Filing Details

x

Rule 13d-1(b)

o

Rule 13d-1(c)

o

Rule 13d-1(d)

CUSIP No. 229050307

1.

Names of Reporting Persons
Alger Associates, Inc. 13-3017981

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
New York

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
3,184,080

6.

Shared Voting Power
0

7.

Sole Dispositive Power
3,184,080

8.

Shared Dispositive Power
0

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
3,184,080

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)
5.55%

12.

Type of Reporting Person (See Instructions)
HC

CUSIP No. 229050307

1.

Names of Reporting Persons
Fred Alger & Company, Incorporated 13-2665689

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
3,184,080

6.

Shared Voting Power
0

7.

Sole Dispositive Power
3,184,080

8.

Shared Dispositive Power
0

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
3,184,080

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)
5.55%

12.

Type of Reporting Person (See Instructions)
BD

CUSIP No. 229050307

1.

Names of Reporting Persons
Fred Alger 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
New York

Number of
Shares
Beneficially
Owned by
Each
Reporting
Person With

5.

Sole Voting Power
3,184,080

6.

Shared Voting Power
0

7.

Sole Dispositive Power
3,184,080

8.

Shared Dispositive Power
0

9.

Aggregate Amount Beneficially Owned by Each Reporting Person
3,184,080

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)
5.55%

12.

Type of Reporting Person (See Instructions)
IA

Item 1.

(a)

Name of Issuer
Tandem Diabetes Care Inc.

(b)

Address of Issuers Principal Executive Offices
11045 Roselle Street, San Diego, CA 92121

Item 2.

(a)

Name of Person Filing
Alger Associates, Inc.

Fred Alger & Company, Incorporated

Fred Alger Management, Inc.

(b)

Address of Principal Business Office or, if none, Residence
360 Park Avenue South, New York, NY 10010

(c)

Citizenship
Alger Associates, Inc. New York

Fred Alger & Company, Incorporated Delaware

Fred Alger Management, Inc. New York

(d)

Title of Class of Securities
Common Stock

(e)

CUSIP Number
875372203

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)

x

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.

(a)

Amount beneficially owned:   

3,184,080

(b)

Percent of class:   

5.55%

(c)

Number of shares as to which the person has:

(i)

Sole power to vote or to direct the vote   

3,184,080

(ii)

Shared power to vote or to direct the vote    

0

(iii)

Sole power to dispose or to direct the disposition of   

3,184,080

(iv)

Shared power to dispose or to direct the disposition of   

0

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

The securities reported herein are beneficially owned by one or more open-end investment companies or other managed accounts that are investment management clients of Fred Alger Management, Inc., (FAM) a registered investment adviser. FAM is a 100% owned subsidiary of Fred Alger & Company, Incorporated (FAC) a registered broker dealer. FAC is a 100% owned subsidiary of Alger Associates, Inc., a holding company.

Item 7.

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

See Exhibit A

Item 8.

Identification and Classification of Members of the Group

Item 9.

Notice of Dissolution of Group

Item 10.

Certification

By: Alger Associates, Inc.

By:

/s/ Hal Liebes

Name: Hal Liebes

Title: Director

Date: February 8, 2019

By: Fred Alger & Company, Incorporated

By:

/s/ Tina Payne

Name: Tina Payne

Title: Senior Vice President

Date: February 8, 2019

By: Fred Alger Management, Inc.

By:

/s/ Tina Payne

Name: Tina Payne

Title: Senior Vice President

Date: February 8, 2019

By: Alger Associates, Inc.

By:

/s/ Hal Liebes

Name: Hal Liebes

Title: Director

Date: February 8, 2019

By: Fred Alger & Company, Incorporated

By:

/s/ Tina Payne

Name: Tina Payne

Title: Senior Vice President

Date: February 8, 2019

By: Fred Alger Management, Inc.

By:

/s/ Tina Payne

Name: Tina Payne

Title: Senior Vice President

Date: February 8, 2019