UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
 
SCHEDULE 13G
(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED
PURSUANT TO RULE 13d-2(b)
(Amendment No. ___)*
 
 
Entegris, Inc.
(Name of Issuer)
 
 
Common Stock, $.01 par value per share
(Title of Class of Securities)
     
     
 
29362U104
  
(CUSIP Number)
 
 
 December 31, 2009
(Date of Event which Requires Filing of this Statement)
 
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

    x
Rule 13d-1(b)
     
 
  o
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 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. 29362U104
 
13G
 Page 2 of 5 Pages
 
1
NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
 
Chilton Investment Company, LLC
87-0742367
  
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
 
 
(a)
o
 
(b)
x
3
SEC USE ONLY
 
 
  
4
CITIZENSHIP OR PLACE OF ORGANIZATION
 
State of Delaware
  
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH
5.
SOLE VOTING POWER
7,401,055
 
6.
SHARED VOTING POWER
0
 
7.
SOLE DISPOSITIVE POWER
7,401,055
 
8.
SHARED DISPOSITIVE POWER
0
 
9.
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
7,401,055
 
10.
CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (See Instructions)
 
11.
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.7%
 
12.
TYPE OF REPORTING PERSON (See Instructions)
IA
 
 
 
CUSIP No. 29362U104
 
13G
 Page 3 of 5 Pages
 

Item 1(a).
Name of Issuer.
Entegris, Inc.
 
Item 1(b).
 
Address of Issuer’s Principal Executive Offices.
129 Concord Road, Billerica, MA 01821
 
Item 2(a).
 
Names of Person Filing.
Chilton Investment Company, LLC
 
Item 2(b).
 
Address of Principal Business Office or, if None, Residence.
1266 East Main Street, 7th Floor
Stamford, CT 06902
 
Item 2(c).
 
Citizenship.
State of Delaware
Item 2(d).
 
Title of Class of Securities.
Common Stock, $.01 par value
 
Item 2(e).
 
CUSIP Number.
29362U104

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)
 o
Broker or dealer registered under Section 15 of the Exchange Act.
 
(b)
o
Bank as defined in Section 3(a)(6) of the Exchange Act.
 
(c)
 o
Insurance company as defined in Section 3(a)(19) of the Exchange Act.
 
(d)
 o
Investment company registered under Section 8 of the Investment Company Act.
 
(e)
 x
An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
 
(f)
 o
An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
 
(g)
 o
A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);
 
(h)
 o
A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;
 
(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;
 
(j)
 o
 Group, in accordance with Rule 13d-1(b)(1)(ii)(J).
 
 
CUSIP No. 29362U104
 
13G
 Page 4 of 5 Pages

 
Item 4.
Ownership.
     
   
(a)      Amount beneficially owned: 7,401,055 shares
     
   
(b)      Percent of class:  5.7%
     
   
(c)      Number of shares as to which the person has:

 
(i)
(ii)
(iii)
(iv)
Sole power to vote or to direct the vote:  7,401,055
Shared power to vote or to direct the vote:  0
Sole power to dispose or to direct the disposition of:  7,401,055
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.
     
   
Inapplicable.
     
 
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
     
   
Inapplicable.
     
 
Item 8.
Identification and Classification of Members of the Group.
     
   
Inapplicable.
     
 
Item 9.
Notice of Dissolution of Group.
     
   
Inapplicable.
 
 
CUSIP No. 29362U104
 
13G
 Page 5 of 5 Pages
 

Item 10.
Certifications.

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.

 
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.
 
Date:  February 12, 2010
 
Chilton Investment Company, LLC
  
       
       
By:
/s/ James Steinthal
  
  Name:
James Steinthal
  
  Title:
Executive Vice President