UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 10-K





(Mark One)

|☒ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------

For the fiscal year ended December 31, 2017

or



|☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ----------------------------------------------------------------------------------------

For the transition period from
 to

333-166711-02

(Commission File Number of issuing entity)

0001556811

(Central Index Key Number of issuing entity)

Citigroup Commercial Mortgage Trust 2012-GC8

(Exact name of issuing entity as specified in its charter)

333-166711

(Commission File Number of depositor)

0001258361

(Central
Index Key Number of depositor)

Citigroup Commercial Mortgage Securities Inc.

(Exact name of depositor as specified in its charter)

Citigroup Global Markets Realty Corp.

(Central Index Key Number: 0001541001)

Goldman Sachs Mortgage Company

(Central Index Key Number: 0001541502)

Natixis Real Estate Capital LLC

(Central Index Key Number: 0001542256)

(Exact name of sponsor as specified in its charter)



|                                                                    |  |                                     
|------------------------------------------------------------------- |  | ------------------------------------
|                                                                    |  | 90-6223187                          
|                                                                    |  | 90-6223322                          
|New York                                                            |  | 90-6223352                          
|(State or other jurisdiction of
organization of the issuing entity) |  | (I.R.S. Employer
Identification No.)

c/o Citibank, N.A.

388 Greenwich Street, 14th Floor

New York, New York 10013

(Address of principal executive offices of issuing entity)

(212) 816-5614

Registrants telephone number, including area code

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

None

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

None





Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities
Act.    ☐  Yes    ☒  No

Indicate by check mark if the registrant is not required
to file reports pursuant to Section 13 or Section 15(d) of the Act.    ☐  Yes    ☒  No

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act
of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90
days.    ☒  Yes    ☐  No

Indicate by check mark whether the registrant has
submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter)
during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).

Not Applicable

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405
of this chapter) is not contained herein, and will not be contained, to the best of registrants knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form
10-K or any amendment to this Form 10-K.

Not Applicable

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company,
or an emerging growth company. See the definitions of large accelerated filer, accelerated filer, smaller reporting company, and emerging growth company in Rule 12b-2 of the Exchange Act.



|                        |  |   |  |                                               |  |                           |  |  
|----------------------- |  | - |  | --------------------------------------------- |  | ------------------------- |  | -
|Large accelerated filer |  | ☐ |  |                                               |  | Accelerated filer         |  | ☐
|                        |  |   |  |                                              
|Non-accelerated filer   |  | ☒ |  | (Do not check if a smaller reporting company) |  | Smaller reporting company |  | ☐
|                        |  |   |  |                                              
|                        |  |   |  |                                               |  | 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.    ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the
Act).    ☐  Yes    ☒  No

State the aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold, or the average bid and asked price of such common
equity, as of the last business day of the registrants most recently completed second fiscal quarter.

Not Applicable

Indicate by check mark whether the registrant has filed all documents and reports required to be filed by Section 12, 13 or 15(d) of the Securities
Exchange Act of 1934 subsequent to the distribution of securities under a plan confirmed by a court.

Not Applicable

Indicate the number of shares outstanding of each of the registrants classes of common stock, as of the latest practicable date.

Not Applicable









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DOCUMENTS INCORPORATED BY REFERENCE

List hereunder the following documents if incorporated by reference and the Part of the Form 10-K (e.g., Part I, Part
II, etc.) into which the document is incorporated: (1) Any annual report to security holders; (2) Any proxy or information statement; and (3) Any prospectus filed pursuant to Rule 424(b) or (c) under the Securities Act of 1933.
The listed documents should be clearly described for identification purposes (e.g., annual report to security holders for fiscal year ended December 24, 1980).

See Item 15.

PART I

Item 1. Business.

Omitted.

Item 1A. Risk Factors.

Omitted.

Item 1B. Unresolved Staff Comments.

None.

Item 2. Properties.

Omitted.

Item 3. Legal Proceedings.

Omitted.

Item 4. Mine Safety Disclosures.

Not applicable.

PART II

Item 5. Market for
Registrants Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Omitted.

Item 6. Selected Financial Data.

Omitted.

Item 7. Managements Discussion and Analysis of Financial Condition and Results of Operations.

Omitted.

Item 7A. Quantitative and Qualitative
Disclosures About Market Risk.

Omitted.

Item 8.
Financial Statements and Supplementary Data.

Omitted.



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Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

Omitted.

Item 9A. Controls and Procedures.

Omitted.

Item 9B. Other Information.

None.

PART III

Item 10. Directors, Executive Officers and Corporate Governance.

Omitted.

Item 11. Executive Compensation.

Omitted.

Item 12. Security Ownership of Certain Beneficial
Owners and Management and Related Stockholder Matters.

Omitted.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

Omitted.

Item 14. Principal Accounting Fees and Services.

Omitted.

ADDITIONAL
DISCLOSURE ITEMS REQUIRED BY GENERAL INSTRUCTION J(2)

Item 1112(b) of Regulation AB

The property securing the Miami Center mortgage loan constitutes a significant obligor within the meaning of Item 1101(k)(2) of Regulation AB and as disclosed
in the prospectus supplement for Citigroup Commercial Mortgage Trust 2012-GC8 filed on September 24, 2012. With respect to the property securing the Miami Center mortgage loan, the most recent unaudited
net operating income was $12,454,728 for the period from January 1, 2017 through December 31, 2017.

Item 1114(b)(2) and Item 1115(b) of
Regulation AB

No entity or group of affiliated entities provides any external credit enhancement, uses any derivative instruments or other support for
the certificates within this transaction.

Item 1117 of Regulation AB

Disclosure from Citibank, N.A., as Certificate Administrator:

Citibank, N.A. (Citibank) is acting as the Certificate Administrator of this commercial mortgage-backed securities (CMBS) transaction.
In the ordinary course of business, Citibank is involved in a number of legal proceedings, including in connection with its role as trustee of certain residential mortgage-backed securities (RMBS) transactions. Certain of these Citibank
as trustee-related matters are disclosed herein.

On June 18, 2014, a civil action was filed against Citibank in the Supreme Court of the State of
New York by a group of investors in 48 private-label RMBS trusts for which Citibank allegedly serves or did serve as trustee, asserting claims for purported violations of the U.S. Trust Indenture Act of 1939, as amended (the Trust Indenture
Act), breach of contract, breach of fiduciary duty and negligence based on Citibanks alleged failure to perform its duties as trustee for the 48 RMBS trusts. On November 24, 2014, plaintiffs sought leave to withdraw this action. On
the same day, a smaller subset of similar plaintiff investors in 27 private-label RMBS trusts for which Citibank allegedly serves or did serve as trustee, filed a new civil action against Citibank in the United States District Court for the Southern
District of New York asserting similar claims as the prior action filed in state court. In January 2015, the court closed plaintiffs original state court action. On September 8, 2015, the federal court dismissed all claims as to 24 of the
27



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trusts and allowed certain of the claims to proceed as to the other three trusts. Subsequently, plaintiffs voluntarily dismissed all claims with respect to two of the three trusts. On
April 7, 2017, Citibank filed a motion for summary judgment. Plaintiffs filed its consolidated opposition brief and cross motion for partial summary judgment on May 22, 2017. Briefing on those motions was completed on August 4, 2017.

On November 24, 2015, the same investors that brought the federal case brought a new civil action in the Supreme Court of the State of New York
related to 25 private-label RMBS trusts for which Citibank allegedly serves or did serve as trustee. This case includes the 24 trusts previously dismissed in the federal action, and one additional trust. The investors assert claims for breach of
contract, breach of fiduciary duty, breach of duty to avoid conflicts of interest, and violation of New Yorks Streit Act (the Streit Act). Following oral argument on Citibanks motion to dismiss, plaintiffs filed an amended
complaint on August 5, 2016. On June 27, 2017, the state court issued a decision, dismissing the event of default claims, mortgage-file-related claims, the fiduciary duty claims, and the conflict of interest claims. The decision sustained
certain breach of contract claims including the claim alleging discovery of breaches of representations and warranties, a claim related to robo-signing, and the implied covenant of good faith claim. Citibank appealed the lower courts decision,
and on January 16, 2018, the Appellate Division, First Department, dismissed the claims related to robo-signing and the implied covenant of good faith, but allowed plaintiffs claim alleging discovery of breaches of representations and
warranties to proceed.

On August 19, 2015, the Federal Deposit Insurance Corporation (FDIC) as receiver for a failed financial
institution filed a civil action against Citibank in the Southern District of New York. This action relates to one private-label RMBS trust for which Citibank formerly served as trustee. FDIC asserts claims for breach of contract, violation of the
Streit Act, and violation of the Trust Indenture Act. Citibank jointly briefed a motion to dismiss with The Bank of New York Mellon and U.S. Bank, N.A., entities that have also been sued by FDIC in their capacity as trustee, and these cases have all
been consolidated in front of Judge Carter. On September 30, 2016, the court granted Citibanks motion to dismiss the complaint without prejudice for lack of subject matter jurisdiction. On October 14, 2016, FDIC filed a motion for
reargument or relief from judgment from the courts dismissal order. On July 11, 2017, Judge Carter ruled on the motion for reconsideration regarding his dismissal of the action. He denied reconsideration of his decision on standing, but
granted leave to amend the complaint by October 9, 2017. The FDIC subsequently requested an extension of time to file its amended complaint, which was granted. The FDIC filed its amended complaint on December 8, 2017.

There can be no assurances as to the outcome of litigation or the possible impact of litigation on the trustee or the RMBS trusts. However, Citibank denies
liability and continues to vigorously defend against these litigations. Furthermore, neither the above-disclosed litigations nor any other pending legal proceeding involving Citibank will materially affect Citibanks ability to perform its
duties as Certificate Administrator under the pooling and servicing agreement for this CMBS transaction.

Item 1119 of Regulation AB

Provided previously in the prospectus supplement of the Registrant relating to the issuing entity and filed on September 24, 2012 pursuant to Rule
424(b)(5) of the Securities Act of 1933, as amended.

Item 1122 of Regulation AB

The reports on assessment of compliance with servicing criteria for asset-backed securities and related attestation reports are attached hereto under Item 15.

Item 1123 of Regulation AB

The servicer
compliance statements are attached hereto under Item 15.

PART IV

Item 15. Exhibits, Financial Statement Schedules.



|(a) | List the following documents filed as a part of the report:
|--- | -----------------------------------------------------------



| | (1) | Not Applicable
| | --- | --------------



| | (2) | Not Applicable
| | --- | --------------



---

| | (3) | Exhibits listed below are either included or incorporated by reference as indicated below:
| | --- | ------------------------------------------------------------------------------------------



|               |  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|-------------- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Exhibit Number |  | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|               | 
|4              |  | Pooling and Servicing Agreement, dated as of September 
1, 2012, by and among Citigroup Commercial Mortgage Securities Inc., as depositor, Wells Fargo Bank, National Association, as master servicer, LNR Partners, LLC (as successor to Midland Loan Services, a Division of PNC Bank, National Association), as special
servicer, Situs Holdings, LLC, as operating advisor, Citibank, N.A., as certificate administrator, and U.S. Bank National Association, as trustee (filed as Exhibit 4 to the registrants Current Report on Form
8-K/A dated September 24, 2012, and filed by the registrant on October 1, 2012 under Commission File
No. 333-166711-02, and is incorporated by reference herein).
|               | 
|10.1           |  | Mortgage Loan Purchase Agreement, dated as of September 
1, 2012, between Citigroup Global Markets Realty Corp. and Citigroup Commercial Mortgage Securities Inc., pursuant to which Citigroup Global Markets Realty Corp. sold certain mortgage loans to the depositor (filed as Exhibit 10.1 to the registrants
 Current Report on Form 8-K/A dated September 24, 2012, and filed by the registrant on October 1, 2012 under Commission File
No. 333-166711-02, and is incorporated by reference herein).                                                                                                                                                                                                 
|               | 
|10.2           |  | Mortgage Loan Purchase Agreement, dated as of September 
1, 2012, between Goldman Sachs Mortgage Company and Citigroup Commercial Mortgage Securities Inc., pursuant to which Goldman Sachs Mortgage Company sold certain mortgage loans to the depositor (filed as Exhibit 10.2 to the registrants Current Report
 on Form 8-K/A dated September 24, 2012, and filed by the registrant on October 1, 2012 under Commission File
No. 333-166711-02, and is incorporated by reference herein).                                                                                                                                                                                                               
|               | 
|10.3           |  | Mortgage Loan Purchase Agreement, dated as of September 
1, 2012, between Natixis Real Estate Capital LLC and Citigroup Commercial Mortgage Securities Inc., pursuant to which Natixis Real Estate Capital LLC sold certain mortgage loans to the depositor (filed as Exhibit 10.3 to the registrants Current Report
on Form 8-K/A dated September 24, 2012, and filed by the registrant on October 1, 2012 under Commission File
No. 333-166711-02, and is incorporated by reference herein).                                                                                                                                                                                                              
|               | 
|31             |  | Rule 15d-14(d) Certification                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|               | 
|33             |  | Reports on assessment of compliance with servicing criteria for asset-backed securities.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|               | 
|33.1           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, Wells Fargo Bank, National Association, as master servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|               | 
|33.2           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, LNR Partners, LLC, as special servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|               | 
|33.3           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, Situs Holdings, LLC, as operating advisor                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|               | 
|33.4           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, Citibank, N.A., as certificate administrator                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|               | 
|33.5           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, U.S. Bank National Association, as custodian                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|               | 
|33.6           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, CoreLogic Commercial Real Estate Services, Inc., as servicing function participant                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|               | 
|33.7           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, National Tax Search, LLC, as servicing function participant                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|               | 
|33.8           |  | Report on assessment of compliance with servicing criteria for asset-backed securities, Northmarq Capital, LLC, as servicing function participant                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|               | 
|34             |  | Attestation reports on assessment of compliance with servicing criteria for asset-backed securities.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|               | 
|34.1           |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, Wells Fargo Bank, National Association, as master servicer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               



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|     |  |                                                                                                                                                                                       
|---- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|     | 
|34.2 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, LNR Partners, LLC, as special servicer                                            
|     | 
|34.3 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, Situs Holdings, LLC, as operating advisor                                         
|     | 
|34.4 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, Citibank, N.A., as certificate administrator                                      
|     | 
|34.5 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, U.S. Bank National Association, as custodian                                      
|     | 
|34.6 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, CoreLogic Commercial Real Estate Services, Inc., as servicing function participant
|     | 
|34.7 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, National Tax Search, LLC, as servicing function participant                       
|     | 
|34.8 |  | Attestation report on assessment of compliance with servicing criteria for asset-backed securities, Northmarq Capital, LLC, as servicing function participant                         
|     | 
|35   |  | Servicer compliance statements.                                                                                                                                                       
|     | 
|35.1 |  | Servicer compliance statement, Wells Fargo Bank, National Association, as master servicer                                                                                             
|     | 
|35.2 |  | Servicer compliance statement, LNR Partners, LLC, as special servicer                                                                                                                 
|     | 
|35.3 |  | Servicer compliance statement, Citibank, N.A., as certificate administrator                                                                                                           

|(b) | The exhibits required to be filed by Registrant pursuant to Item 601 of Regulation S-K are listed above.
|--- | --------------------------------------------------------------------------------------------------------



|(c) | Not Applicable
|--- | --------------



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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

Date: March 30, 2018



|                                             
|---------------------------------------------
|Citigroup Commercial Mortgage Securities Inc.
|(Depositor)                                  
|                                             
|/s/ Paul Vanderslice                         
|Paul Vanderslice, President