SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 31)

First Trust Mortgage Income Fund

(Name of Issuer)

Common Stock

(Title of Class of Securities)

33734E103

(CUSIP Number)

Paul E. Rasmussen
80 South Eighth Street, Suite 3300,
Minneapolis, MN, 55402-4130
612-332-3223

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

12/18/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. Checkbox not checked

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No.

33734E103

Name of reporting person

Sit Investment Associates, Inc.

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

MINNESOTA

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 2,192,343.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 2,192,343.00

Aggregate amount beneficially owned by each reporting person

2,192,343.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

52.0 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

CUSIP No.

33734E103

Name of reporting person

Sit Fixed Income Advisors II, LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 2,192,343.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 2,192,343.00

Aggregate amount beneficially owned by each reporting person

2,192,343.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

52.0 %

Type of Reporting Person (See Instructions)

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Common Stock

(b)

Name of Issuer:

First Trust Mortgage Income Fund

(c)

Address of Issuer's Principal Executive Offices:

120 East Liberty Drive, Suite 400, Wheaton, ILLINOIS , 60187.

Item 1 Comment:

This Amendment No. 31 ("Amendment") amends and supplements the statement on Schedule 13D filed on March 18, 2015, and amended by Amendments No. 1 through No. 30 (as amended, the "Original Schedule 13D" and, as amended by this Amendment, the "Schedule 13D"), relating to the shares of Common Stock ("Shares)" of First Trust Mortgage Income Fund (the "Issuer"). Except as specifically provided herein, each Item of the Original Schedule 13D remains unchanged. Capitalized terms used but not otherwise defined herein have the meanings set forth in the Original Schedule 13D.

Item 5.

Interest in Securities of the Issuer

(a)

The aggregate percentage of Shares reported owned by Sit Entities herein is based upon 4,213,115 Shares outstanding as of April 30, 2025, which is the total number of Shares outstanding as reported in the Issuer's Report on Form N-CSRS filed with the Securities Exchange Commission. As of the date hereof, the Sit Entities may be deemed to be the beneficial owner of 2,192,343 Shares held in client accounts which represent 52.0% of the Issuer's outstanding Shares.

(b)

Each of the Sit Entities may be deemed to have shared power to vote and dispose of such Shares. However, none of SIA's or SFI's directors or executive officers own Shares directly.

(c)

Transactions in Shares by the Sit Entities in the last 60 days are set forth in Exhibit A.

(d)

The clients of SIA and SFI have the right to participate in the receipt of dividends from, or proceeds from the sales of, the Shares held for their respective accounts.

(e)

Not applicable

Item 7.

Material to be Filed as Exhibits.

Exhibit A: Schedule of Transactions in Shares by Sit Entities in the last 60 days.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Sit Investment Associates, Inc.

Signature:	/s/ Roger J. Sit
Name/Title:	Roger J. Sit, Chairman & CEO
Date:	12/23/2025

Sit Fixed Income Advisors II, LLC

Signature:	/s/ Roger J. Sit
Name/Title:	Roger J. Sit, Chairman & CEO
Date:	12/23/2025

Amendment: SEC Form SCHEDULE 13D/A filed by First Trust Mortgage Income Fund