American Beacon Alpha Quant Core Fund

American Beacon Alpha Quant Dividend Fund

American Beacon Alpha Quant Quality Fund

American Beacon Alpha Quant Value Fund

Supplement dated March 20, 2019

to the

Prospectus and Summary Prospectus dated October 28, 2018

On March 6, 2019, the Board of Trustees of American Beacon Funds (the “Trust”) approved a lower contractual expense limitation for each of the American Beacon Alpha Quant Core Fund, the American Beacon Alpha Quant Dividend Fund, the American Beacon Alpha Quant Quality Fund, and the American Beacon Alpha Quant Value Fund (each a “Fund” and collectively, the “Funds”) effective on or about April 1, 2019. Accordingly, the changes set forth below are effective on or about April 1, 2019:

1.	In the "Fund Summaries – Fees and Expenses of the Fund" section of each Fund, the tables and corresponding footnotes below the first paragraph are deleted and replaced with the following:

A.	American Beacon Alpha Quant Core Fund

Shareholder Fees (fees paid directly from your investment)

Share Class	Y	Institutional	Investor
Maximum sales charge imposed on purchases (as a percentage of offering price)	None	None	None
Maximum deferred sales charge (as a percentage of the lower of original offering price or redemption proceeds)	None	None	None

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Share Class	Y		Institutional		Investor
Management Fee	0.60	%	0.60	%	0.60	%
Distribution and/or Service (12b-1) Fees	0.00	%	0.00	%	0.00	%
Other expenses	5.03	%	4.95	%	6.13	%
Total annual Fund operating expenses	5.63	%	5.55	%	6.73	%
Fee waiver and/or expense reimbursement‌¹	(4.94	%)	(4.96	%)	(5.76	%)
Total Annual Fund Operating Expenses after fee waiver and/or expense reimbursement	0.69	%	0.59	%	0.97	%

1 American Beacon Advisors, Inc. (the "Manager") has contractually agreed to waive fees and/or reimburse expenses of the Fund's Y Class, Institutional Class and Investor Class shares through October 31, 2020 to the extent that Total Annual Fund Operating Expenses exceed 0.69% for the Y Class, 0.59% for the Institutional Class and 97% for the Investor Class (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses, securities lending fees, expenses associated with securities sold short, litigation, and other extraordinary expenses). The contractual expense reimbursement can be changed or terminated only in the discretion and with the approval of a majority of the Fund's Board of Trustees. The Manager can be reimbursed by the Fund for any contractual fee waivers or expense reimbursements if reimbursement to the Manager (a) occurs within three years after the Manager's own waiver or reimbursement and (b) does not cause the Total Annual Fund Operating Expenses of a class to exceed the lesser of the contractual percentage limit in effect at the time of the waiver/reimbursement or the time of the recoupment.

B.	American Beacon Alpha Quant Dividend Fund

Shareholder Fees (fees paid directly from your investment)

Share Class	Y	Institutional	Investor
Maximum sales charge imposed on purchases (as a percentage of offering price)	None	None	None
Maximum deferred sales charge (as a percentage of the lower of original offering price or redemption proceeds)	None	None	None

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Share Class	Y		Institutional		Investor
Management Fee	0.60	%	0.60	%	0.60	%
Distribution and/or Service (12b-1) Fees	0.00	%	0.00	%	0.00	%
Other expenses	5.38	%	5.31	%	6.51	%
Total annual Fund operating expenses	5.98	%	5.91	%	7.11	%
Fee waiver and/or expense reimbursement‌¹	(5.29	%)	(5.32	%)	(6.14	%)
Total Annual Fund Operating Expenses after fee waiver and/or expense reimbursement	0.69	%	0.59	%	0.97	%

1 American Beacon Advisors, Inc. (the "Manager") has contractually agreed to waive fees and/or reimburse expenses of the Fund's Y Class, Institutional Class and Investor Class shares through October 31, 2020 to the extent that Total Annual Fund Operating Expenses exceed 0.69% for the Y Class, 0.59% for the Institutional Class and 0.97% for the Investor Class (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses, securities lending fees, expenses associated with securities sold short, litigation, and other extraordinary expenses). The contractual expense reimbursement can be changed or terminated only in the discretion and with the approval of a majority of the Fund's Board of Trustees. The Manager can be reimbursed by the Fund for any contractual fee waivers or expense reimbursements if reimbursement to the Manager (a) occurs within three years after the Manager's own waiver or reimbursement and (b) does not cause the Total Annual Fund Operating Expenses of a class to exceed the lesser of the contractual percentage limit in effect at the time of the waiver/reimbursement or the time of the recoupment.

C.	American Beacon Alpha Quant Quality Fund

Shareholder Fees (fees paid directly from your investment)

Share Class	Y	Institutional	Investor
Maximum sales charge imposed on purchases (as a percentage of offering price)	None	None	None
Maximum deferred sales charge (as a percentage of the lower of original offering price or redemption proceeds)	None	None	None

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Share Class	Y		Institutional		Investor
Management Fee	0.60	%	0.60	%	0.60	%
Distribution and/or Service (12b-1) Fees	0.00	%	0.00	%	0.00	%
Other expenses	5.18	%	5.09	%	6.23	%
Total annual Fund operating expenses	5.78	%	5.69	%	6.83	%
Fee waiver and/or expense reimbursement‌¹	(5.09	%)	(5.10	%)	(5.86	%)
Total Annual Fund Operating Expenses after fee waiver and/or expense reimbursement	0.69	%	0.59	%	0.97	%

1 American Beacon Advisors, Inc. (the "Manager") has contractually agreed to waive fees and/or reimburse expenses of the Fund's Y Class, Institutional Class and Investor Class shares through October 31, 2020 to the extent that Total Annual Fund Operating Expenses exceed 0.69% for the Y Class, 0.59% for the Institutional Class and 0.97% for the Investor Class (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses, securities lending fees, expenses associated with securities sold short, litigation, and other extraordinary expenses). The contractual expense reimbursement can be changed or terminated only in the discretion and with the approval of a majority of the Fund's Board of Trustees. The Manager can be reimbursed by the Fund for any contractual fee waivers or expense reimbursements if reimbursement to the Manager (a) occurs within three years after the Manager's own waiver or reimbursement and (b) does not cause the Total Annual Fund Operating Expenses of a class to exceed the lesser of the contractual percentage limit in effect at the time of the waiver/reimbursement or the time of the recoupment.

D.	American Beacon Alpha Quant Value Fund

Shareholder Fees (fees paid directly from your investment)

Share Class	Y	Institutional	Investor
Maximum sales charge imposed on purchases (as a percentage of offering price)	None	None	None
Maximum deferred sales charge (as a percentage of the lower of original offering price or redemption proceeds)	None	None	None

Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Share Class	Y		Institutional		Investor
Management Fee	0.60	%	0.60	%	0.60	%
Distribution and/or Service (12b-1) Fees	0.00	%	0.00	%	0.00	%
Other expenses	4.70	%	4.58	%	5.61	%
Total annual Fund operating expenses	5.30	%	5.18	%	6.21	%
Fee waiver and/or expense reimbursement‌¹	(4.61	%)	(4.59	%)	(5.24	%)
Total Annual Fund Operating Expenses after fee waiver and/or expense reimbursement	0.69	%	0.59	%	0.97	%

1 American Beacon Advisors, Inc. (the "Manager") has contractually agreed to waive fees and/or reimburse expenses of the Fund's Y Class, Institutional Class and Investor Class shares through October 31, 2020 to the extent that Total Annual Fund Operating Expenses exceed 0.69% for the Y Class, 0.59% for the Institutional Class and 0.97% for the Investor Class (excluding taxes, interest, brokerage commissions, acquired fund fees and expenses, securities lending fees, expenses associated with securities sold short, litigation, and other extraordinary expenses). The contractual expense reimbursement can be changed or terminated only in the discretion and with the approval of a majority of the Fund's Board of Trustees. The Manager can be reimbursed by the Fund for any contractual fee waivers or expense reimbursements if reimbursement to the Manager (a) occurs within three years after the Manager's own waiver or reimbursement and (b) does not cause the Total Annual Fund Operating Expenses of a class to exceed the lesser of the contractual percentage limit in effect at the time of the waiver/reimbursement or the time of the recoupment.

2.	The "Fund Summaries – Fees and Expenses of the Fund - Example" section is deleted and replaced with the following:

A.	American Beacon Alpha Quant Core Fund

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, except that this Example reflects the fee waiver/expense reimbursement arrangement for each share class through October 31, 2020. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Share Class	1 Year	3 Years	5 Years	10 Years
Y	$ 70	$ 958	$ 2,144	$ 5,044
Institutional	$ 60	$ 931	$ 2,104	$ 4,981
Investor	$ 99	$ 1,156	$ 2,531	$ 5,764

B.	American Beacon Alpha Quant Dividend Fund

Example

Share Class	1 Year	3 Years	5 Years	10 Years
Y	$ 70	$ 1,008	$ 2,257	$ 5,274
Institutional	$ 60	$ 983	$ 2,221	$ 5,220
Investor	$ 99	$ 1,210	$ 2,648	$ 5,988

C.	American Beacon Alpha Quant Quality Fund

Example

Share Class	1 Year	3 Years	5 Years	10 Years
Y	$ 70	$ 979	$ 2,192	$ 5,144
Institutional	$ 60	$ 951	$ 2,150	$ 5,075
Investor	$ 99	$ 1,170	$ 2,562	$ 5,824

D.	American Beacon Alpha Quant Value Fund

Example

Share Class	1 Year	3 Years	5 Years	10 Years
Y	$ 70	$ 910	$ 2,035	$ 4,820
Institutional	$ 60	$ 877	$ 1,982	$ 4,727
Investor	$ 99	$ 1,082	$ 2,367	$ 5,445

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