CUSIP No. 14862Q100	 	13G	 	Page 1 of 5 Pages	

 
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G
INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULE 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO
RULE 13d-2
(Amendment No. 1)*

Castlight Health, Inc.
(Name of Issuer)
Class B Common Stock, $0.0001 par value per share
(Title of Class of Securities)
14862Q100
(CUSIP Number)
31 December 2018
(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
 
 	☐	Rule 13d-1(b)	
 
 	☐	Rule 13d-1(c)	
 
 	☒	Rule 13d-1(d)	
 
*	The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.	
The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

 
 
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CUSIP No. 14862Q100	 	13G	 	Page 2 of 5 Pages	

  1 	 	NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
 
The Wellcome Trust Limited as trustee of the Wellcome Trust	
  2	 	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
(a)  ☐        (b)  ☐
 	
  3	 	SEC USE ONLY
 	
  4	 	CITIZENSHIP OR PLACE OF ORGANIZATION
 
United Kingdom	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH	  	    5    	  	 SOLE VOTING POWER
 
 6,650,096 (1)	
	  	    6    	  	 SHARED VOTING POWER
 	
	  	    7    	  	 SOLE DISPOSITIVE POWER
 
 6,650,096 (1)	
	  	    8    	  	 SHARED DISPOSITIVE POWER
 	
  9	 	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 
6,650,096 (1)	
10	 	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ☐
 	
11	 	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
 
6.14% (2)	
12	 	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
 
OO	
 
(1)  	The reporting person is reporting the beneficial ownership of 6,650,096 shares of the Issuer’s Class B Common Stock on this Schedule 13G as a result of the reporting person’s direct ownership of 6,650,096 shares of the Issuer’s Class A Common Stock, which shares of Class A Common Stock may be converted into the Issuer’s Class B Common Stock at an exchange rate of one to one upon the election of the reporting person.	
(2)  	In calculating the percentage of the Issuer’s Class B Common Stock beneficially owned by the reporting person for purposes of this Schedule 13G, both the numerator and denominator assume full conversion of the Class A Common Stock held by the reporting person into Class B Common Stock.	
 
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CUSIP No. 14862Q100	 	13G	 	Page 3 of 5 Pages	
 
Schedule 13G

		
Item 1(a).	 	Name of Issuer: Castlight Health, Inc.	
		
Item 1(b).	 	Address of Issuer’s Principal Executive Offices : 121 Spear Street, Suite 300, San Francisco, California 94105	
		
Item 2(a).	 	Name of Persons Filing : The Wellcome Trust Limited as trustee of the Wellcome Trust	
		
Item 2(b).	 	Address of Principal Business Office or, if None, Residence : 215 Euston Road, London NW1 2BE, United Kingdom	
		
Item 2(c).	 	Citizenship : United Kingdom	
		
Item 2(d).	 	Title of Class of Securities : Class B Common Stock, $0.0001 par value per share	
		
Item 2(e).	 	CUSIP Number : 14862Q100	
		
Item 3.	 	If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a :	
			
(a)	 	[    ]	 	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).	
			
(b)	 	[    ]	 	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).	
			
(c)	 	[    ]	 	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).	
			
(d)	 	[    ]	 	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C 80a-8).	
			
(e)	 	[    ]	 	An investment adviser in accordance with §240.13d-1(b)(1)(ii)(E);	
			
(f)	 	[    ]	 	An employee benefit plan or endowment fund in accordance with §240.13d-1(b)(1)(ii)(F);	
			
(g)	 	[    ]	 	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);	
			
(h)	 	[    ]	 	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);	
			
(i)	 	[    ]	 	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)	 	[    ]	 	Group, in accordance with §240.13d-1(b)(1)(ii)(J).	
 
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CUSIP No. 14862Q100	 	13G	 	Page 4 of 5 Pages	

		
Item 4.	  	Ownership .	
		
	  	The information in items 1 and 5 through 11 on the cover page (p. 2) of this Schedule 13G is hereby incorporated by reference.	
		
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 5 percent of the class of securities, check the following [    ].	
		
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.	
 
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CUSIP No. 14862Q100	 	13G	 	Page 5 of 5 Pages	
 
SIGNATURES
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 6, 2019	 		 	The Wellcome Trust Limited
as trustee of the Wellcome Trust	
			
	 		 	/s/ Nick Moakes	
	 		 	Name:	 	Nick Moakes	
	 		 	Title:	 	Chief Investment Officer	
 
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