 1: 522 FIFTH AVENUE CITY: NEW YORK STATE: NY ZIP: 10036 0000877243 S000004036 ACTIVE ASSETS CALIFORNIA TAX FREE TRUST C000011321 ACTIVE ASSETS CALIFORNIA TAX FREE TRUST aacxx 485BPOS 1 a12-20465_15485bpos.htm 485BPOS

As filed with the Securities and Exchange Commission on November 20, 2012

Registration Nos.: 33-41685
811-6350

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT
  UNDER THE SECURITIES ACT OF 1933  
x

  Pre-Effective Amendment No.  o

  Post-Effective Amendment No. 29  x

and/or

  REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY  

  ACT OF 1940  x

  Amendment No. 30  x

Active Assets California Tax-Free Trust

(A Massachusetts business trust)

(Exact Name of Registrant as Specified in Charter)

522 Fifth Avenue
New York, New York 10036

(Address of Principal Executive Office)

Registrant's Telephone Number, Including Area Code: (212) 296-6970

Stefanie V. Chang Yu, Esq.
522 Fifth Avenue
New York, New York 10036

(Name and Address of Agent for Service)

Copy to:

Carl Frischling, Esq.
Kramer Levin Naftalis & Frankel LLP
1177 Avenue of the Americas
New York, New York 10036
  Stuart M. Strauss, Esq.
Dechert LLP
1095 Avenue of the Americas
New York, New York 10036
 

Approximate Date of Proposed Public Offering:

As soon as practicable after this Post-Effective Amendment becomes effective.

It is proposed that this filing will become effective (check appropriate box):

   

X

 

Immediately upon filing pursuant to paragraph (b)

 
     

On October 31, 2012 pursuant to paragraph (b)

 
     

60 days after filing pursuant to paragraph (a)(1)

 
     

On (date) pursuant to paragraph (a)(1)

 
     

75 days after filing pursuant to paragraph (a)(2)

 
     

On (date) pursuant to paragraph (a)(2) of Rule 485.

 

  Amending the Prospectus and Updating Financial Statements

  If appropriate, check the following box:

       

This post-effective amendment designates a new effective

 
       

date for a previously filed post-effective amendment.

 



 

SIGNATURES

 

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of the Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York and State of New York on the 20th day of November, 2012.

 

ACTIVE ASSETS CALIFORNIA TAX-FREE TRUST

 

 

 

By:

 

/s/ KEVIN KLINGERT

 

 

 

Kevin Klingert

 

 

President and Principal Executive Officer

 

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment No. 29 has been signed below by the following persons in the capacities and on the dates indicated.

 

Signatures

 

Title

 

Date

 

 

 

 

 

 

(1)

Principal Executive Officer

 

President and Principal

 

 

 

 

 

Executive Officer

 

 

 

 

 

 

 

 

By:

 

/s/ KEVIN KLINGERT

 

 

 

 

 

 

Kevin Klingert

 

 

 

 

 

 

 

 

 

November 20, 2012

 

 

 

 

 

 

(2)

Principal Financial Officer

 

Chief Financial Officer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

By:

/s/ FRANCIS J. SMITH

 

 

 

 

 

 

Francis J. Smith

 

 

 

 

 

 

 

 

 

November 20, 2012

 

 

 

 

 

 

(3)

Majority of the Trustees

 

 

 

 

 

 

 

 

 

 

 

James F. Higgins

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

By:

/s/ STEFANIE V. CHANG YU

 

 

 

 

 

 

Stefanie V. Chang Yu

 

 

 

 

 

 

Attorney-in-Fact

 

 

 

 

 

 

 

 

 

November 20, 2012

 

 

 

 

 

 

 

 

 

 

 

 

Frank L. Bowman

Michael F. Klein

 

 

 

 

Michael Bozic

Michael E. Nugent (Chairman)

 

 

 

 

Kathleen A. Dennis

W. Allen Reed

 

 

 

 

Manuel H. Johnson

Fergus Reid

 

 

 

 

Joseph J. Kearns

 

 

 

 

 

 

 

 

 

By:

/s/ CARL FRISCHLING

 

 

 

 

 

 

Carl Frischling

 

 

 

 

 

 

Attorney-in-Fact

 

 

 

 

 

 

 

 

 

November 20, 2012

 



 

EXHIBIT INDEX

 

Index No.

 

Description of Exhibit

 

 

 

EX-101.INS

 

XBRL Instance Document

EX-101.SCH

 

XBRL Taxonomy Extension Schema Document

EX-101.CAL

 

XBRL Taxonomy Extension Calculation Linkbase

EX-101.DEF

 

XBRL Taxonomy Extension Definition Linkbase

EX-101.LAB

 

XBRL Taxonomy Extension Labels Linkbase

EX-101.PRE

 

XBRL Taxonomy Extension Presentation Linkbase

 

EX-101.INS 2 ck0000877243-20120630.xml XBRL INSTANCE DOCUMENT 485BPOS 2012-06-30 0000877243 2012-10-31 ACTIVE ASSETS CALIFORNIA TAX FREE TRUST false 2012-10-26 2012-10-31 <div style="display:none">~ http://www.morganstanley.com/role/ExpenseExample_S000004051Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/BarChartData_S000004051Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> (800) 869-NEWS <tt>Active Assets Tax-Free Trust is a money market fund that seeks to provide as<br />high a level of daily income exempt from federal personal income tax as is<br />consistent with stability of principal and liquidity.</tt> <tt>The example below is intended to help you compare the cost of investing in the<br />Fund with the cost of investing in other mutual funds.<br /> <br />The example assumes that you invest $10,000 in the Fund, your investment has a<br />5% return each year, and the Fund's operating expenses remain the same. Although<br />your actual costs may be higher or lower, based on these assumptions your costs<br />would be:</tt> <tt>The Fund will invest in high quality, short-term securities that are normally<br />municipal obligations that pay interest exempt from federal income taxes. The<br />Adviser seeks to maintain the Fund's share price at $1.00. The Fund has a<br />fundamental policy of investing at least 80% of its net assets in securities <br />the interest on which is exempt from federal personal income tax. This policy <br />may not be changed without shareholder approval. In addition, the Fund may <br />invest up to 20% of its net assets in securities that pay interest income <br />subject to the "alternative minimum tax," and some taxpayers may have to pay <br />tax on a Fund distribution of this income. For more information, please see <br />the "Tax Consequences" section beginning on page 26 of this Prospectus.<br /> <br />Municipal obligations are securities issued by state and local governments and<br />their agencies. These securities typically are "general obligation" or "revenue"<br />bonds, notes or commercial paper, including participations in lease obligations<br />and installment purchase contracts of municipalities.<br /> <br />The Fund may purchase debt obligations that have fixed, variable or floating<br />rates of interest. The interest rates payable on variable or floating rate<br />obligations may fluctuate based upon changes in market rates.<br /> <br />The Fund's investments may include tender option bonds and custodial receipts.<br />Tender option bonds are municipal obligations held pursuant to a custodial<br />arrangement and issued pursuant to an agreement with a third-party such as a<br />bank or financial institution to provide the holder with the option of tendering <br />the bond at periodic intervals. The holder of the tender option bond effectively <br />holds a demand obligation that bears interest at prevailing short-term rates. <br />Custodial receipts represent interests in future interest and/or principal <br />payments on U.S. government securities or municipal obligations. Additionally, <br />the Fund may invest in investment companies, including money market funds some <br />or all of which may be advised or managed by the Adviser or its affiliates.</tt> Active Assets Tax-Free Trust Example Investment Objective The Fund's past performance does not indicate how the Fund will perform in the future. Principal Risks These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. Annual Total Returns--Calendar Years Past Performance <tt>For the Fund's most recent 7-day annualized yield you may call toll-free (800)<br />869-NEWS.</tt> The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing the Fund's average annual returns for the one, five and 10 year periods. <tt>The year-to-date total return as of September 30, 2012 was 0.01%.<br /> <br />High Quarter 6/30/07 0.83%<br /> <br />Low Quarter 3/31/11 0.00%</tt> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Average Annual Total Returns (as of December 31, 2011) Although the Fund seeks to preserve the value of your investment at $1.00 per share, if it is unable to do so, it is possible to lose money by investing in the Fund. <tt>There is no assurance that the Fund will achieve its investment objectives.<br />Although the Fund seeks to preserve the value of your investment at $1.00 per<br />share, if it is unable to do so, it is possible to lose money by investing in<br />the Fund. The principal risks of investing in the Fund include:<br /> <br />&#x2022; Credit and Interest Rate Risk. Debt obligations, such as bonds, are subject <br />&#xA0;&#xA0;to two types of risk: credit risk and interest rate risk. Credit risk refers <br />&#xA0;&#xA0;to thepossibility that the issuer of a security will be unable to make interest<br />&#xA0;&#xA0;payments and/or repay the principal on its debt. In the case of revenue bonds,<br />&#xA0;&#xA0;notes or commercial paper, for example, the credit risk is the possibility that<br />&#xA0;&#xA0;the user fees from a project or other specified revenue sources are insufficient<br />&#xA0;&#xA0;to meet interest and/or principal payment obligations. Interest rate risk refers<br />&#xA0;&#xA0;to fluctuations in the value of a debt security resulting from changes in the<br />&#xA0;&#xA0;general level of interest rates.<br /> <br />&#x2022; Tender Option Bonds and Custodial Receipts. The risks of tender option bonds<br />&#xA0;&#xA0;and custodial receipts include the risk that the owner of such instruments may<br />&#xA0;&#xA0;not be considered the owner for federal income tax purposes and thus will not be<br />&#xA0;&#xA0;entitled to treat such interest as exempt from federal income tax. Additionally,<br />&#xA0;&#xA0;the occurrence of certain defaults or a credit rating downgrade on the underlying <br />&#xA0;&#xA0;security may impair the ability to tender the bond or receipt back to the third-party <br />&#xA0;&#xA0;provider of the demand option, thus causing the bond or receipt to become illiquid.<br /> <br />&#x2022; Investment Companies. An investment in an investment company is subject to the<br />&#xA0;&#xA0;underlying risks of that investment company's portfolio securities. In addition<br />&#xA0;&#xA0;to the Fund's fees and expenses, the Fund generally would bear its share of the<br />&#xA0;&#xA0;investment company's fees and expenses.<br /> <br />Shares of the Fund are not bank deposits and are not guaranteed or insured by<br />the FDIC or any other government agency.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and table below provide some indication of the risks of investing<br />in the Fund by showing changes in the Fund's performance from year to year and<br />by showing the Fund's average annual returns for the one, five and 10 year<br />periods. The Fund's past performance does not indicate how the Fund will perform<br />in the future.</tt> <tt>The table below describes the fees and expenses that you may pay if you buy and<br />hold shares of the Fund. The Fund is a no-load fund. The Fund does not impose<br />any sales charges.</tt> <div style="display:none">~ http://www.morganstanley.com/role/OperatingExpensesData_S000004051Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/PerformanceTableData_S000004051Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Shares of the Fund are not bank deposits and are not guaranteed or insured by the FDIC or any other government agency. AATXX 0.0099 Low Quarter High Quarter 2012-09-30 14 2007-06-30 45 0.0000 0.0074 -0.0027 0.0001 179 79 0.0328 0.0083 0.0001 0.0007 0.0173 0.0024 2011-03-31 0.0004 0.0101 0.0194 The year-to-date total return 0.0001 0.0057 0.0010 0.0123 0.0014 0.0041 0.0301 0.0001 <div style="display:none">~ http://www.morganstanley.com/role/ExpenseExample_S000004050Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/BarChartData_S000004050Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>Active Assets Money Trust is a money market fund that seeks to provide high<br />current income, preservation of capital and liquidity.</tt> <tt>The example below is intended to help you compare the cost of investing in the<br />Fund with the cost of investing in other mutual funds.<br /> <br />The example assumes that you invest $10,000 in the Fund, your investment has a<br />5% return each year, and the Fund's operating expenses remain the same. Although<br />your actual costs may be higher or lower, based on these assumptions your costs<br />would be:</tt> <tt>The Fund invests in high quality, short-term debt obligations. In selecting<br />investments, the Adviser and/or Morgan Stanley Investment Management Limited<br />("Sub-Adviser") seek to maintain the Fund's share price at $1.00. The Fund's<br />investments include the following money market instruments: corporate<br />obligations (including but not limited to commercial paper); debt obligations <br />of U.S.-regulated banks (including domestic branches or subsidiaries of foreign<br />banks) and instruments secured by those obligations (including certificates of<br />deposit); certificates of deposit of savings banks and savings and loan<br />associations; debt obligations issued or guaranteed as to principal and interest<br />by the U.S. Government, its agencies or instrumentalities, including U.S.<br />government securities guaranteed under the Federal Deposit Insurance Corporation<br />("FDIC") Temporary Liquidity Guarantee Program; asset-backed securities; U.S.<br />dollar-denominated foreign bank obligations; and repurchase agreements.</tt> Active Assets Money Trust Example Investment Objectives The Fund's past performance does not indicate how the Fund will perform in the future. Principal Risks Annual Total Returns--Calendar Years Past Performance <tt>For the Fund's most recent 7-day annualized yield you may call toll-free (800)<br />869-NEWS.</tt> The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing the Fund's average annual returns for the one, five and 10 year periods. <tt>The year-to-date total return as of September 30, 2012 was 0.01%.<br /> <br />High Quarter 9/30/07 1.24%<br /> <br />Low Quarter 6/30/09 0.00%</tt> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Average Annual Total Returns (as of December 31, 2011) Although the Fund seeks to preserve the value of your investment at $1.00 per share, if it is unable to do so, it is possible to lose money by investing in the Fund. <tt>There is no assurance that the Fund will achieve its investment objectives.<br />Although the Fund seeks to preserve the value of your investment at $1.00 per<br />share, if it is unable to do so, it is possible to lose money by investing in<br />the Fund. The principal risks of investing in the Fund include:<br /> <br />&#x2022; Credit and Interest Rate Risk. Debt obligations, such as bonds, are subject <br />&#xA0;&#xA0;to two types of risk: credit and interest rate risk. Credit risk refers to <br />&#xA0;&#xA0;the possibility that the issuer of a security will be unable to make interest<br />&#xA0;&#xA0;payments and/or repay the principal on its debt. Interest rate risk refers to<br />&#xA0;&#xA0;fluctuations in the value of a debt security resulting from changes in the<br />&#xA0;&#xA0;general level of interest rates.<br /> <br />&#x2022; U.S. Government Securities. With respect to U.S. government securities that<br />&#xA0;&#xA0;are not backed by the full faith and credit of the United States, there is the<br />&#xA0;&#xA0;risk that the U.S. Government will not provide financial support to such U.S.<br />&#xA0;&#xA0;government agencies, instrumentalities or sponsored enterprises if it is not<br />&#xA0;&#xA0;obligated to do so by law.<br /> <br />&#x2022; Asset-Backed Securities. Asset-backed securities involve the risk that the<br />&#xA0;&#xA0;various federal and state consumer laws and other legal and economic factors <br />&#xA0;&#xA0;may result in the collateral backing the securities being insufficient to <br />&#xA0;&#xA0;support payment on the securities. Some asset-backed securities also entail <br />&#xA0;&#xA0;prepayment risk, which may vary depending on the type of asset.<br /> <br />&#x2022; Foreign Money Market Securities. Investing in money market securities of<br />&#xA0;&#xA0;foreign issuers involves some additional risks, including the possibility of<br />&#xA0;&#xA0;adverse political, economic or other developments affecting the issuers of <br />&#xA0;&#xA0;these securities.<br /> <br />&#x2022; Repurchase Agreements. Repurchase agreements are subject to risks associated<br />&#xA0;&#xA0;with the possibility of default by the seller at a time when the collateral has<br />&#xA0;&#xA0;declined in value, or insolvency of the seller, which may affect the Fund's<br />&#xA0;&#xA0;right to control the collateral and result in certain costs and delays.<br /> <br />Shares of the Fund are not bank deposits and are not guaranteed or insured by<br />the FDIC or any other government agency.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and table below provide some indication of the risks of investing<br />in the Fund by showing changes in the Fund's performance from year to year and<br />by showing the Fund's average annual returns for the one, five and 10 year<br />periods. The Fund's past performance does not indicate how the Fund will perform<br />in the future.</tt> <tt>The table below describes the fees and expenses that you may pay if you buy and<br />hold shares of the Fund. The Fund is a no-load fund. The Fund does not impose<br />any sales charges.</tt> <div style="display:none">~ http://www.morganstanley.com/role/OperatingExpensesData_S000004050Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/PerformanceTableData_S000004050Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Shares of the Fund are not bank deposits and are not guaranteed or insured by the FDIC or any other government agency. (800) 869-NEWS AAMXX 0.0146 Low Quarter High Quarter 2012-09-30 24 2007-09-30 74 0.0000 0.0099 -0.0019 0.0001 293 130 0.0501 0.0124 0.0001 0.0008 0.0263 0.0024 These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. 2009-06-30 0.0003 0.0152 0.0285 The year-to-date total return 0.0001 0.0078 0.0010 0.0183 0.0023 0.0042 0.0468 0.0001 <div style="display:none">~ http://www.morganstanley.com/role/ExpenseExample_S000004040Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/BarChartData_S000004040Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>Active Assets Government Securities Trust is a money market fund that seeks to<br />provide high current income, preservation of capital and liquidity.</tt> <tt>The example below is intended to help you compare the cost of investing in the<br />Fund with the cost of investing in other mutual funds.<br /> <br />The example assumes that you invest $10,000 in the Fund, your investment has a<br />5% return each year, and the Fund's operating expenses remain the same. Although<br />your actual costs may be higher or lower, based on these assumptions your costs<br />would be:</tt> <tt>The Fund invests in high quality, short-term U.S. government securities. In<br />selecting investments, the Adviser and/or Morgan Stanley Investment Management<br />Limited ("Sub-Adviser") seek to maintain the Fund's share price at $1.00. The<br />U.S. government securities that the Fund may purchase include: U.S Treasury<br />bills, notes and bonds, all of which are direct obligations of the U.S.<br />Government; securities issued by agencies and instrumentalities of the U.S.<br />Government, which are backed by the full faith and credit of the United States;<br />securities issued by agencies and instrumentalities which are not backed by the<br />full faith and credit of the United States, but whose issuing agency or<br />instrumentality has the right to borrow from the U.S. Treasury to meet its<br />obligations; securities issued by agencies and instrumentalities which are<br />backed solely by the credit of the issuing agency or instrumentality; and<br />securities guaranteed under the FDIC Temporary Liquidity Guarantee Program. <br />The Fund also may invest up to 10% of its assets in FDIC insured certificates <br />of deposit of banks and savings and loan institutions. In addition, the Fund <br />may invest in repurchase agreements.</tt> Active Assets Government Securities Trust Example Investment Objectives The Fund's past performance does not indicate how the Fund will perform in the future. Principal Risks These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. Annual Total Returns--Calendar Years Past Performance <tt>For the Fund's most recent 7-day annualized yield you may call toll-free (800)<br />869-NEWS.</tt> The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing the Fund's average annual returns for the one, five and 10 year periods. <tt>The year-to-date total return as of September 30, 2012 was 0.01%.<br /> <br />High Quarter 9/30/06 1.16%<br /> <br />Low Quarter 6/30/09 0.00%</tt> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Average Annual Total Returns (as of December 31, 2011) Although the Fund seeks to preserve the value of your investment at $1.00 per share, if it is unable to do so, it is possible to lose money by investing in the Fund. <tt>There is no assurance that the Fund will achieve its investment objectives.<br />Although the Fund seeks to preserve the value of your investment at $1.00 per<br />share, if it is unable to do so, it is possible to lose money by investing in<br />the Fund. The principal risks of investing in the Fund include:<br /> <br />&#x2022; Credit and Interest Rate Risk. Debt obligations, such as bonds, are subject to<br />&#xA0;&#xA0;two types of risk: credit risk and interest rate risk. Credit risk refers to the<br />&#xA0;&#xA0;possibility that the issuer of a security will be unable to make interest payments <br />&#xA0;&#xA0;and/or repay the principal on its debt. Interest rate risk refers to fluctuations <br />&#xA0;&#xA0;in the value of a debt security resulting from changes in the general level of <br />&#xA0;&#xA0;interest rates.<br /> <br />&#x2022; U.S. Government Securities. With respect to U.S. government securities that<br />&#xA0;&#xA0;are not backed by the full faith and credit of the United States, there is the<br />&#xA0;&#xA0;risk that the U.S. Government will not provide financial support to such U.S.<br />&#xA0;&#xA0;government agencies, instrumentalities or sponsored enterprises if it is not<br />&#xA0;&#xA0;obligated to do so by law.<br /> <br />&#x2022; Repurchase Agreements. Repurchase agreements are subject to risks associated<br />&#xA0;&#xA0;with the possibility of default by the seller at a time when the collateral <br />&#xA0;&#xA0;has declined in value, or insolvency of the seller, which may affect the Fund's<br />&#xA0;&#xA0;right to control the collateral and result in certain costs and delays.<br /> <br />Shares of the Fund are not bank deposits and are not guaranteed or insured by<br />the FDIC or any other government agency.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and table below provide some indication of the risks of investing<br />in the Fund by showing changes in the Fund's performance from year to year and<br />by showing the Fund's average annual returns for the one, five and 10 year<br />periods. The Fund's past performance does not indicate how the Fund will perform<br />in the future.</tt> <tt>The table below describes the fees and expenses that you may pay if you buy and<br />hold shares of the Fund. The Fund is a no-load fund. The Fund does not impose<br />any sales charges.</tt> <div style="display:none">~ http://www.morganstanley.com/role/OperatingExpensesData_S000004040Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/PerformanceTableData_S000004040Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Shares of the Fund are not bank deposits and are not guaranteed or insured by the FDIC or any other government agency. (800) 869-NEWS AAGXX 0.0125 Low Quarter High Quarter 2012-09-30 11 2006-09-30 35 0.0000 0.0079 -0.0059 0.0001 141 62 0.0464 0.0116 0.0001 0.0015 0.0199 0.0045 2009-06-30 0.0001 0.0132 0.0263 The year-to-date total return 0.0001 0.0060 0.0010 0.0162 0.0011 0.0070 0.0439 0.0001 <div style="display:none">~ http://www.morganstanley.com/role/ExpenseExample_S000004036Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/BarChartData_S000004036Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <tt>Active Assets California Tax-Free Trust is a money market fund that seeks to<br />provide as high a level of daily income exempt from federal and California<br />personal income tax as is consistent with stability of principal and liquidity.</tt> <tt>The example below is intended to help you compare the cost of investing in the<br />Fund with the cost of investing in other mutual funds.<br /> <br />The example assumes that you invest $10,000 in the Fund, your investment has a<br />5% return each year, and the Fund's operating expenses remain the same. Although<br />your actual costs may be higher or lower, based on these assumptions your costs<br />would be:</tt> <tt>The Fund will invest in high quality, short-term securities that are normally<br />municipal obligations that pay interest exempt from federal and California<br />personal income taxes. The Adviser seeks to maintain the Fund's share price <br />at$1.00. The Adviser generally invests substantially all of the Fund's assets <br />in California municipal obligations and the Fund has a fundamental policy of<br />investing at least 80% of its net assets in securities the interest on which <br />is exempt from federal and California personal income tax. This policy may not <br />be changed without shareholder approval. In addition, the Fund may invest up <br />to 20% of its net assets in securities that pay interest income subject to the<br />"alternative minimum tax," and some taxpayers may have to pay tax on a Fund<br />distribution of this income. For more information, see the "Tax Consequences"<br />section beginning on page 26 of this Prospectus.<br /> <br />Municipal obligations are securities issued by state and local governments and<br />their agencies. These securities typically are "general obligation" or "revenue"<br />bonds, notes or commercial paper, including participations in lease obligations<br />and installment purchase contracts of municipalities.<br /> <br />The Fund may purchase debt obligations that have fixed, variable or floating<br />rates of interest. The interest rates payable on variable or floating rate<br />obligations may fluctuate based upon changes in market rates.<br /> <br />The Fund's investments may include tender option bonds and custodial receipts.<br />Tender option bonds are municipal obligations held pursuant to a custodial<br />arrangement and issued pursuant to an agreement with a third-party such as <br />a bank or financial institution to provide the holder with the option of <br />tendering the bond at periodic intervals. The holder of the tender option <br />bond effectively holds a demand obligation that bears interest at prevailing <br />short-term rates. Custodial receipts represent interests in future interest <br />and/or principal payments on U.S. government securities or municipal obligations. <br />Additionally, the Fund may invest in investment companies, including money market <br />funds some or all of which may be advised or managed by the Adviser or its <br />affiliates.</tt> Active Assets California Tax-Free Trust Example Investment Objective The Fund's past performance does not indicate how the Fund will perform in the future. Principal Risks These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. Annual Total Returns--Calendar Years Past Performance <tt>For the Fund's most recent 7-day annualized yield you may call toll-free (800)<br />869-NEWS.</tt> The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing the Fund's average annual returns for the one, five and 10 year periods. <tt>The year-to-date total return as of September 30, 2012 was 0.01%.<br /> <br />High Quarter 6/30/07 0.79%<br /> <br />Low Quarter 6/30/09 0.00%</tt> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) Average Annual Total Returns (as of December 31, 2011) Although the Fund seeks to preserve the value of your investment at $1.00 per share, if it is unable to do so, it is possible to lose money by investing in the Fund. <tt>There is no assurance that the Fund will achieve its investment objectives.<br />Although the Fund seeks to preserve the value of your investment at $1.00 per<br />share, if it is unable to do so, it is possible to lose money by investing in<br />the Fund. The principal risks of investing in the Fund include:<br /> <br />&#x2022; Credit and Interest Rate Risk. Debt obligations, such as bonds, are subject <br />&#xA0;&#xA0;to two types of risk: credit risk and interest rate risk. Credit risk refers <br />&#xA0;&#xA0;to the possibility that the issuer of a security will be unable to make interest<br />&#xA0;&#xA0;payments and/or repay the principal on its debt. In the case of revenue bonds,<br />&#xA0;&#xA0;notes or commercial paper, for example, the credit risk is the possibility that<br />&#xA0;&#xA0;the user fees from a project or other specified revenue sources are insufficient<br />&#xA0;&#xA0;to meet interest and/or principal payment obligations. Interest rate risk refers<br />&#xA0;&#xA0;to fluctuations in the value of a debt security resulting from changes in the<br />&#xA0;&#xA0;general level of interest rates.<br /> <br />&#x2022; Tender Option Bonds and Custodial Receipts. The risks of tender option bonds<br />&#xA0;&#xA0;and custodial receipts include the risk that the owner of such instruments may<br />&#xA0;&#xA0;not be considered the owner for federal income tax purposes and thus will not be<br />&#xA0;&#xA0;entitled to treat such interest as exempt from federal income tax. Additionally,<br />&#xA0;&#xA0;the occurrence of certain defaults or a credit rating downgrade on the underlying <br />&#xA0;&#xA0;security may impair the ability to tender the bond or receipt back to the <br />&#xA0;&#xA0;third-party provider of the demand option, thus causing the bond or receipt<br />&#xA0;&#xA0;to become illiquid.<br /> <br />&#x2022; Investment Companies. An investment in an investment company is subject to the<br />&#xA0;&#xA0;underlying risks of that investment company's portfolio securities. In addition<br />&#xA0;&#xA0;to the Fund's fees and expenses, the Fund generally would bear its share of the<br />&#xA0;&#xA0;investment company's fees and expenses.<br /> <br />&#x2022; California Municipal Securities Risks. As the Fund invests principally in<br />&#xA0;&#xA0;municipal obligations issued by state and local governments and their agencies,<br />&#xA0;&#xA0;the Fund is susceptible to political, economic, or other factors affecting<br />&#xA0;&#xA0;issuers of California municipal obligations. The deterioration of California's<br />&#xA0;&#xA0;fiscal situation as a result of recent economic conditions increases the risk <br />&#xA0;&#xA0;of investing in California municipal securities. Several major ratings agencies<br />&#xA0;&#xA0;have downgraded California's general obligation bond rating in recent years. A<br />&#xA0;&#xA0;default or credit rating downgrade of a small number of California municipal<br />&#xA0;&#xA0;security issuers could affect the market values and marketability of all<br />&#xA0;&#xA0;California municipal obligations held by the Fund and the Fund's performance.<br /> <br />Shares of the Fund are not bank deposits and are not guaranteed or insured by<br />the FDIC or any other government agency.</tt> Fees and Expenses Principal Investment Strategies <tt>The bar chart and table below provide some indication of the risks of investing<br />in the Fund by showing changes in the Fund's performance from year to year and<br />by showing the Fund's average annual returns for the one, five and 10 year<br />periods. The Fund's past performance does not indicate how the Fund will perform<br />in the future.</tt> <tt>The table below describes the fees and expenses that you may pay if you buy and<br />hold shares of the Fund. The Fund is a no-load fund. The Fund does not impose<br />any sales charges.</tt> <div style="display:none">~ http://www.morganstanley.com/role/OperatingExpensesData_S000004036Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> <div style="display:none">~ http://www.morganstanley.com/role/PerformanceTableData_S000004036Member column dei_LegalEntityAxis compact * column rr_ProspectusShareClassAxis compact * row primary compact * ~</div> Shares of the Fund are not bank deposits and are not guaranteed or insured by the FDIC or any other government agency. (800) 869-NEWS AACXX 0.0080 Low Quarter High Quarter 2012-09-30 14 2007-06-30 45 0.0000 0.0060 -0.0036 0.0001 179 79 0.0310 0.0079 0.0001 0.0007 0.0155 0.0033 2009-06-30 0.0002 0.0093 0.0178 The year-to-date total return 0.0001 0.0041 0.0010 0.0110 0.0014 0.0050 0.0282 0.0001 0000877243 ck0000877243:SummaryS000004036Memberck0000877243:S000004036Memberck0000877243:C000011321Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004036Memberck0000877243:S000004036Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004040Memberck0000877243:S000004040Memberck0000877243:C000011325Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004040Memberck0000877243:S000004040Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004050Memberck0000877243:S000004050Memberck0000877243:C000011336Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004050Memberck0000877243:S000004050Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004051Memberck0000877243:S000004051Memberck0000877243:C000011337Member 2012-10-31 2012-10-31 0000877243 ck0000877243:SummaryS000004051Memberck0000877243:S000004051Member 2012-10-31 2012-10-31 0000877243 2012-10-31 2012-10-31 pure iso4217:USD The Fund's "Distributor," Morgan Stanley Distribution, Inc., its "Adviser," Morgan Stanley Investment Management Inc., and its "Administrator," Morgan Stanley Services Company Inc., have agreed to waive and/or reimburse all or a portion of the Fund's distribution fee, advisory fee and administration fee, respectively, to the extent that total expenses exceed total income on a daily basis. These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. The Fund's "Distributor," Morgan Stanley Distribution, Inc., its "Adviser," Morgan Stanley Investment Management Inc., and its "Administrator," Morgan Stanley Services Company Inc., have agreed to waive and/or reimburse all or a portion of the Fund's distribution fee, advisory fee and administration fee, respectively, to the extent that total expenses exceed total income on a daily basis. These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. The Fund's "Distributor," Morgan Stanley Distribution, Inc., its "Adviser," Morgan Stanley Investment Management Inc., and its "Administrator," Morgan Stanley Services Company Inc., have agreed to waive and/or reimburse all or a portion of the Fund's distribution fee, advisory fee and administration fee, respectively, to the extent that total expenses exceed total income on a daily basis. These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate. 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Label Element Value
Risk Return [Abstract] rr_RiskReturnAbstract  
ProspectusDate rr_ProspectusDate Oct. 31, 2012
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST (Prospectus Summary) | ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
 
Risk Return [Abstract] rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading Active Assets Government Securities Trust
Objective [Heading] rr_ObjectiveHeading Investment Objectives
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock Active Assets Government Securities Trust is a money market fund that seeks to
provide high current income, preservation of capital and liquidity.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The table below describes the fees and expenses that you may pay if you buy and
hold shares of the Fund. The Fund is a no-load fund. The Fund does not impose
any sales charges.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate.
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the cost of investing in the
Fund with the cost of investing in other mutual funds.

The example assumes that you invest $10,000 in the Fund, your investment has a
5% return each year, and the Fund's operating expenses remain the same. Although
your actual costs may be higher or lower, based on these assumptions your costs
would be:
Strategy [Heading] rr_StrategyHeading Principal Investment Strategies
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock The Fund invests in high quality, short-term U.S. government securities. In
selecting investments, the Adviser and/or Morgan Stanley Investment Management
Limited ("Sub-Adviser") seek to maintain the Fund's share price at $1.00. The
U.S. government securities that the Fund may purchase include: U.S Treasury
bills, notes and bonds, all of which are direct obligations of the U.S.
Government; securities issued by agencies and instrumentalities of the U.S.
Government, which are backed by the full faith and credit of the United States;
securities issued by agencies and instrumentalities which are not backed by the
full faith and credit of the United States, but whose issuing agency or
instrumentality has the right to borrow from the U.S. Treasury to meet its
obligations; securities issued by agencies and instrumentalities which are
backed solely by the credit of the issuing agency or instrumentality; and
securities guaranteed under the FDIC Temporary Liquidity Guarantee Program.
The Fund also may invest up to 10% of its assets in FDIC insured certificates
of deposit of banks and savings and loan institutions. In addition, the Fund
may invest in repurchase agreements.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock There is no assurance that the Fund will achieve its investment objectives.
Although the Fund seeks to preserve the value of your investment at $1.00 per
share, if it is unable to do so, it is possible to lose money by investing in
the Fund. The principal risks of investing in the Fund include:

• Credit and Interest Rate Risk. Debt obligations, such as bonds, are subject to
  two types of risk: credit risk and interest rate risk. Credit risk refers to the
  possibility that the issuer of a security will be unable to make interest payments
  and/or repay the principal on its debt. Interest rate risk refers to fluctuations
  in the value of a debt security resulting from changes in the general level of
  interest rates.

• U.S. Government Securities. With respect to U.S. government securities that
  are not backed by the full faith and credit of the United States, there is the
  risk that the U.S. Government will not provide financial support to such U.S.
  government agencies, instrumentalities or sponsored enterprises if it is not
  obligated to do so by law.

• Repurchase Agreements. Repurchase agreements are subject to risks associated
  with the possibility of default by the seller at a time when the collateral
  has declined in value, or insolvency of the seller, which may affect the Fund's
  right to control the collateral and result in certain costs and delays.

Shares of the Fund are not bank deposits and are not guaranteed or insured by
the FDIC or any other government agency.
Risk Money Market Fund [Text] rr_RiskMoneyMarketFund Although the Fund seeks to preserve the value of your investment at $1.00 per share, if it is unable to do so, it is possible to lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution Shares of the Fund are not bank deposits and are not guaranteed or insured by the FDIC or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Past Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock The bar chart and table below provide some indication of the risks of investing
in the Fund by showing changes in the Fund's performance from year to year and
by showing the Fund's average annual returns for the one, five and 10 year
periods. The Fund's past performance does not indicate how the Fund will perform
in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing the Fund's average annual returns for the one, five and 10 year periods.
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance does not indicate how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Annual Total Returns--Calendar Years
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock The year-to-date total return as of September 30, 2012 was 0.01%.

High Quarter 9/30/06 1.16%

Low Quarter 6/30/09 0.00%
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock For the Fund's most recent 7-day annualized yield you may call toll-free (800)
869-NEWS.
Caption rr_AverageAnnualReturnCaption Average Annual Total Returns (as of December 31, 2011)
Money Market Seven Day Yield Phone rr_MoneyMarketSevenDayYieldPhone (800) 869-NEWS
ACTIVE ASSETS GOVERNMENT SECURITIES TRUST (Prospectus Summary) | ACTIVE ASSETS GOVERNMENT SECURITIES TRUST | ACTIVE ASSETS GOVERNMENT SECURITIES TRUST
 
Risk Return [Abstract] rr_RiskReturnAbstract  
Advisory Fee rr_ManagementFeesOverAssets 0.45%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.10%
Other Expenses rr_OtherExpensesOverAssets 0.15%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.70%
Fee Waivers and/or Expense Reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.59%) [1]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements rr_NetExpensesOverAssets 0.11% [1]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 11
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 35
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 62
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 141
Annual Return 2002 rr_AnnualReturn2002 1.25%
Annual Return 2003 rr_AnnualReturn2003 0.60%
Annual Return 2004 rr_AnnualReturn2004 0.79%
Annual Return 2005 rr_AnnualReturn2005 2.63%
Annual Return 2006 rr_AnnualReturn2006 4.39%
Annual Return 2007 rr_AnnualReturn2007 4.64%
Annual Return 2008 rr_AnnualReturn2008 1.99%
Annual Return 2009 rr_AnnualReturn2009 0.01%
Annual Return 2010 rr_AnnualReturn2010 0.01%
Annual Return 2011 rr_AnnualReturn2011 0.01%
Year to Date Return, Label rr_YearToDateReturnLabel The year-to-date total return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2012
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 0.01%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel High Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Sep. 30, 2006
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 1.16%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Low Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Jun. 30, 2009
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn 0.00%
1 Year rr_AverageAnnualReturnYear01 0.01%
5 Years rr_AverageAnnualReturnYear05 1.32%
10 Years rr_AverageAnnualReturnYear10 1.62%
[1] The Fund's "Distributor," Morgan Stanley Distribution, Inc., its "Adviser," Morgan Stanley Investment Management Inc., and its "Administrator," Morgan Stanley Services Company Inc., have agreed to waive and/or reimburse all or a portion of the Fund's distribution fee, advisory fee and administration fee, respectively, to the extent that total expenses exceed total income on a daily basis. These fee waivers and/or expense reimbursements will continue for at least one year or until such time as the Fund's Board of Trustees acts to discontinue all or a portion of such waivers and/or expense reimbursements when it deems such action appropriate.
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