Filing Details

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

o

Rule 13d-1(b)

o

Rule 13d-1(c)

x

Rule 13d-1(d)

1.

Names of Reporting Persons
SIG China Investments Master Fund III, LLLP

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
423,875,937

6.

Shared Voting Power *
423,875,937

7.

Sole Dispositive Power
423,875,937

8.

Shared Dispositive Power *
423,875,937

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
423,875,937

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
14.4%

12.

Type of Reporting Person (See Instructions)
PN

1.

Names of Reporting Persons
SIG Asia Investment, LLLP

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power *
423,875,937

7.

Sole Dispositive Power
0

8.

Shared Dispositive Power *
423,875,937

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
423,875,937

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
14.4%

12.

Type of Reporting Person (See Instructions)
PN

1.

Names of Reporting Persons
Heights Capital Management, Inc.

2.

Check the Appropriate Box if a Member of a Group (See Instructions)

(a)

o

(b)

o

3.

SEC Use Only

4.

Citizenship or Place of Organization
Delaware

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
0

6.

Shared Voting Power *
423,875,937

7.

Sole Dispositive Power
0

8.

Shared Dispositive Power *
423,875,937

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
423,875,937

10.

Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)  o

11.

Percent of Class Represented by Amount in Row (9)
14.4%

12.

Type of Reporting Person (See Instructions)
CO

Item 1.

(a)

Name of Issuer
CooTek (Cayman) Inc. (the Company)

(b)

Address of Issuers Principal Executive Offices

Building 7

No. 2007 Hongmei Road

Xuhui District

Shanghai, 201103

Peoples Republic of China

Item 2.

(a)

Name of Person Filing

This statement is filed by the entities listed below, who are collectively referred to herein as Reporting Persons with respect to the Class A Ordinary Shares, par value US$0.00001 per share (the Shares).

(i) SIG China Investments Master Fund III, LLLP

(ii) SIG Asia Investment, LLLP

(iii) Heights Capital Management, Inc.

(b)

Address of Principal Business Office or, if none, Residence

The address of the principal business office of each of SIG China Investments Master Fund III, LLLP and SIG Asia Investment, LLLP is:

One Commerce Center

1201 N. Orange Street, Suite 715

Wilmington DE 19801

The address of the principal business office of Heights Capital Management, Inc. is:

101 California Street, Suite 3250

San Francisco, California 94111

(c)

Citizenship
Citizenship is set forth in Row 4 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.

(d)

Title of Class of Securities
Class A Ordinary Shares, par value US$0.00001 per share

(e)

CUSIP Number
There is no CUSIP assigned to the Class A Ordinary Shares.  CUSIP number 21718L102 has been assigned to the American Depositary Receipts (ADRs) of the Company, which are quoted on the New York Stock Exchange under the symbol CTK.  Each ADR represents 50 Class A Ordinary Shares.

Item 3.

If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

o

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b)

o

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

o

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

o

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

o

An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);

(f)

o

An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);

(g)

o

A parent holding company or control person in accordance with §240.13d-1(b)(1)(ii)(G);

(h)

o

A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

o

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

o

A non-U.S. institution in accordance with § 240.13d1(b)(1)(ii)(J);

(k)

o

Group, in accordance with § 240.13d1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with

§ 240.13d1(b)(1)(ii)(J), please specify the type of institution:____________________________

Item 4.

Ownership

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

The information required by Items 4(a) - (c) is set forth in Rows 5 - 11 of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.

The Companys Prospectus, filed on September 28, 2018 (Registration No. 333-226867), indicates there were 2,949,607,236 Shares outstanding as of the completion of the offering of American Depositary Shares referred to therein. 

SIG Asia Investment, LLLP, which serves as the investment manager to SIG China Investments Master Fund III, LLLP, may be deemed to be the beneficial owner of all Shares owned by SIG China Investments Master Fund III, LLLP.  Heights Capital Management, Inc., which serves as the investment manager to SIG Asia Investment, LLLP, may be deemed to be the beneficial owner of all Shares owned by SIG China Investments Master Fund III. Each of the Reporting Persons hereby disclaims any beneficial ownership of any such Shares, except for their pecuniary interest therein.

Item 5.

Ownership of Five Percent or Less of a Class

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following   o

Item 6.

Ownership of More than Five Percent on Behalf of Another Person

Not Applicable

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person

Not Applicable

Item 8.

Identification and Classification of Members of the Group

Not Applicable

Item 9.

Notice of Dissolution of Group

Not Applicable

Item 10.

Certification

Not Applicable

Dated: February 12, 2019

SIG China Investments Master Fund III, LLLP

By:

SIG Asia Investment, LLLP,

pursuant to a Limited Power of Attorney, a copy of which is attached as Exhibit I hereto

By:

Heights Capital Management, Inc.,

Pursuant to a Limited Power of Attorney, a copy of which is attached as Exhibit II hereto

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel

SIG Asia Investment, LLLP

By:

Heights Capital Management, Inc.,

Pursuant to a Limited Power of Attorney, a copy of which is attached as Exhibit II hereto

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel

Heights Capital Management, Inc.

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel

Exhibit

Description

I

Limited Power of Attorney for SIG China Investments Master Fund III, LLLP

II

Limited Power of Attorney for SIG Asia Investment, LLLP

III

Joint Filing Agreement

THE COMMON SEAL OF SIG CHINA INVESTMENTS MASTER FUND III, LLLP

SIG China Investments Master Fund III, LLLP

By:

SIG China Investments GP, LLC

its general partner

By:

/s/ Brian Sullivan

Brian Sullivan, Treasurer

SIG ASIA INVESTMENT, LLLP

By:

/s/ Brian Sullivan

Brian Sullivan, Treasurer

SIG China Investments Master Fund III, LLLP

By:

SIG Asia Investment, LLLP,

pursuant to a Limited Power of Attorney

By:

Heights Capital Management Inc.,

pursuant to a Limited Power of Attorney

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel

SIG Asia Investment, LLLP

By:

Heights Capital Management Inc.,

pursuant to a Limited Power of Attorney

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel

Heights Capital Management, Inc.

By:

/s/ Michael Spolan

Name:

Michael Spolan

Title:

General Counsel