UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 16, 2025

SYNTHETIC FIXED-INCOME SECURITIES, INC. ON BEHALF OF:

STRATS TRUST FOR UNITED STATES CELLULAR CORPORATION SECURITIES, SERIES 2004-6

(Exact name of registrant as specified in its charter)

Delaware

333-111858-01

001-32156

52-2316339

(State or other jurisdiction of incorporation)

(Commission File Number)

(I.R.S. Employer Identification No.)

Synthetic Fixed Income Securities, Inc.
301 South College
Charlotte, North Carolina	28288
(Address of principal executive offices)	(Zip Code)

Registrant's telephone number, including area code: (212) 214-6277

No Change

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
STRATS Certificates, Series 2004-6	N/A	New York Stock Exchange (“NYSE”)

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐

The STRATS TRUST For United States Cellular Corporation Securities, Series 2004-6, which we refer to herein as the “Trust,” was formed pursuant to the Base Trust Agreement, dated as of September 26, 2003, between Synthetic Fixed-Income Securities, Inc., as depositor, and U.S. Bank Trust National Association, as trustee and securities intermediary, as supplemented by the STRATS Certificates Series Supplement 2004-6 in respect of the Trust dated as of April 21, 2004.

SECTION 8 – OTHER EVENTS

Item 8.01. OTHER EVENTS

On June 16, 2025 distribution was made to the holders of the certificates issued by the Trust. Specific information with respect to the distribution is filed as Exhibit 99.1 hereto.

No other reportable transactions or matters have occurred during the current reporting period.

United States Cellular Corporation, the issuer of the underlying securities,the sole assets held by the Trust, is subject to the information reporting requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). For information on United States Cellular Corporation please see its periodic and current reports filed with the Securities and Exchange Commission (the “Commission”) under its Exchange Act file number, 001-09712. The Commission maintains a site on the World Wide Web at “http://www.sec.gov” at which users can view and download copies of reports, proxy and information statements and other information filed electronically through the Electronic Data Gathering, Analysis and Retrieval system, or “EDGAR.” Periodic and current reports and other information required to be filed pursuant to the Exchange Act by United States Cellular Corporation may be accessed on this site. Neither Synthetic Fixed-Income Securities, Inc. nor the Trustee has participated in the preparation of such reporting documents, or made any due diligence investigation with respect to the information provided therein. Neither Synthetic Fixed-Income Securities, Inc. nor the Trustee has verified the accuracy or completeness of such documents or reports. There can be no assurance that events affecting the issuer of the underlying securities or the underlying securities themselves have not occurred or have not yet been publicly disclosed which would affect the accuracy or completeness of the publicly available documents described above.

SECTION 9 – FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01. FINANCIAL STATEMENTS AND EXHIBITS

(d)	The following exhibit is filed as part of this report:

99.1	Trustee’s Distribution Statement to the STRATS Certificates, Series 2004-6 for June 16, 2025 Scheduled Distribution Date.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	Synthetic Fixed-Income Securities, Inc.

	By:	/s/ Barbara Garafalo
	Name:	Barbara Garafalo
	Title:	President
Date: June 16, 2025

EXHIBIT INDEX

Exhibit Number

Description

99.1

Trustee’s Distribution Statement to the STRATS Certificates, Series 2004-6 for June 16, 2025 Scheduled Distribution Date.

STRATS SM TRUST FOR U S CELL CORP SEC SERIES 2004 6 8-K