As filed with the Securities and Exchange Commission on September 2, 2015

File No. 001-36869

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 4

to

Form 10

GENERAL FORM FOR REGISTRATION OF SECURITIES

PURSUANT TO SECTION 12(b) OR 12(g) OF

THE SECURITIES EXCHANGE ACT OF 1934

PJT Partners Inc.

(Exact name of registrant as specified in its charter)

280 Park Avenue

New York, NY 10017

(212) 364-7800

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

With copies to:

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

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

None.

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Securities Exchange Act of 1934, as amended. (Check one):

INFORMATION REQUIRED IN REGISTRATION STATEMENT

CROSS-REFERENCE SHEET BETWEEN INFORMATION STATEMENT AND ITEMS OF FORM 10

The information required by this item is contained under the sections “Summary,” “Risk Factors,” “Special Note About Forward-Looking Statements,” “Unaudited Pro Forma Combined Financial Statements,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Business,” “Management,” and “Certain Relationships and Related Party Transactions” of the information statement filed as Exhibit 99.1 to this Form 10 (the “information statement”). Those sections are incorporated herein by reference.

The information required by this item is contained under the section “Risk Factors” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the sections “Summary—Summary Historical and Unaudited Pro Forma Financial Data,” “Capitalization,” “Selected Historical Financial Data,” “Unaudited Pro Forma Combined Financial Statements” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of the information statement. Those sections are incorporated herein by reference.

The information required by this item is contained under the section “Business—Properties” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the section “Security Ownership of Certain Beneficial Owners and Management” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the section “Management” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the section “Management” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the sections “Management” and “Certain Relationships and Related Party Transactions” of the information statement. Those sections are incorporated herein by reference.

i

The information required by this item is contained under the section “Business—Legal Proceedings” of the information statement. That section is incorporated herein by reference.

The information required by this item is contained under the sections “Risk Factors,” “The Spin-Off,” “Dividend Policy,” and “Description of Capital Stock” of the information statement. Those sections are incorporated herein by reference.

Not applicable.

The information required by this item is contained under the sections “Risk Factors—Risks Relating to Our Class A Common Stock,” “Dividend Policy” and “Description of Capital Stock” of the information statement. Those sections are incorporated herein by reference.

The information required by this item is contained under the sections “Certain Relationships and Related Party Transactions—Agreements with Blackstone Related to the Spin-Off—Separation Agreement—Mutual Release and Indemnity,” “Certain Relationships and Related Party Transactions—Indemnification of Directors and Officers” and “Description of Capital Stock—Limitations on Liability and Indemnification of Officers and Directors” of the information statement. Those sections are incorporated herein by reference.

The information required by this item is contained under the sections “Selected Historical Financial Data,” “Unaudited Pro Forma Combined Financial Statements,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Description of Capital Stock,” and “Index to Financial Statements” and the statements referenced therein of the information statement. Those sections are incorporated herein by reference.

None.

The information required by this item is contained under the section “Index to Financial Statements” beginning on page F-1 of the information statement. That section is incorporated herein by reference.

ii

The following documents are filed as exhibits hereto:

iii

SIGNATURES

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: September 2, 2015

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