Morgan Stanley Us Government Securities Trust NPORT-P Morgan Stanley Long Duration Government Opportunities Fund (Sep 2024 report)

Morgan Stanley Long Duration Government Opportunities Fund
Portfolio of Investments ■ September 30, 2024 (unaudited)

Principal Amount (000)			Coupon Rate			Maturity Date	Value
		Agency Adjustable Rate Mortgages (0.1%)
		Federal Home Loan Mortgage Corporation,
		Conventional Pools:
$	121	1 yr. RFUCC Treasury + 1.91%		6.155	%	10/01/36	$	124,974
	80	1 yr. RFUCC Treasury + 1.74%		6.171		11/01/36		82,300
		Total Agency Adjustable Rate Mortgages (Cost $ 213,823)						207,274
		Agency Bond - Finance (U.S. Government Guaranteed) (0.2%)
	411	Washington Aircraft 1 Co. DAC (Ireland) (Cost $411,428)		2.637		09/15/26		403,191
		Agency Bond - Sovereign (U.S. Government Guaranteed) (0.1%)
	386	Petroleos Mexicanos (Mexico) (Cost $386,250)		2.46		12/15/25		370,759
		Agency Fixed Rate Mortgages (40.9%)
		Federal Home Loan Mortgage Corporation,
		Conventional Pools:
	78			3.00		12/01/49		69,797
		Gold Pools:
	26			3.50		04/01/49		24,223
	101			6.50		03/01/29 - 09/01/32		104,872
	72			7.50		05/01/35		76,471
	40			8.00		08/01/32		41,829
	50			8.50		08/01/31		52,845
		Federal National Mort gage Association,
		Conventional Pools:
	289			2.50		02/01/50		253,379
	324			3.00		05/01/49 - 11/01/49		290,845
	242			3.50		01/01/48 - 07/01/49		227,740
	144			4.50		01/01/25 - 09/01/48		143,019
	32			5.00		01/01/41		32,864
	77			5.50		09/01/35		79,529
	14			6.50		06/01/29 - 02/01/33		14,144
	1			7.00		05/01/31		551
	113			7.50		08/01/37		119,663
	83			8.00		04/01/33		86,468
	94			8.50		10/01/32		99,626
		October TBA:
	11,500	(a)		3.50		10/01/54		10,716,113
	11,600	(a)		4.50		10/01/54		11,407,421

Morgan Stanley Long Duration Government Opportunities Fund
Portfolio of Investments ■ September 30, 2024 (unaudited) continued

Principal Amount (000)			Coupon Rate			Maturity Date	Value
$	22,550	(a)		5.00	%	10/01/54	$	22,535,907
	23,050	(a)		5.50		10/01/54		23,322,819
		Government National Mortgage Association,
		October TBA:
	1,600	(a)		3.00		10/20/54		1,459,655
	10,900	(a)		3.50		10/20/54		10,249,213
	4,500	(a)		5.50		10/20/54		4,544,288
	6,000	(a)		6.00		10/20/54		6,101,660
		Various Pools:
	823			3.50		08/20/45 - 07/20/46		784,629
	347			4.00		07/15/44		340,453
	23			4.50		04/20/49		22,806
	268			5.00		01/20/40 - 12/20/48		273,456
	30			5.125		11/20/37		30,413
	192			5.25		04/20/36 - 09/20/39		196,151
	435			5.375		02/20/36 - 08/20/40		449,426
	2,282			6.00		06/15/28 - 06/20/53		2,345,199
	491			6.50		06/20/53		513,538
	23			7.00		03/20/26 - 07/20/29		24,132
	49			8.00		05/15/26 - 08/15/31		52,076
	2			8.50		07/15/30		2,284
	—@			9.00		02/15/25		84
		Total Agency Fixed Rate Mortgages (Cost $ 97,788,902)						97,089,588
		Collateralized Mortgage Obligations - Agency Collateral Series (83.5%)
		Federal Home Loan Mortgage Corporation,
		IO REMIC
	1,353	5.89% - SOFR30A		0.544	(b)	11/15/43		119,795
		REMIC
	12,297			5.50		02/25/54 - 09/25/54		12,606,179
	21,253			6.00		07/25/53 - 07/25/54		22,516,821
	4,229			6.25		01/25/54		4,517,457
	2,653			6.50		11/25/53		2,840,391
		Federal National Mortgage Association,
		IO REMIC
	461	6.44% - SOFR30A		1.155	(b)	08/25/41		10,248
		REMIC
	2,170			0.00	(c)	11/25/53		1,869,805
	8,655			5.50		05/25/54		8,803,915
	7,205			6.00		10/25/53 - 03/25/54		7,870,877

Morgan Stanley Long Duration Government Opportunities Fund
Portfolio of Investments ■ September 30, 2024 (unaudited) continued

Principal Amount (000)			Coupon Rate			Maturity Date	Value
$	4,597			6.25	%	08/25/53	$	5,071,628
		Government National Mortgage Association,
	3,013			5.00		08/20/54		2,934,160
	7,505			5.50		02/20/54 - 09/20/54		7,679,980
		IO REMIC
	191			5.00		02/16/41		36,969
		REMIC
	2,144	22.55% - SOFR30A		2.626	(b)	07/20/53		2,314,595
	1,983	21.45% - SOFR30A		5.414	(b)	10/20/53		2,186,981
	100,373			6.00		05/20/53 - 01/20/54		106,425,187
	10,104			6.50		11/20/53		10,637,695
		Total Collateralized Mortgage Obligations - Agency Collateral Series (Cost $ 191,105,680)						198,442,683
		Commercial Mortgage-Backed Securities (0.6%)
	6,494	BANK 2019-BNK21, IO		0.956	(d)	10/17/52		215,485
		Citigroup Commercial Mortgage Trust,
		IO
	4,671			0.855	(d)	11/10/48		31,606
	12,337			1.018	(d)	09/10/58		80,379
		Federal Home Loan Mortgage Corp. Multifamily Structured Pass-Through Certificates,
		IO
	24,082			0.436	(d)	04/25/32		544,246
	31,234			0.45	(d)	11/25/27		275,220
	12,784	GS Mortgage Securities Trust, IO		1.345	(d)	10/10/48		127,799
	7,220	JP Morgan Chase Commercial Mortgage Securities Trust, IO		0.705	(d)	12/15/49		65,409
	632	WFRBS Commercial Mortgage Trust, IO		0.00	(d)	08/15/46		1
		Total Commercial Mortgage-Backed Securities (Cost $1,339,289)						1,340,145
		Mortgages - Other (5.6%)
		Cascade Funding Mortgage Trust
	945	(e)		2.976	(d)	07/25/57		466,451
	281	(e)		4.00	(d)	10/25/68		278,957
		FARM Mortgage Trust
	940	(e)		3.037	(d)	03/25/52		716,096
	735	(e)		3.244	(d)	07/25/51		564,821
	1,946	(e)		5.123	(d)	10/01/53		1,637,354

Morgan Stanley Long Duration Government Opportunities Fund
Portfolio of Investments ■ September 30, 2024 (unaudited) continued

Principal Amount (000)			Coupon Rate			Maturity Date	Value
$	2,750	Federal Home Loan Mortgage Corp. Seasoned Credit Risk Transfer Trust		3.00	%	08/25/57 - 05/25/60	$	2,434,965
		Flagstar Mortgage Trust
	4,110	(e)		3.485	(d)	08/25/51		3,423,579
	1,883	(e)		3.505	(d)	10/25/51		1,538,215
		GS Mortgage-Backed Securities Trust
	1,380	(e)		3.187	(d)	01/25/53		853,508
	838	(e)		3.422	(d)	10/25/50		525,513
	1,625	Sequoia Mortgage Trust, Class B4 (e)		2.863	(d)	11/25/51		858,548
		Total Mortgages - Other (Cost $ 11,979,801)						13,298,007
		U.S. Agency Security (3.2%)
	6,935	Tennessee Valley Authority (Cost $7,093,533)		5.25		09/15/39		7,559,927

Number of Shares (000)
		Short-Term Investment (1.9%)
		Investment Company (1.9%)
	4,529	Morgan Stanley Institutional Liquidity Funds — Government Portfolio — Institutional Class, 4.85% (f) (Cost $4,529,078)			$	4,529,078
		Total Investments (Cost $ 314,847,784) (g)(h)	136.1	%		323,240,652
		Liabilities in excess of Other Assets	(36.1	)		(85,674,839	)
		Net Assets	100.0	%	$	237,565,813

@	Principal amount is less than $500.
(a)	Security is subject to delayed delivery.
(b)	Inverse Floating Rate Security - Interest rate fluctuates with an inverse relationship to an associated interest rate. Indicated rate is the effective rate at September 30, 2024.
(c)	Capital appreciation bond.
(d)	Floating or variable rate securities: The rates disclosed are as of September 30, 2024. For securities based on a published reference rate and spread, the reference rate and spread are indicated in the description in the Portfolio of Investments. Certain variable rate securities may not be based on a published reference rate and spread but are determined by the issuer or agent and are based on current market conditions. These securities do not indicate a reference rate and spread in their description in the Portfolio of Investments.
(e)	144A security — Certain conditions for public sale may exist. Unless otherwise noted, these securities are deemed to be liquid.

Morgan Stanley Long Duration Government Opportunities Fund
Portfolio of Investments ■ September 30, 2024 (unaudited) continued

(f)	The Fund invests in the Institutional Class of the Morgan Stanley Institutional Liquidity Funds - Government Portfolio - (the "Liquidity Fund"), an open-end management investment company managed by the Adviser. Advisory fees paid by the Fund are reduced by an amount equal to its pro-rata share of the advisory and administration fees paid by the Fund due to its investment in the Liquidity Fund. For the nine months ended September 30, 2024, advisory fees paid were reduced by $5,218 relating to the Fund's investment in the Liquidity Fund.
(g)	Securities are available for collateral in connection with securities purchased on a forward commitment basis and open futures contracts.
(h)	At September 30, 2024, the aggregate cost for federal income tax purposes approximates the aggregate cost for book purposes. The aggregate gross unrealized appreciation is $9,796,638 and the aggregate gross unrealized depreciation is $1,370,145, resulting in net unrealized appreciation of $8,426,493.
DAC	Designated Activity Company.
IO	Interest Only Security.
REMIC	Real Estate Mortgage Investment Conduit.
RFUCC	Refinitiv USD IBOR Consumer Cash Fallbacks.
SOFR30A	30-Day Average Secured Overnight Financing Rate.
TBA	To Be Announced.

Futures Contracts:

The Fund had the following futures contracts open at September 30, 2024:

	Number of Contracts	Expiration Date	Notional Amount (000)		Value		Unrealized Appreciation (Depreciation)
Long:
U.S. Treasury Long Bond (United States)	171	Dec-24	$	17,100	$	21,236,063	$	(272,532	)
U.S. Treasury 5 yr. Note (United States)	434	Dec-24		43,400		47,689,141		57,641
U.S. Treasury 10 yr. Note (United States)	954	Dec-24		95,400		109,024,312		163,969
U.S. Treasury 10 yr. Ultra Note (United States)	773	Dec-24		77,300		91,443,484		84,547
							$	33,625

Portfolio Composition

CLASSIFICATION	Percentage of Total Investments
Collateralized Mortgage Obligations - Agency Collateral Series		61.4	%
Agency Fixed Rate Mortgages		30.0
Mortgages - Other		4.1
U.S. Agency Security		2.4
Short-Term Investment		1.4
Commercial Mortgage-Backed Securities		0.4
Agency Adjustable Rate Mortgages		0.1
Agency Bond - Sovereign (U.S. Government Guaranteed)		0.1
Agency Bond - Finance (U.S. Government Guaranteed)		0.1
Total		100.0	%*

* Does not include open futures contracts with a value of $269,393,000 and net unrealized appreciation of $33,625.

Morgan Stanley Long Duration Government Opportunities Fund
Notes to the Portfolio of Investments ■ September 30, 2024 (unaudited)

A. Valuation of Investments — (1) Fixed income securities may be valued by an outside pricing service/vendor approved by the Fund’s Board of Trustees (the “Trustees”). The pricing service/vendor may employ a pricing model that takes into account, among other things, bids, yield spreads and/or other market data and specific security characteristics. If Morgan Stanley Investment Management Inc. (the “Adviser”), a wholly-owned subsidiary of Morgan Stanley, determines that the price provided by the outside pricing service/vendor does not reflect the security’s fair value or the pricing service/vendor or exchange is unable to provide a price, prices from reputable brokers/dealers may also be utilized. In these circumstances, the value of the security will be the mean of bid and asked prices obtained from reputable brokers/dealers; (2) portfolio securities for which over-the-counter (“OTC”) market quotations are readily available are valued at its latest reported sales price (or at the market official closing price if such market reports an official closing price), and if there was no trading in the security on a given day and if there is no official closing price from relevant markets for that day, the security is valued at the mean between the last reported bid and asked prices if such bid and asked prices are available on the relevant markets; (3) when market quotations are not readily available, as defined by Rule 2a-5 under the Act, including circumstances under which the Adviser determines that the market quotations are not reflective of a security’s market value, portfolio securities are valued at their fair value as determined in good faith under procedures approved by and under the general supervision of the Trustees. Each business day, the Fund uses a third-party pricing service approved by the Trustees to assist with the valuation of foreign equity securities. Events occurring after the close of trading on foreign exchanges may result in adjustments to the valuation of foreign securities to reflect market trading that occurs after the close of the applicable foreign markets of comparable securities or other instruments that have a strong correlation to the fair-valued securities to more accurately reflect their fair value as of the close of regular trading on the NYSE; (4) futures are valued at the settlement price on the exchange on which they trade or, if a settlement price is unavailable, at the last sale price on the exchange; and (5) investments in mutual funds, including the Morgan Stanley Institutional Liquidity Funds, are valued at the net asset value as of the close of each business day.

In connection with Rule 2a-5 of the Act, the Trustees have designated the Fund’s Adviser as its valuation designee. The valuation designee has responsibility for determining fair value and to make the actual calculations pursuant to the fair valuation methodologies previously approved by the Trustees. Under procedures approved by the Trustees, the Fund’s Adviser, as valuation designee, has formed a Valuation Committee whose members are approved by the Trustees. The Valuation Committee provides administration and oversight of the Fund’s valuation policies and procedures, which are reviewed at least annually by the Trustees. These procedures allow the Fund to utilize independent pricing services, quotations from securities and financial instrument dealers and other market sources to determine fair value.

Morgan Stanley Long Duration Government Opportunities Fund
Notes to the Portfolio of Investments ■ September 30, 2024 (unaudited) continued

Fair Value Measurement: Financial Accounting Standards Board (“FASB”) Accounting Standards Codification^TM ("ASC") 820, "Fair Value Measurement" (“ASC 820”), defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC 820 establishes a three-tier hierarchy to distinguish between (1) inputs that reflect the assumptions market participants would use in valuing an asset or liability developed based on market data obtained from sources independent of the reporting entity (observable inputs); and (2) inputs that reflect the reporting entity's own assumptions about the assumptions market participants would use in valuing an asset or liability developed based on the best information available in the circumstances (unobservable inputs) and to establish classification of fair value measurements for disclosure purposes. Various inputs are used in determining the value of the Fund's investments. The inputs are summarized in the three broad levels listed below:

● Level 1 – unadjusted quoted prices in active markets for identical investments

● Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.)

● Level 3 – significant unobservable inputs including the Fund’s own assumptions in determining the fair value of investments. Factors considered in making this determination may include, but are not limited to, information obtained by contacting the issuer, analysts, or the appropriate stock exchange (for exchange-traded securities), analysis of the issuer's financial statements or other available documents and, if necessary, available information concerning other securities in similar circumstances.

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those securities and the determination of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to each security.

Morgan Stanley Long Duration Government Opportunities Fund
Notes to the Portfolio of Investments ■ September 30, 2024 (unaudited) continued

The following is a summary of the inputs used to value the Fund’s investments as of September 30, 2024:

Investment Type	Level 1 Unadjusted quoted prices			Level 2 Other significant observable inputs		Level 3 Significant unobservable inputs		Total
Assets:
Fixed Income Securities
Agency Adjustable Rate Mortgages	$	—		$	207,274	$	—	$	207,274
Agency Bond - Finance (U.S. Government Guaranteed)		—			403,191		—		403,191
Agency Bond - Sovereign (U.S. Government Guaranteed)		—			370,759		—		370,759
Agency Fixed Rate Mortgages		—			97,089,588		—		97,089,588
Collateralized Mortgage Obligations - Agency Collateral Series		—			198,442,683		—		198,442,683
Commercial Mortgage-Backed Securities		—			1,340,145		—		1,340,145
Mortgages - Other		—			13,298,007		—		13,298,007
U.S. Agency Security		—			7,559,927		—		7,559,927
Total Fixed Income Securities		—			318,711,574		—		318,711,574
Short-Term Investment
Investment Company		4,529,078			—		—		4,529,078
Futures Contracts		306,157			—		—		306,157
Total Assets		4,835,235			318,711,574		—		323,546,809
Liabilities:
Future Contract		(272,532	)		—		—		(272,532	)
Total	$	4,562,703		$	318,711,574	$	—	$	323,274,277

Transfers between investment levels may occur as the markets fluctuate and/or the availability of data used in an investment's valuation changes.