Lord Abbett

Quarterly Portfolio Holdings Report

Lord Abbett
Developing Growth Fund

For the period ended April 30, 2026

Investments	Shares		Fair Value
LONG-TERM INVESTMENTS 99.76%

COMMON STOCKS 99.76%

Aerospace & Defense 10.25%
Aevex Corp. Class A*		467,466	$	14,140,847
Carpenter Technology Corp.		108,256		46,355,219
FTAI Aviation Ltd.		73,746		18,412,164
Karman Holdings, Inc.*		371,888		25,280,946
Kratos Defense & Security Solutions, Inc.*		330,915		20,864,191
Mercury Systems, Inc.*		325,284		25,668,160
Moog, Inc. Class A		33,919		10,220,134
Rocket Lab Corp.*		180,888		14,925,069
VSE Corp.		118,451		20,335,668
Woodward, Inc.		49,819		18,083,799
York Space Systems, Inc.*^(a)		387,959		12,864,720
Total				227,150,917

Beverages 1.53%
Celsius Holdings, Inc.*		301,688		10,127,666
Vita Coco Co., Inc.*		359,992		23,755,872
Total				33,883,538

Biotechnology 15.67%
Abivax SA ADR*		183,074		21,489,226
Arrowhead Pharmaceuticals, Inc.*		223,850		16,448,498
Ascendis Pharma AS (Denmark)*^(a)(b)		84,934		19,482,161
Bridgebio Pharma, Inc.*		554,755		39,448,628
Celcuity, Inc.*		188,321		22,852,753
CG oncology, Inc.*		204,698		13,661,544
Cogent Biosciences, Inc.*		663,487		23,746,200
Dianthus Therapeutics, Inc.*		115,645		10,153,631
Madrigal Pharmaceuticals, Inc.*		82,089		42,472,028
Mirum Pharmaceuticals, Inc.*		263,316		25,623,280
Natera, Inc.*		83,160		17,144,266
Nuvalent, Inc. Class A*		91,136		9,139,118
Oruka Therapeutics, Inc.*		214,960		14,705,414

Investments	Shares		Fair Value
Biotechnology (continued)
Protagonist Therapeutics, Inc.*		138,522	$	13,709,522
PTC Therapeutics, Inc.*		330,938		21,530,826
Revolution Medicines, Inc.*		133,298		19,210,908
Rhythm Pharmaceuticals, Inc.*		201,474		16,391,925
Total				347,209,928

Building Products 2.42%
Madison Air Solutions Corp. Class A*^(a)		345,499		13,191,152
Modine Manufacturing Co.*		158,948		40,472,929
Total				53,664,081

Capital Markets 2.69%
Evercore, Inc. Class A		51,981		16,700,976
Miami International Holdings, Inc.*		472,654		21,973,684
Piper Sandler Cos.		240,796		20,997,411
Total				59,672,071

Construction & Engineering 14.16%
Argan, Inc.		44,171		29,593,687
Cardinal Infrastructure Group, Inc. Class A*^(a)		422,602		22,410,584
Comfort Systems USA, Inc.		43,377		79,824,524
Construction Partners, Inc. Class A*		274,632		33,960,993
IES Holdings, Inc.*		43,441		27,979,479
Legence Corp. Class A*		269,776		23,459,721
MasTec, Inc.*		88,631		34,925,046
Sterling Infrastructure, Inc.*		119,486		61,609,371
Total				313,763,405

Diversified Consumer Services 1.59%
Lincoln Educational Services Corp.*		233,414		9,602,652
Universal Technical Institute, Inc.*		679,600		25,505,388
Total				35,108,040

Investments	Shares		Fair Value
Electrical Equipment 4.77%
Bloom Energy Corp. Class A*		253,478	$	71,825,526
Nextpower, Inc. Class A*		284,957		33,946,927
Total				105,772,453

Electronic Equipment, Instruments & Components 7.44%
Bel Fuse, Inc. Class B		100,105		27,612,963
Cognex Corp.		194,794		10,813,015
Fabrinet (Thailand)*^(b)		72,429		49,503,049
Littelfuse, Inc.		57,077		23,068,811
Sanmina Corp.*		97,628		21,265,331
TTM Technologies, Inc.*		205,985		32,590,947
Total				164,854,116

Entertainment 1.05%
IMAX Corp. (Canada)*^(b)		287,198		10,919,268
Sphere Entertainment Co.*		87,014		12,395,144
Total				23,314,412

Ground Transportation 0.48%
Saia, Inc.*		23,712		10,642,420

Health Care Equipment & Supplies 0.83%
Glaukos Corp.*		128,426		18,450,963

Health Care Providers & Services 2.36%
Guardant Health, Inc.*		599,531		52,207,159

Hotels, Restaurants & Leisure 2.95%
Cava Group, Inc.*		330,862		30,905,820
Life Time Group Holdings, Inc.*		385,225		10,327,882
Navan, Inc. Class A*		1,381,876		24,169,011
Total				65,402,713

Information Technology Services 3.10%
Applied Digital Corp.*^(a)		459,253		15,729,415
DigitalOcean Holdings, Inc.*		357,040		34,429,367
Fastly, Inc. Class A*		736,488		18,600,005
Total				68,758,787

Investments	Shares		Fair Value
Life Sciences Tools & Services 1.08%
Adaptive Biotechnologies Corp.*		1,697,752	$	23,938,303

Machinery 2.32%
CECO Environmental Corp.*		157,848		11,702,851
Crane Co.		50,207		8,923,290
RBC Bearings, Inc.*		51,497		30,851,338
Total				51,477,479

Metals & Mining 0.49%
MP Materials Corp.*^(a)		165,432		10,925,129

Pharmaceuticals 2.26%
Nektar Therapeutics*		273,886		23,291,266
Tarsus Pharmaceuticals, Inc.*		420,038		26,718,617
Total				50,009,883

Professional Services 1.56%
Planet Labs PBC*		935,837		34,597,894

Semiconductors & Semiconductor Equipment 15.20%
Allegro MicroSystems, Inc.*		381,986		18,526,321
Amkor Technology, Inc.		326,850		22,797,788
Astera Labs, Inc.*		97,006		18,890,948
Credo Technology Group Holding Ltd.*		98,869		17,204,195
Lattice Semiconductor Corp.*		307,882		37,647,811
MACOM Technology Solutions Holdings, Inc.*		183,636		51,713,734
MKS, Inc.		63,491		18,015,571
Nova Ltd. (Israel)*^(b)		88,440		44,258,029
Rambus, Inc.*		161,460		18,585,661
Semtech Corp.*		315,364		33,128,988
SiTime Corp.*		99,838		56,123,932
Total				336,892,978

Software 5.00%
Cipher Digital, Inc.*		922,442		16,364,121
Clear Secure, Inc. Class A		330,272		17,633,222

Investments	Shares		Fair Value
Software (continued)
Guidewire Software, Inc.*		73,700	$	10,199,343
Hut 8 Corp.*		251,529		19,060,868
JFrog Ltd.*		337,654		15,680,652
ServiceTitan, Inc. Class A*		139,225		8,278,318
Terawulf, Inc.*^(a)		1,082,596		23,524,811
Total				110,741,335

Specialty Retail 0.56%
Boot Barn Holdings, Inc.*		72,777		12,477,617
Total Common Stocks (cost $1,438,416,916)				2,210,915,621

		Principal Amount
SHORT-TERM INVESTMENTS 3.44%

REPURCHASE AGREEMENTS 0.53%
Repurchase Agreement dated 4/30/2026, 3.250% due 5/1/2026 with Fixed Income Clearing Corp. collateralized by $11,804,000 of U.S. Treasury Note at 3.750% due 6/30/2027; value: $11,937,853; proceeds: $11,704,778 (cost $11,703,721)	$	11,703,721		11,703,721

TIME DEPOSITS 0.29%
CitiBank N.A.^(c) (cost $6,464,672)		6,464,672		6,464,672

Investments	Shares		Fair Value
MONEY MARKET FUNDS 2.62%
Fidelity Government Portfolio^(c) (cost $58,182,046)		58,182,046	$	58,182,046
Total Short-Term Investments (cost $76,350,439)				76,350,439
Total Investments in Securities 103.20% (cost $1,514,767,355)				2,287,266,060
Other Assets and Liabilities – Net (3.20)%				(70,932,552	)
Net Assets 100.00%			$	2,216,333,508


ADR		American Depositary Receipt.
*		Non-income producing security.
^(a)		All or a portion of this security is temporarily on loan to unaffiliated broker/dealers.
^(b)		Foreign security traded in U.S. dollars.
^(c)		Security was purchased with the cash collateral from loaned securities.

The following is a summary of the inputs used as of April 30, 2026 in valuing the Fund’s investments carried at fair value⁽¹⁾:

A reconciliation of Level 3 investments is presented when the Fund has a material amount of Level 3 investments at the beginning or end of the period in relation to the Fund’s net assets.

Lord Abbett Developing Growth Fund, Inc. (the “Fund”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as a diversified, open-end management investment company. The Fund was incorporated under Maryland law on August 21, 1978. The Fund’s predecessor corporation was organized on July 11, 1973.

Securities actively traded on any recognized U.S. or non-U.S. exchange or on the NASDAQ Stock Market LLC are valued at the last sale price or official closing price on the exchange or system on which they are principally traded. Events occurring after the close of trading on non-U.S. exchanges may result in adjustments to the valuation of foreign securities to reflect their fair value as of the close of regular trading on the New York Stock Exchange. When valuing foreign equity securities that meet certain criteria, the Pricing Committee uses a third-party fair valuation service that values such securities to reflect market trading that occurs after the close of the applicable foreign markets of comparable securities or other instruments that correlate to the fair-valued securities. Unlisted equity securities are valued at the last quoted sale price or, if no sale price is available, at the mean between the most recently quoted bid and ask prices.

Securities for which prices are not readily available are valued at fair value as determined by the Pricing Committee. The Pricing Committee considers a number of factors, including observable and unobservable inputs, when arriving at fair value. The Pricing Committee may use related or comparable assets or liabilities, recent transactions, market multiples, book values, and other relevant information to determine the fair value of portfolio investments. The Board or a designated committee thereof periodically reviews reports that may include fair value determinations made by the Pricing Committee, related market activity, inputs and assumptions, and retrospective comparison of prices of subsequent purchases and sales transactions to fair value determinations made by the Pricing Committee.

Short-term securities with 60 days or less remaining to maturity are valued using the amortized cost method, which approximates fair value. Investments in open-end money market mutual funds are valued at their net asset value as of the close of each business day.

Fair Value Measurements–Fair value is defined as the price that the Fund would receive upon selling an investment or transferring a liability in an orderly transaction to an independent buyer in the principal or most advantageous market of the investment. A three-tier hierarchy is used to maximize the use of observable market data and minimize the use of unobservable inputs and to establish classification of fair value measurements for disclosure purposes. Inputs refer broadly to the assumptions that market participants would use in pricing the asset or liability, including assumptions about risk - for example, the risk inherent in a particular valuation technique used to measure fair value (such as a pricing model) and/or the risk inherent in the inputs to the valuation technique. Inputs may be observable or unobservable. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability. Observable inputs are based on market data obtained from sources independent of the reporting entity. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Unobservable inputs are based on the best information available in the circumstances. The three-tier hierarchy classification is determined based on the lowest level of inputs that is significant to the fair value measurement, and is summarized in the three broad Levels listed below:

A summary of inputs used in valuing the Fund’s investments as of April 30, 2026 and, if applicable, Level 3 rollforwards for the period then ended is included in the Fund’s Schedule of Investments.

Changes in valuation techniques may result in transfers into or out of an assigned level within the three-tier hierarchy. The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those securities.

It is the policy of the Fund to meet the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies and to distribute substantially all taxable income and capital gains to its shareholders. Therefore, no income tax provision is required.

The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund’s filed U.S. federal tax returns remains open generally three years after the filing of the tax return. The statutes of limitations on the Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

The Fund has established a securities lending agreement with Citibank, N.A. for the lending of securities to qualified brokers in exchange for securities or cash collateral equal to at least the market value of securities loaned, plus interest, if applicable. Cash collateral is invested in an approved money market fund. In accordance with the Fund’s securities lending agreement, the market value of securities on loan is determined each day at the close of business and any additional collateral required to cover the value of securities on loan is delivered to the Fund on the next business day. As with other extensions of credit, the Fund may experience a delay in the recovery of its securities or incur a loss should the borrower of the securities breach its agreement with the Fund or the borrower becomes insolvent at a time when the collateral is insufficient to cover the cost of repurchasing securities on loan.

The initial collateral received by the Fund is required to have a value equal to at least 100% of the market value of the securities loaned. The collateral must be marked-to-market daily to cover increases in the market value of the securities loaned (or potentially a decline in the value of the collateral). In general, the risk of borrower default will be borne by Citibank, N.A.; the Fund will bear the risk of loss with respect to the investment of the cash collateral. The advantage of such loans is that the Fund continues to receive income on loaned securities while receiving a portion of any securities lending fees and earning returns on the cash amounts which may be reinvested for the purchase of investments in securities.

As of April 30, 2026, the market value of securities loaned and collateral received were as follows:


⁽¹⁾		Refer to Note 2(a) for a description of fair value measurements and the three-tier hierarchy of inputs.
⁽²⁾		See Schedule of Investments for fair values in each industry and identification of foreign issuers and/or geography. The table above is presented by Investment Type. When applicable, each Level 3 security is identified on the Schedule of Investments along with the valuation technique utilized.

●	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.); and

●	Level 3 –	significant unobservable inputs (including the Fund’s own assumptions in determining the fair value of investments).

Market Value of Securities Loaned	Collateral Received
$67,708,020	$64,646,718

Investment Type⁽²⁾	Level 1		Level 2		Level 3		Total
Long-Term Investments
Common Stocks	$	2,210,915,621	$	–	$	–	$	2,210,915,621
Short-Term Investments
Repurchase Agreements		–		11,703,721		–		11,703,721
Time Deposits		–		6,464,672		–		6,464,672
Money Market Funds		58,182,046		–		–		58,182,046
Total	$	2,269,097,667	$	18,168,393	$	–	$	2,287,266,060


	See Notes to Schedule of Investments.	1


2	See Notes to Schedule of Investments.


	See Notes to Schedule of Investments.	3