8-K

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

Washington,D.C. 20549

FORM8-K

CURRENTREPORT

Pursuantto Section 13 OR 15(d) of The

SecuritiesExchange Act of 1934

Date of Report (Date of earliest event reported): June 17, 2024

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)

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):

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

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.

SECTION8 – OTHER EVENTS

Item 8.01. OTHER EVENTS

On June 17, 2024 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.

SECTION9 – FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01. FINANCIAL STATEMENTS AND EXHIBITS

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.

Date: June 17, 2024

EXHIBIT INDEX

STRATS TRUST FOR UNITED STATES CELLULAR CORPORATION SECURITIES, SERIES 2004-6 8-k

Exhibit99.1

U.S. Bank Trust National Association, as Trustee for the STRATS TRUST for United States Cellular Corporation Securities, Series 2004-6, hereby gives notice with respect to the Scheduled Distribution Date of June 17, 2024 (the “Distribution Date”) as follows:

U.S. Bank Trust National Association, as Trustee

*The Trustee shall not be held responsible for the selection or use of the CUSIP number nor is any representation made as to its correctness. It is included solely for the convenience of the Holders.