short_duration_high_yield_fund_summary

SUMMARY PROSPECTUS

Lord Abbett Short Duration High Yield Fund

DECEMBER 1, 2024

CLASS/TICKER

CLASS A ............

LSYAX

CLASS I...........

LSYIX

CLASS R5 .......

LSYTX

CLASS C............

LSYCX

CLASS R2 .......

N/A

CLASS R6 .......

LSYUX

CLASS F ............

LSYFX

CLASS R3 .......

LSYQX

CLASS F3 ..........

LSYNX

CLASS R4 .......

LSYSX

Before you invest, you may want to review the Fund’s prospectus and statement of additional

information, which contain more information about the Fund and its risks. You can find the

Fund’s prospectus, statement of additional information and other information about the Fund at

www.lordabbett.com/documentsandliterature. You can also get this information at no cost by

calling 888-522-2388 (Option #2) or by sending an email request to literature@lordabbett.com.

The current prospectus and statement of additional information dated December 1, 2024 as may

be supplemented from time to time, are incorporated by reference into this summary prospectus.

SUMMARY – Short Duration High Yield Fund

INVESTMENT OBJECTIVE

The Fund’s investment objective is to seek a high current income and the

opportunity for capital appreciation to produce a high total return.

FEES AND EXPENSES

This table describes the fees and expenses that you may pay if you buy, hold, and

sell shares of the Fund.

You may pay other fees, such as brokerage commissions

and other fees to financial intermediaries, which are not reflected in the tables

and examples below.

You may qualify for sales charge discounts if you and certain

members of your family invest, or agree to invest in the future, at least $100,000 in

the Lord Abbett Family of Funds. More information about these and other discounts

is available from your financial intermediary and in “Sales Charge Reductions and

Waivers” on page 82 of the prospectus, Appendix A to the prospectus, titled

“Intermediary-Specific Sales Charge Reductions and Waivers,” and “Purchases,

Redemptions, Pricing, and Payments to Dealers” on page 9-1 of Part II of the

statement of additional information (“SAI”).

Shareholder Fees

(1)

(Fees paid directly from your investment)

Class

F, F3, I, R2, R3, R4, R5, and R6

Maximum Sales Charge (Load) Imposed on Purchases

(as a percentage of offering price)

2.25%

None

Maximum Deferred Sales Charge (Load)

(as a percentage of offering price or redemption

proceeds, whichever is lower)

None

(2)

1.00%

(3)

None

Annual Fund Operating Expenses

(Expenses that you pay each year as a percentage of the value of your investment)

Class

Management Fees

0.32%

Distribution and Service (12b-1) Fees

0.20%

0.92%

(4)

0.10%

None

Other Expenses

0.19%

0.11%

0.19%

Total Annual Fund Operating Expenses

0.71%

1.43%

0.61%

0.43%

0.51%

Fee Waiver and/or Expense Reimbursement

(5)

(0.06)%

(0.16)%

(6)

(0.06)%

Total Annual Fund Operating Expenses After Fee Waiver

and/or Expense Reimbursement

(5)

0.65%

1.37%

0.45%

0.37%

0.45%

SUMMARY – Short Duration High Yield Fund

Annual Fund Operating Expenses

(continued)

(Expenses that you pay each year as a percentage of the value of your investment)

Class

Management Fees

0.32%

Distribution and Service (12b-1) Fees

0.60%

0.50%

0.25%

None

Other Expenses

0.19%

0.11%

Total Annual Fund Operating Expenses

1.11%

1.01%

0.76%

0.51%

0.43%

Fee Waiver and/or Expense Reimbursement

(5)

(0.06)%

Total Annual Fund Operating Expenses After Fee Waiver and/or

Expense Reimbursement

(5)

1.05%

0.95%

0.70%

0.45%

0.37%

(1)

A shareholder transacting in share classes without a front-end sales charge may be required to pay a commission to its

financial intermediary. Please contact your financial intermediary for more information about whether such a commission

may apply to your transaction.

(2)

A contingent deferred sales charge (“CDSC”) of 1.00% may be assessed on certain Class A shares purchased or

acquired without a sales charge if they are redeemed before the first day of the month in which the one-year anniversary

of the purchase falls.

(3)

A CDSC of 1.00% may be assessed on Class C shares if they are redeemed before the first anniversary of their

purchase.

(4)

The 12b-1 fee the Fund will pay on Class C shares will be a blended rate calculated based on (i) 1.00% of the Fund’s

average daily net assets attributable to shares held for less than one year and (ii) 0.80% of the Fund’s average daily net

assets attributable to shares held for one year or more. All Class C shareholders of the Fund will bear 12b-1 fees at the

same rate.

(5)

For the period from December 1, 2024 through November 30, 2025, Lord, Abbett & Co. LLC (“Lord Abbett”) has

contractually agreed to waive its fees and reimburse expenses to the extent necessary to limit total net annual operating

expenses, excluding any applicable 12b-1 fees, acquired fund fees and expenses, interest-related expenses, taxes,

expenses related to litigation and potential litigation, and extraordinary expenses, to an annual rate of 0.37% for each of

Class F3 and R6 shares and to an annual rate of 0.45% for each other class. This agreement may be terminated only by

the Fund’s Board of Trustees.

(6)

For the period from December 1, 2024 through November 30, 2025, Lord Abbett Distributor LLC (“Lord Abbett

Distributor”) has contractually agreed to waive the Fund’s 0.10% Rule 12b-1 fee for Class F shares. This agreement may

be terminated only by the Fund’s Board of Trustees.

Example

This Example 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 for the time periods indicated and then redeem all of your shares

at the end of those periods. The Example also assumes that your investment has a

5% return each year and that the Fund’s operating expenses remain the same, giving

effect to the fee waiver and expense reimbursement arrangement described above.

Class C shares automatically convert to Class A shares after eight years. The

expense example for Class C shares for the ten-year period reflects the conversion to

Class A shares. Although your actual costs may be higher or lower, based on these

assumptions your costs would be: