Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Nolan Mangini Siobhan
   2. Issuer Name and Ticker or Trading Symbol
CASTLIGHT HEALTH, INC. [CSLT] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CFO & Treasurer
(Last)
(First)
(Middle)
C/O CASTLIGHT HEALTH, INC., 150 SPEAR ST., SUITE 400		 3. Date of Earliest Transaction (Month/Day/Year)
05/15/2017
(Street)

SAN FRANCISCO, CA 94105		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Class B Common Stock 05/15/2017   M(1)   625 A $ 0 33,774 D  
Class B Common Stock 05/15/2017   M(2)   1,875 A $ 0 35,649 D  
Class B Common Stock 05/16/2017   S   1,009 (3) D $ 3.9651 (4) 34,640 D  
Class B Common Stock 05/16/2017   M(5)   2,500 A $ 0 37,140 D  
Class B Common Stock 05/16/2017   M(6)   1,875 A $ 0 39,015 D  
Class B Common Stock 05/17/2017   S   1,756 (3) D $ 3.6558 (7) 37,259 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Restricted Stock Units $ 0 (8) 05/15/2017   M(1)     625   (9)   (9) Class B common stock 625 $ 0 4,375 D  
Restricted Stock Units $ 0 (8) 05/15/2017   M(2)     1,875   (10)   (10) Class B Common Stock 1,875 $ 0 16,875 D  
Restricted Stock Units $ 0 (8) 05/16/2017   M(5)     2,500   (11)   (11) Class B Common Stock 2,500 $ 0 25,000 D  
Restricted Stock Units $ 0 (8) 05/16/2017   M(6)     1,875   (12)   (12) Class B Common Stock 1,875 $ 0 20,625 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Nolan Mangini Siobhan
C/O CASTLIGHT HEALTH, INC.
150 SPEAR ST., SUITE 400
SAN FRANCISCO, CA 94105		       CFO & Treasurer  

Signatures

 /s/ Jennifer Chaloemtiarana, by power of attorney   05/17/2017
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Release and settlement of restricted stock units ("RSUs") granted to the Reporting Person on May 15, 2015, the grant of which was previously reported by the Reporting Person on a Form 3.
(2) Release and settlement of RSUs granted to the Reporting Person on August 17, 2015, the grant of which was previously reported by the Reporting Person on a Form 3.
(3) Represents the aggregate number of shares sold by the Reporting Person on the same day at different prices. All of these shares were sold to cover taxes and fees due upon the release and settlement of the RSU's. The Reporting Person did not sell or otherwise dispose of any of the shares reported on this Form 4 for any reason other than to cover required taxes and fees.
(4) Represents the weighted average sales price per share. The shares sold at prices ranging from $3.85 to $4.10 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer.
(5) Release and settlement of RSUs granted to the Reporting Person on November 16, 2015, the grant of which was previously reported by the Reporting Person on a Form 3.
(6) Release and settlement of RSUs granted to the Reporting Person on February 26, 2016, the grant of which was previously reported by the Reporting Person on a Form 3.
(7) Represents the weighted average sales price per share. The shares sold at prices ranging from $3.4759 to $3.85 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer
(8) Each RSU represents a contingent right to receive 1 share of the Issuer's Class B common stock upon settlement for no consideration.
(9) 25% of the RSUs vested on February 15, 2016 and the remainder will vest quarterly over three years thereafter in equal installments. Shares of the Issuer's Class B common stock will be delivered to the Reporting Person following vesting, at which time shares will be sold by the Reporting Person to cover any tax withholding obligations.
(10) 25% of the RSUs will vest on August 15, 2016 and the remainder will vest quarterly over three years thereafter in equal installments. Shares of the Issuer's Class B common stock will be delivered to the Reporting Person following vesting, at which time shares will be sold by the Reporting Person to cover any tax withholding obligations.
(11) 25% of the RSUs vested on November 16, 2016 and the remainder vest quarterly over three years thereafter in equal installments. Shares of the Issuer's Class B common stock will be delivered to the Reporting Person following vesting, at which time shares will be sold by the Reporting Person to cover any tax withholding obligations.
(12) 25% of the RSUs vested on February 16, 2017 and the remainder will vest quarterly over three years thereafter in equal installments. Shares of the Issuer's Class B common stock will be delivered to the Reporting Person following vesting, at which time shares will be sold by the Reporting Person to cover any tax withholding obligations.

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