UNITED STATES	
SECURITIES AND EXCHANGE COMMISSION	
Washington, D.C. 20549	
 	
SCHEDULE 13G	
 	
Under the Securities Exchange Act of 1934	
 	
(Amendment No.  )*	
 	
Castlight Health, Inc.	
(Name of Issuer)	
 	
Class B Common Stock, par value $0.0001 per share	
(Title of Class of Securities)	
 	
14862Q100	
(CUSIP Number)	
 	
February 8, 2019	
(Date of Event Which Requires Filing of this Statement)	
 
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:	
 	
o	Rule 13d-1(b)	
x	Rule 13d-1(c)	
o	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).  

 	

CUSIP No. 14862Q100	13G	Page 2 of 6	

1.	Names Of Reporting Person
I.R.S. Identification No. Of Above Person (Entities Only)
 
Neil Gagnon

2.	check the appropriate box if a group	(a) o
( b) x	
	
3.	sec use only	 	 	
 	 	 	 	
4.	citizenship or place of organization
 
USA
 	 	 	
number of
shares
beneficially
owned by
each
reporting
person with:	5.	sole voting power	 	 	433,050	
	6.	shared voting power	 	 	4,679,825	
	7.	sole dispositive power	 	 	433,050	
	8.	shared dispositive power	 	 	4,752,726	
9.	aggregate amount beneficially owned by each reporting person	 	5,185,776	
10.	check box if the aggregate amount in row (9) excludes certain shares (See Instructions)	o	
11.	percent of class represented by amount in row (9)	 	5.1%	
12.	type of reporting person (See Instructions)	   	IN	

 	

CUSIP No. 14862Q100	13G	Page 3 of 6	
Item 1.	 	
 
(a)	Name of Issuer:	Castlight Health, Inc.	
 	 	 	
(b)	Address of Issuer’s Principal
Executive Offices:	150 Spear Street, Suite 400
San Francisco, CA 94105	

Item 2.  

(a)	Name of Person Filing:	
Neil Gagnon has sole voting and dispositive power over 433,050 shares of the Issuer’s Class B Common Stock, par value $0.0001 per share (the “common stock”). In addition, Mr. Gagnon has shared voting power over 4,679,825 shares of common stock and shared dispositive power over 4,752,726 shares of common stock.
 
Mr. Gagnon is the managing member and principal owner of Gagnon Securities LLC (“GS”), an investment adviser registered with the U.S. Securities and Exchange Commission (“SEC”) under the Investment Advisers Act of 1940, as amended (the “Advisers Act”), and a registered broker-dealer, in its role as investment manager to several customer accounts, foundations, partnerships and trusts (collectively, the “Accounts”) to which it furnishes investment advice. GS and Mr. Gagnon may be deemed to share voting power with respect to 2,855,746 shares of common stock held in the Accounts and dispositive power with respect to 2,911,904 shares of common stock held in the Accounts. GS and Mr. Gagnon expressly disclaim beneficial ownership of all securities held in the Accounts.
 
Mr. Gagnon is also the Chief Executive Officer of Gagnon Advisors, LLC (“Gagnon Advisors”), an investment adviser registered with the SEC under the Advisers Act. Mr. Gagnon and Gagnon Advisors, in its role as investment manager to Gagnon Investment Associates, LLC (“GIA”), a private investment fund, may be deemed to share voting and dispositive power with respect to the 2,122,194 shares of common stock held by GIA. Gagnon Advisors and Mr. Gagnon expressly disclaim beneficial ownership of all securities held by GIA.

(b)	Address of Principal Business Office 
or, if none, Residence:	1370 Ave. of the Americas, 24 th Floor 
New York, NY 10019	

(c)	Citizenship:	USA	
 	 	 	
(d)	Title of Class of Securities:	Class B Common Stock, par value $0.0001 per share	
 	 	 	
(e)	CUSIP Number:	14862Q100	

 	

 	

CUSIP No. 14862Q100	13G	Page 4 of 6	
 
Item 3.	If this statement is filed pursuant to §§240.13d-1(b) or 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 § 13d-1(b)(1)(ii)(G);	
 	 	 	
(h)	  o	A savings associations 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 (15U.S.C. 80a-3);	
 	 	 	
(j)	  o	A non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J);	
 	 	 	
(k)	  o	Group, in accordance with §240.13d-1(b)(1)(ii)(K). If filing as a non-U.S. institution in accordance with §240.13d-1(b)(1)(ii)(J), please specify the type of institution: _____	

 	

CUSIP No. 14862Q100	13G	Page 5 of 6	
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:	5,185,776	
 	 	 	 	
 	(b)	Percent of class:	5.1%	
 	 	 	 	
 	 	 	Calculation of percentage of beneficial ownership is based on 101,652,931 shares of the Issuer’s common stock outstanding as of November 5, 2018, as reported on the Issuer’s Form 10-Q filed on November 7, 2018.	
 	 	 	 	
 	(c)	Number of shares as to which the person has:	
 
 	Sole power to vote or to direct the vote:	433,050	
 	 	 	
 	Shared power to vote or to direct the vote:	4,679,825	
 	 	 	
 	Sole power to dispose or to direct the disposition of:	433,050	
 	 	 	 	
 	Shared power to dispose or to direct the disposition of:	4,752,726	
 
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 Accounts described above in Item 2 have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, securities held in their respective accounts. To the knowledge of the Reporting Person, the interest in any such account does not exceed 5% of the class of securities. Except to the extent described herein, the Reporting Person disclaims beneficial ownership of all such securities.

Items 7 – 9.	Not Applicable.	

 	

CUSIP No. 14862Q100	13G	Page 6 of 6	
 	 	
Item 10.	Certification.	
 
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under Section 230.14a-11.

SIGNATURE
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 14, 2019
 	 	
 	NEIL GAGNON	
 	 	
 	/s/ Neil Gagnon