**UNITED STATESSECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 10-K**

(Mark One)

**x****  ANNUAL REPORT PURSUANT TO SECTION13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934**

**For the fiscal year ended December 31, 2021or**

**o**** ****TRANSITIONREPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934**

**For the transition period from _____ to _____Commission file number of the issuing entity: 333-206703-01**

**Central Index Key Number of the issuing entity:0001655153**

**CSAIL 2015-C4 Commercial MortgageTrust**

**(exact name of the issuing entity as specified in itscharter)**

** **

**Central Index Key Number of the depositor: 0000802106**

**Credit Suisse First Boston MortgageSecurities Corp.**

**(exact name of the depositor as specified in its charter)**

** **

**Central Index Key Number of the sponsor: 0001628601**

**Column Financial, Inc.**

**(exact name of the sponsor as specified in its charter)**

** **

**Central Index Key Number of the sponsor: 0001632269**

**Benefit Street Partners CRE FinanceLLC**

**(exact name of the sponsor as specified in its charter)**

** **

**Central Index Key Number of the sponsor: 0001666643**

**Walker & Dunlop CommercialProperty Funding I CS, LLC**

**(exact name of the sponsor as specified in its charter)**

** **

**Central Index Key Number of the sponsor: 0001505494**

**The Bancorp Bank**

**(exact name of the sponsor as specified in its charter)**

** **

**Central Index Key Number of the sponsor: 0001576832**

**MC-Five Mile Commercial MortgageFinance LLC**

**(exact name of the sponsor as specified in its charter)**

** **

| **New York****(State or other jurisdiction of  incorporation or organization of**

**the issuing entity)** | **38-3984607**

**38-3984608**

**(I.R.S. Employer**

**Identification Numbers)** |
|------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------|

**c/o Wells Fargo Bank, National Association**

**as Certificate Administrator**

**9062 Old Annapolis Road**

**Columbia, MD**

**(Address of principalexecutive offices of the issuing entity)**

**21045**

**(Zip Code)**

**Registrant’s telephone number,including area code:**

**(212) 272-6858**

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

| Title of each class | Trading Symbol(s) | Name of each exchange  on which registered |
|---------------------|-------------------|--------------------------------------------|
| None                |              |                                       |

Securities registered pursuant to Section 12(g) of theAct:  None.

Indicate by check mark if the registrant is a well-knownseasoned issuer, as defined in Rule 405 of the Securities Act.  o Yes ⌧No

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

Indicate by check mark whether the registrant (1) has filedall reports required to be filed by Section 13 or 15(d) of the Securities ExchangeAct of 1934 during the preceding 12 months (or for such shorter period that theregistrant was required to file such reports), and (2) has been subject to suchfiling requirements for the past 90 days.  ⌧Yes oNo

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

Not applicable.

Indicate by check mark if disclosure of delinquent filerspursuant to Item 405 of Regulation S-K (Section 229.405 of this chapter) is notcontained herein, and will not be contained, to the best of registrant’sknowledge, in definitive proxy or information statements incorporated byreference in Part III of this Form 10-K or any amendment to this Form10-K.   

Not applicable.

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

Large acceleratedfiler        o                                                                                                       Acceleratedfiler                                     o

Non-acceleratedfiler          ⌧  (Do not check if asmaller reporting company)                          Smaller reporting company                    o

                                                                                                                                                       Emerging growth company                    o

If an emerging growth company, indicate by check mark if theregistrant has elected not to use the extended transition period for complyingwith any new or revised financial accounting standards provided pursuant toSection 13(a) of the Exchange Act.  o

Indicate by check mark whether the registrant has filed areport on and attestation to its management’s assessment of the effectivenessof its internal control over financial reporting under Section 404(b) of theSarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firmthat prepared or issued its audit report. o

Indicate by check mark whether the registrant is a shellcompany (as defined in Rule 12b-2 of the Act).  o Yes ⌧ No

State the aggregate market value of the voting and non-votingcommon equity held by non-affiliates computed by reference to the price atwhich the common equity was last sold, or the average bid and asked price ofsuch common equity, as of the last business day of the registrant’s mostrecently completed second fiscal quarter.

Not applicable.

Indicate by check mark whether the registrant has filed alldocuments and reports required to be filed by Section 12, 13 or 15(d) of theSecurities Exchange Act of 1934 subsequent to the distribution of securitiesunder a plan confirmed by a court.  oYes oNo

Not applicable.

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

Not applicable.

**DOCUMENTS INCORPORATED BY REFERENCE**

** **

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

Not applicable.

 

** **

**EXPLANATORY NOTES**

The Exhibit Index describesexhibits provided by certain parties (in their capacities indicated on theExhibit Index) with respect to the Arizona Grand Resort & Spa MortgageLoan, which constituted approximately 4.8% of the asset pool of the issuingentity as of its cut-off date.  The Arizona Grand Resort & SpaMortgage Loan is an asset of the issuing entity and is part of a loancombination that includes the Arizona Grand Resort & Spa Mortgage Loan andone other *pari passu* loan, which is not an asset of the issuing entity.The other *pari passu* portion of the loan combination was securitized inthe CSAIL 2015-C3 Commercial Mortgage Trust transaction, Commission File Number333-199921-03 (the “CSAIL 2015-C3 Transaction”). This loan combination,including the Arizona Grand Resort & Spa Mortgage Loan, is being servicedand administered pursuant to the pooling and servicing agreement for the CSAIL2015-C3 Transaction, which is incorporated by reference as Exhibit 4.2 to thisAnnual Report on Form 10-K.

The master servicer of a poolingand servicing agreement or trust and servicing agreement also functions as theprimary servicer of the related mortgage loans serviced and administeredpursuant to such agreement unless a separate primary servicer is identifiedherein.  If this report does not identify a separate primary servicer, theservicer compliance statement provided by the master servicer under any suchagreement also encompasses its responsibilities as primary servicer of therelated mortgage loan or mortgage loans.

Wells Fargo Bank, National Association is the custodian ofthe mortgage loans serviced under the Pooling and Servicing Agreement and theArizona Grand Resort & Spa Mortgage Loan.  As a result, Wells FargoBank, National Association is a servicing function participant in thecapacities described above, because it is servicing mortgage loans thatconstituted 5% or more of the assets of the issuing entity as of its cut-offdate. The assessments of compliance with applicable servicing criteria andaccountants’ attestation reports delivered by Wells Fargo Bank, NationalAssociation in the capacities described above are listed in the Exhibit Index.

Midland Loan Services, a Divisionof PNC Bank, National Association is the special servicer of the mortgage loansserviced under the Pooling and Servicing Agreement and the primary servicer ofthe Arizona Grand Resort & Spa Mortgage Loan. As a result, Midland LoanServices, a Division of PNC Bank, National Association is a “servicer” asdefined in Item 1108(a)(2)(iii) of Regulation AB, in the capacities describedabove, because it is servicing mortgage loans that constituted 10% or more ofthe assets of the issuing entity as of its cut-off date. The assessments ofcompliance with applicable servicing criteria, accountants’ attestation reportsand servicer compliance statements delivered by Midland Loan Services, aDivision of PNC Bank, National Association in the capacities described aboveare listed in the Exhibit Index.

Pentalpha Surveillance LLC is the operating advisor of themortgage loans serviced under the Pooling and Servicing Agreement and theArizona Grand Resort & Spa Mortgage Loan.  As a result, PentalphaSurveillance LLC is a servicing function participant in the capacitiesdescribed above, because it is servicing mortgage loans that constituted 5% ormore of the assets of the issuing entity as of its cut-off date. The assessmentsof compliance with applicable servicing criteria and accountants’ attestationreports delivered by Pentalpha Surveillance LLC in the capacities describedabove are listed in the Exhibit Index.

Wells Fargo Bank, NationalAssociation acts as trustee of the Arizona Grand Resort & Spa MortgageLoan.  Pursuant to the pooling and servicing agreement for the CSAIL2015-C3 Transaction, the trustee is required to provide an assessment ofcompliance with applicable servicing criteria solely with respect to Item1122(d)(2)(iii) of Regulation AB (regarding advances of funds or guaranteesregarding collections, cash flows or distributions, and any interest or otherfees charged for such advances, are made, reviewed and approved as specified inthe transaction agreements). However, during the reporting period, the trusteedid not perform any servicing function with respect to the servicing criteriaspecified in Item 1122(d)(2)(iii) of Regulation AB.  The master serviceror the special servicer, to the extent required, performed the servicingfunction identified with respect to Item 1122(d)(2)(iii) of Regulation AB, andeach such party included Item 1122(d)(2)(iii) of Regulation AB in theassessment of compliance with applicable servicing criteria and accountant’s attestationreport for the subject transaction.  As a result, this Annual Report onForm 10-K does not include an assessment of compliance with applicableservicing criteria of the trustee. One or more other servicers of the ArizonaGrand Resort & Spa Mortgage Loan have delivered one or more assessments ofcompliance with respect to Item 1122(d)(2)(iii) of Regulation AB.

Wilmington Trust, NationalAssociation acts as trustee of  the mortgage loans serviced under thePooling and Servicing Agreement.  Pursuant to the Pooling and ServicingAgreement, the trustee is required to provide an assessment of compliance withapplicable servicing criteria solely with respect to Item 1122(d)(2)(iii) ofRegulation AB (regarding advances of funds or guarantees regarding collections,cash flows or distributions, and any interest or other fees charged for suchadvances, are made, reviewed and approved as specified in the transactionagreements). However, during the reporting period, the trustee did not performany servicing function with respect to the servicing criteria specified in Item1122(d)(2)(iii) of Regulation AB.  The master servicer or the specialservicer, to the extent required, performed the servicing function identifiedwith respect to Item 1122(d)(2)(iii) of Regulation AB, and each such partyincluded Item 1122(d)(2)(iii) of Regulation AB in the assessment of compliancewith applicable servicing criteria and accountant’s attestation report for thesubject transaction.  As a result, this Annual Report on Form 10-K doesnot include an assessment of compliance with applicable servicing criteria ofthe trustee. One or more other servicers of  the mortgage loans servicedunder the Pooling and Servicing Agreement have delivered one or moreassessments of compliance with respect to Item 1122(d)(2)(iii) of RegulationAB.

This Annual Report on Form 10-Kincludes assessments of compliance with applicable servicing criteria andaccountants’ attestation reports from CoreLogic Solutions, LLC.  Thisentity was engaged by the master servicer under the Pooling and ServicingAgreement to remit tax payments received from the escrow accounts of borrowersto local taxing authorities, to report tax amounts due, to verify tax parcelinformation, and to verify non-escrow tax payments. These servicing functionsare included within the servicing criteria set forth in Items 1122(d)(4)(xi)and 1122(d)(4)(xii) of Regulation AB.  Therefore, under theprinciples-based definition of “servicer” set forth in Item 1101(j) ofRegulation AB that looks to the functions that an entity performs, this vendoris a “servicer” for the purposes of Item 1122 of Regulation AB.  *See*Compliance and Disclosure Interpretations, Section 301.01 (Item 1101(j)).

This Annual Report on Form 10-Kincludes an assessment of compliance with applicable servicing criteria,accountants’ attestation report and servicer compliance statement fromComputershare Trust Company, National Association (“CTCNA”).  CTCNAwas engaged by Wells Fargo Bank, National Association (“Wells Fargo”),in its capacity as certificate administrator and custodian, to perform certainspecified servicing functions identified in the assessment of compliance withapplicable servicing criteria and accountants’ attestation reports.  WellsFargo engaged CTCNA in connection with the sale of Wells Fargo’s corporatetrust services business to CTCNA and its affiliates.  Further, under theprinciples-based definition of “servicer” set forth in Item 1101(j) ofRegulation AB that looks to the functions that an entity performs, this partyis a “servicer” for the purposes of Item 1123 of Regulation AB.  SeeCompliance and Disclosure Interpretations, Section 301.01 (Item 1101(j)).

Theassessment of compliance with applicable servicing criteria, accountants’attestation report and servicer compliance statement of the certificateadministrator of the Arizona Grand Resort & Spa Mortgage Loan is omittedfrom this Annual Report on Form 10-K as the certificate administrator pursuantto the related pooling and servicing agreement or trust and servicing agreementdoes not perform any activities that address servicing criteria with respect tothe issuing entity and because it is not a “servicer” that meets the criteriain Item 1108(a)(2)(i) through (iii) of Regulation AB.

With respect to the *pari passu*loan combination that includes the Arizona Grand Resort & Spa MortgageLoan, (i) the report on assessment of compliance with servicing criteria andattestation report on assessment of compliance with servicing criteria ofRialto Capital Advisors, LLC as special servicer of the Arizona Grand Resort& Spa Mortgage Loan, listed on the Exhibit Index are omitted from thisAnnual Report on Form 10-K as they are not required to be included on thisAnnual Report on Form 10-K per Instruction 3 to Item 1122 of Regulation ABbecause it is a party performing activities that address servicing criteriarelating to 5% or less of the assets of the issuing entity; and (ii) theservicer compliance statement of Rialto Capital Advisors, LLC as special servicerof the Arizona Grand Resort & Spa Mortgage Loan, listed on the ExhibitIndex is omitted from this Annual Report on Form 10-K as it is not required byItem 1123 of Regulation AB to be included on this Annual Report on Form 10-Kbecause it is an unaffiliated party that is not a “servicer” that meets thecriteria in Item 1108(a)(2)(i) through (iii) of Regulation AB.

**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 ofFinancial Condition and Results of Operations.**

Omitted.

**Item 7A.  Quantitative and Qualitative DisclosuresAbout Market Risk.**

Omitted.

**Item 8.  Financial Statements and Supplementary Data.**

Omitted.

**Item 9.  Changes in and Disagreements WithAccountants 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 CorporateGovernance.**

Omitted.

**Item 11.  Executive Compensation.**

Omitted.

**Item 12.  Security Ownership of Certain BeneficialOwners and Management and Related Stockholder Matters.**

Omitted.

**Item 13.  Certain Relationships and RelatedTransactions, and Director Independence.**

Omitted.

**Item 14.  Principal Accounting Fees and Services.**

Omitted.

**ADDITIONAL DISCLOSURE ITEMS FOR REGULATION AB**

**Item 1112(b) of Regulation AB, Significant ObligorFinancial Information.**

The Fairmont Orchid Mortgage Loan(Loan # 1 on Annex A of the prospectus supplement of the registrant relating tothe issuing entity filed on November 25, 2015 pursuant to Rule 424(b)(5))constitutes a significant obligor within the meaning of Item 1101(k)(2) ofRegulation AB as disclosed in the prospectus supplement. In accordance withItem 1112(b) of Regulation AB, the most recent unaudited net operating incomeof the significant obligor was $12,002,496.56 for the twelve- month periodended December 31, 2021.

**Item 1114(b)(2) of Regulation AB, Significant EnhancementProvider Financial Information.**

No entity or group of affiliated entities provides any external creditenhancement or other support for the certificates within this transaction asdescribed under Item 1114(a) of Regulation AB.

**Item 1115(b) of Regulation AB, Certain DerivativesInstruments (Financial Information).**

No entity or group of affiliated entities provides anyderivative instruments or other support for the certificates within thistransaction as described under Item 1115 of Regulation AB.

**Item 1117 of Regulation AB, Legal Proceedings.**

The registrant knows of nomaterial pending legal proceeding involving the trust or any party related tothe trust, other than routine litigation incidental to the duties of thoserespective parties, and the following, with respect to Wells Fargo Bank,National Association, as trustee, as certificate administrator and ascustodian. 

In December 2014, Phoenix LightSF Limited and certain related entities and the National Credit UnionAdministration (NCUA) filed complaints in the United States District Court forthe Southern District of New York against Wells Fargo Bank, alleging claimsagainst Wells Fargo Bank in its capacity as trustee for a number of residentialmortgage-backed securities trusts. Complaints raising similar allegations havebeen filed by Commerzbank AG in the Southern District of New York and by IKBInternational and IKB Deutsche Industriebank in New York state court. In eachcase, the plaintiffs allege that Wells Fargo Bank, as trustee, caused losses toinvestors, and plaintiffs assert causes of action based upon, among otherthings, the trustee’s alleged failure to notify and enforce repurchaseobligations of mortgage loan sellers for purported breaches of representationsand warranties, notify investors of alleged events of default, and abide byappropriate standards of care following alleged events of default. Wells FargoBank previously settled two class action lawsuits with similar allegations thatwere filed in November 2014 and December 2016 by institutional investors in theSouthern District of New York and New York state court, respectively. Inaddition, Park Royal I LLC and Park Royal II LLC have filed complaints in NewYork state court alleging Wells Fargo Bank, N.A., as trustee, failed to takeappropriate actions upon learning of defective mortgage loan documentation. InMarch 2021, the Company entered into an agreement to resolve the case filed bythe NCUA.

 

In addition to the foregoingcases, in August 2014 and August 2015 Nomura Credit & Capital Inc. (“Nomura”)and Natixis Real Estate Holdings, LLC (“Natixis”) filed a total of seventhird-party complaints against Wells Fargo Bank in New York state court. In theunderlying first-party actions, Nomura and Natixis have been sued for allegedbreaches of representations and warranties made in connection with residentialmortgage-backed securities sponsored by them. In the third-party actions,Nomura and Natixis allege that Wells Fargo Bank, as master servicer, primaryservicer or securities administrator, failed to notify Nomura and Natixis oftheir own breaches, failed to properly oversee the primary servicers, andfailed to adhere to accepted servicing practices. Natixis additionally allegesthat Wells Fargo Bank failed to perform default oversight duties. Wells FargoBank has asserted counterclaims alleging that Nomura and Natixis failed toprovide Wells Fargo Bank notice of their representation and warranty breaches.

 

With respect to each of the foregoing litigations, Wells FargoBank believes plaintiffs' claims are without merit and intends to contest theclaims vigorously, but there can be no assurances as to the outcome of thelitigations or the possible impact of the litigations on Wells Fargo Bank orthe related RMBS trusts.

**Item 1119 of Regulation AB, Affiliations and CertainRelationships and Related Transactions.**

The information regarding this Item has been previouslyprovided in a prospectus supplement of the Registrant relating to the issuingentity filed on November 25, 2015 pursuant to Rule 424(b)(5).

**Item 1122 of Regulation AB, Compliance with ApplicableServicing Criteria.**

The reports on assessments of compliance with the servicingcriteria for asset-backed securities and related attestation reports on suchassessments of compliance with respect to the mortgage loans are attachedhereto under Item 15 to this Annual Report on Form 10-K. Attached as Exhibit Oto the Pooling and Servicing Agreement incorporated by reference as Exhibit 4.1to this Annual Report on Form 10-K is a chart identifying the entitiesparticipating in a servicing function for the transaction responsible for eachapplicable servicing criteria set forth in Item 1122(d).

The reports on assessments of compliance with the servicingcriteria for asset-backed securities and related attestation reports on suchassessments of compliance with respect to the Arizona Grand Resort & SpaMortgage Loan, which is being serviced and administered pursuant to the poolingand servicing agreement for the CSAIL 2015-C3 Transaction, are attached heretounder Item 15 to this Annual Report on Form 10-K. Attached as Exhibit O to thepooling and servicing agreement for the CSAIL 2015-C3 Transaction incorporatedby reference as Exhibit 4.2 to this Annual Report on Form 10-K is a chartidentifying the entities participating in a servicing function for the CSAIL2015-C3 Transaction responsible for each applicable servicing criteria setforth in Item 1122(d).

**Item 1123 of Regulation AB, Servicer Compliance Statement.**

The servicer compliance statements are attached as Exhibitsto this Annual Report on Form 10-K.

**PART IV**

**Item 15. Exhibits, Financial Statement Schedules**

(a) The following is a list of documents filed as part ofthis Annual Report on Form 10-K:

(1) Not applicable

(2) Not applicable

(3) See below

 

4.1          Pooling and Servicing Agreement, dated as of November 1,2015, by and among Credit Suisse First Boston Mortgage Securities Corp., asDepositor, Wells Fargo Bank, National Association, as Master Servicer, MidlandLoan Services, a Division of PNC Bank, National Association, as SpecialServicer, Pentalpha Surveillance LLC, as Operating Advisor, Wells Fargo Bank,National Association, as Certificate Administrator and Wilmington Trust,National Association, as Trustee (filed as Exhibit 4.1 to the registrant’sCurrent Report on Form 8-K filed on November 25, 2015 under Commission File No.333-206703-01 and incorporated by reference herein)

4.2          Pooling and Servicing Agreement, dated as of August 1,2015, by and among Credit Suisse First Boston Mortgage Securities Corp., asDepositor, Midland Loan Services, a Division of PNC Bank, National Association,as Master Servicer, Rialto Capital Advisors, LLC, as Special Servicer,Pentalpha Surveillance LLC, as Operating Advisor, Wells Fargo Bank, NationalAssociation, as Certificate Administrator and Wells Fargo Bank, NationalAssociation, as Trustee (filed as Exhibit 4.2 to the registrant’s CurrentReport on Form 8-K filed on November 25, 2015 under Commission File No.333-206703-01 and incorporated by reference herein)

4.3          Co-Lender Agreement, dated as of August 18, 2015, by andamong Column Financial, Inc., as Initial Note A-1 Holder and Column Financial,Inc., as Initial Note A-2 Holder (filed as Exhibit 4.3 to the registrant’sCurrent Report on Form 8-K filed on November 25, 2015 under Commission File No.333-206703-01 and incorporated by reference herein)

 

31           Rule 13a-14(d)/15d-14(d) Certifications.

33           Reports on assessment of compliance with servicing criteria for asset-backedsecurities.

33.1        Wells Fargo Bank, National Association, as MasterServicer

33.2        Midland Loan Services, a Division of PNC Bank,National Association, as Special Servicer

33.3        Wilmington Trust, National Association, as Trustee (Omitted. See ExplanatoryNotes.)

33.4        Wells Fargo Bank, National Association, asCertificate Administrator

33.5        Wells Fargo Bank, National Association, asCustodian

33.6        Pentalpha Surveillance LLC, as Operating Advisor

33.7        CoreLogic Solutions, LLC, as Servicing FunctionParticipant

33.8        Computershare Trust Company, National Association,as Servicing Function Participant for the Certificate Administrator on andafter November 1, 2021

33.9        Computershare Trust Company, National Association,as Servicing Function Participant for the Custodian on and after November 1,2021

33.10      Midland Loan Services, a Division of PNC Bank,National Association, as Primary Servicer of the Arizona Grand Resort & SpaMortgage Loan (see Exhibit 33.2)

33.11      Rialto Capital Advisors, LLC, as Special Servicer of the Arizona Grand Resort& Spa Mortgage Loan (Omitted. See Explanatory Notes.)

33.12      Wells Fargo Bank, National Association, as Trustee of the Arizona Grand Resort& Spa Mortgage Loan (Omitted. See Explanatory Notes.)

33.13      Wells Fargo Bank, National Association, asCustodian of the Arizona Grand Resort & Spa Mortgage Loan (see Exhibit33.5)

33.14      Pentalpha Surveillance LLC, as Operating Advisor ofthe Arizona Grand Resort & Spa Mortgage Loan (see Exhibit 33.6)

33.15      Computershare Trust Company, National Association,as Servicing Function Participant for the Custodian on and after November 1,2021 (see Exhibit 33.9)

34           Attestationreports on assessment of compliance with servicing criteria for asset-backedsecurities.

34.1        Wells Fargo Bank, National Association, as MasterServicer

34.2        Midland Loan Services, a Division of PNC Bank,National Association, as Special Servicer

34.3        Wilmington Trust, National Association, as Trustee (Omitted. See ExplanatoryNotes.)

34.4        Wells Fargo Bank, National Association, asCertificate Administrator

34.5        Wells Fargo Bank, National Association, asCustodian

34.6        Pentalpha Surveillance LLC, as Operating Advisor

34.7        CoreLogic Solutions, LLC, as Servicing FunctionParticipant

34.8        Computershare Trust Company, National Association,as Servicing Function Participant for the Certificate Administrator on andafter November 1, 2021

34.9        Computershare Trust Company, National Association,as Servicing Function Participant for the Custodian on and after November 1,2021

34.10      Midland Loan Services, a Division of PNC Bank,National Association, as Primary Servicer of the Arizona Grand Resort & SpaMortgage Loan (see Exhibit 34.2)

34.11      Rialto Capital Advisors, LLC, as Special Servicer of the Arizona Grand Resort& Spa Mortgage Loan (Omitted. See Explanatory Notes.)

34.12      Wells Fargo Bank, National Association, as Trustee of the Arizona Grand Resort& Spa Mortgage Loan (Omitted. See Explanatory Notes.)

34.13      Wells Fargo Bank, National Association, asCustodian of the Arizona Grand Resort & Spa Mortgage Loan (see Exhibit34.5)

34.14      Pentalpha Surveillance LLC, as Operating Advisor ofthe Arizona Grand Resort & Spa Mortgage Loan (see Exhibit 34.6)

34.15      Computershare Trust Company, National Association,as Servicing Function Participant for the Custodian on and after November 1,2021 (see Exhibit 34.9)

35           Servicer compliance statements.

35.1        Wells Fargo Bank, National Association, as MasterServicer

35.2        Midland Loan Services, a Division of PNC Bank,National Association, as Special Servicer

35.3        Wells Fargo Bank, National Association, asCertificate Administrator

35.4        Computershare Trust Company, National Association,as Servicing Function Participant for the Certificate Administrator on andafter November 1, 2021

35.5        Midland Loan Services, a Division of PNC Bank,National Association, as Primary Servicer of the Arizona Grand Resort & SpaMortgage Loan (see Exhibit 35.2)

35.6        Rialto Capital Advisors, LLC, as Special Servicer of the Arizona Grand Resort& Spa Mortgage Loan (Omitted. See Explanatory Notes.)

99.1         Mortgage Loan Purchase Agreement, dated as of November 1,2015, between Credit Suisse First Boston Mortgage Securities Corp. and ColumnFinancial, Inc. (filed as Exhibit 99.1 to the registrant’s Current Report onForm 8-K filed on November 25, 2015 under Commission File No. 333-206703-01 andincorporated by reference herein)

99.2         Mortgage Loan Purchase Agreement, dated as of November 1,2015, between Credit Suisse First Boston Mortgage Securities Corp. and BenefitStreet Partners CRE Finance LLC (filed as Exhibit 99.2 to the registrant’sCurrent Report on Form 8-K filed on November 25, 2015 under Commission File No.333-206703-01 and incorporated by reference herein)

99.3         Mortgage Loan Purchase Agreement, dated as of November 1,2015, among Credit Suisse First Boston Mortgage Securities Corp., Walker &Dunlop Commercial Property Funding I CS, LLC and Walker & Dunlop CommercialProperty Funding, LLC (filed as Exhibit 99.3 to the registrant’s Current Reporton Form 8-K filed on November 25, 2015 under Commission File No. 333-206703-01and incorporated by reference herein)

99.4         Mortgage Loan Purchase Agreement, dated as of November 1,2015, between Credit Suisse First Boston Mortgage Securities Corp. and The BancorpBank (filed as Exhibit 99.4 to the registrant’s Current Report on Form 8-Kfiled on November 25, 2015 under Commission File No. 333-206703-01 andincorporated by reference herein)

99.5         Mortgage Loan Purchase Agreement, dated as of November 1,2015, between Credit Suisse First Boston Mortgage Securities Corp. and MC-FiveMile Commercial Mortgage Finance LLC (filed as Exhibit 99.5 to the registrant’sCurrent Report on Form 8-K filed on November 25, 2015 under Commission File No.333-206703-01 and incorporated by reference herein)

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

(c)    Not Applicable.

 

**SIGNATURES**

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

Credit Suisse First Boston MortgageSecurities Corp.(Depositor)

/s/ Oliver Nisenson

Oliver Nisenson, Director

(senior officer in charge ofsecuritization of the depositor)

Date: March 16, 2022