CBAY Cymabay Therapeutics Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 2)*

CymaBay Therapeutics, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value

(Title of Class of Securities)

23257D103

(CUSIP Number)

December 31, 2023

(Date of Event Which Requires Filing of This Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☒ Rule 13d-1(c)

☐ Rule 13d-1(d)

The information required in 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).

Explanatory Note

This Amendment No. 2 (“Amendment No. 2”) amends and supplements the Schedule 13G initially filed with the Securities and Exchange Commission (the “Commission”) on November 29, 2021, as amended by Amendment No. 1 filed with the Commission on February 14, 2023 (collectively, the “Original Schedule 13G”) and is being filed by TCG Crossover Fund I, L.P. (“TCG Crossover I”), TCG Crossover GP I, LLC (“TCG Crossover GP I” and together with TCG Crossover I, the “Reporting Entities”) and Chen Yu (the “Reporting Individual”). The Reporting Entities and the Reporting Individual are collectively referred to as the “Reporting Persons.” The agreement among the Reporting Persons to file jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Act is filed as Exhibit 1 to the Original Schedule 13G. Only those items that are hereby reported are amended; all other items reported in the Original Schedule 13G remain unchanged. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable. Capitalized terms not defined in this Amendment No. 2 have the meanings ascribed to them in the Original Schedule 13G.

(a) Amount beneficially owned:

See Row 9 of the cover page for each Reporting Person.*

(b) Percent of class:

See Row 11 of the cover page for each Reporting Person.*

(c) Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote

See Row 5 of the cover page for each Reporting Person.*

(ii) Shared power to vote or to direct the vote

See Row 6 of the cover page for each Reporting Person.*

(iii) Sole power to dispose or to direct the disposition of

See Row 7 of the cover page for each Reporting Person.*

(iv) Shared power to dispose or to direct the disposition of

See Row 8 of the cover page for each Reporting Person.*

If this statement is being filed to report the fact that as of the date hereof the Reporting Persons have ceased to be the beneficial owner of more than 5% of the class of securities, check the following: ☒

Material to be Filed as Exhibits.

Exhibit 24 – Power of Attorney (Craig Skaling).

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.

Dated: February 13, 2024

Exhibit 24

POWER OF ATTORNEY

KNOW ALL BY THESE PRESENTS, that each of the undersigned hereby constitutes and appoints Craig Skaling as the undersigned’s true and lawful attorney-in-fact (the “Attorney-in-Fact”) to:

The undersigned hereby grants to the Attorney-in-Fact full power and authority to do and perform all and every act and thing whatsoever requisite, necessary, and proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that the Attorney-in-Fact, or her substitute or substitutes, shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 3, 4 and 5, Form 13F or Schedules 13G/D with respect to the undersigned’s holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Attorney-in-Fact. The Reporting Person acknowledges that the Attorney-in-Fact, in serving in such capacity at the request of the undersigned, is not hereby assuming any of the undersigned’s responsibilities to comply with Section 13 or Section 16 of the Securities Exchange Act of 1934 and state or federal securities laws. This Power of Attorney may be filed with the Commission as a confirming statement of the authority granted herein.

[SIGNATURES ON THE FOLLOWING PAGE.]

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this February 8, 2024.