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

September 17, 2025
Date of Report (Date of Earliest Event Reported)

Central Index Key Number of the issuing entity: 0001716263
UBS Commercial Mortgage Trust 2017-C4
(Exact name of issuing entity)

Central Index Key Number of the registrant: 0001532799
UBS Commercial Mortgage Securitization Corp.
(Exact name of registrant as specified in its charter)

Central Index Key Number of the sponsor: 0001685185
UBS AG
(Exact name of sponsor as specified in its charter)

Central Index Key Number of the sponsor: 0001238163
Société Générale, New York Branch
(Exact name of sponsor as specified in its charter)

Central Index Key Number of the sponsor: 0001541468
Ladder Capital Finance LLC
(Exact name of sponsor as specified in its charter)

Central Index Key Number of the sponsor: 0001592182
LMF Commercial, LLC (formerly known as Rialto Mortgage Finance, LLC)
(Exact name of sponsor as specified in its charter)

Central Index Key Number of the sponsor: 0001548567
CIBC Inc.
(Exact name of sponsor as specified in its charter)

Central Index Key Number of the sponsor: 0001542256
Natixis Real Estate Capital LLC
(Exact name of sponsor as specified in its charter)

New York		333-207340-04		38-4046694 38-4046695 38-7187327
(State or other jurisdiction of incorporation of issuing entity)		(Commission File Number of issuing entity)		(I.R.S. Employer Identification Numbers)

c/o Computershare Trust Company, N.A., as agent for
Wells Fargo Bank, National Association
9062 Old Annapolis Road
Columbia, MD 21045
(Address of principal executive offices of the issuing entity) (Zip Code)

(212) 713-8832
Registrant's Telephone number, including area code

Former name or former address, if changed since last report: Not Applicable

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:

☐ 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

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.

Item 8.01 Other Events.

The JW Marriott Chicago Mortgage Loan, which constituted approximately 1.3% of the asset pool of the issuing entity as of its cut-off date, is an asset of the issuing entity and is part of a loan combination that is being serviced and administered under the pooling and servicing agreement, dated as of September 1, 2017, relating to the CSAIL 2017-CX9 Commercial Mortgage Trust, filed as Exhibit 4.5 to the registrant’s Current Report on Form 8-K filed on October 18, 2017 (the “CSAIL 2017-CX9 PSA”). Pursuant to Section 7.01(d) of the CSAIL 2017-CX9 PSA, Rialto Capital Advisors, LLC, a Delaware limited liability company, was removed as special servicer of the JW Marriott Chicago Mortgage Loan and Torchlight Loan Services, LLC (“Torchlight”), a Delaware limited liability company, was appointed as the successor special servicer of the JW Marriott Chicago Mortgage Loan under the CSAIL 2017-CX9 PSA.

In the interest of transaction management, this Current Report on Form 8-K is being filed to record that, effective as of September 17, 2025, the JW Marriott Chicago Mortgage Loan will be specially serviced, if necessary, pursuant to the CSAIL 2017-CX9 PSA, by Torchlight. Torchlight maintains its principal special servicing office at 90 Park Avenue, 20th Floor, New York, New York 10016 and its telephone number is 212-883-2800.

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.

UBS Commercial Mortgage Securitization Corp.
(Depositor)

/s/ Nicholas Galeone
Nicholas Galeone, President

Date: September 17, 2025

/s/ Andrew Lisa
Andrew Lisa, Executive Director

Date: September 17, 2025

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

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington D.C. 20549

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UBS Commercial Mortgage Trust 2017-C4 8-K