UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
				(Amendment No. _1__)

hi/fn, inc.
                  _____________________________________________
         (Name of Issuer)

Common Stock
                  _______________________________________________
(Title of Class of Securities)

428358105
                 _________________________________________________
(CUSIP Number)


		with a copy to:
Austin W. Marxe		Allen B. Levithan, Esq.
527 Madison Avenue, Suite 2600		Lowenstein Sandler PC
New York, New York 10022		65 Livingston Avenue
			Roseland, New Jersey  07068
			(973) 597-2406
(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

December 31, 2005
(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)
	_x__	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
disclosures provided in a prior cover page.
The information required on 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. 428358105       13G                           Page 2 of 6 Pages
1.Names of Reporting Persons.  I.R.S. Identification Nos. of above persons
(entities only):

	Austin W. Marxe and David M. Greenhouse

2.	Check the Appropriate Box if a Member of a Group (See Instructions):
	(a)	[    ]	 	Not Applicable
	(b)	[    ]

	3.	SEC Use Only

	4.	Source of Funds (See Instructions):  00

	5.	Check if Disclosure of Legal Proceedings Is Required Pursuant to
Items 2(d) or 2(e):
				Not Applicable

	6.	Citizenship or Place of Organization:	    United States

	Number of	7.	Sole Voting Power:	0
	Shares Beneficially	8.	Shared Voting Power:	1,584,489*
	Owned by
	Each Reporting	9.	Sole Dispositive Power:	0
	Person With	10.	Shared Dispositive Power:1,584,489*____

	11.	Aggregate Amount Beneficially Owned by Each Reporting Person:
         1,584,489*

	12.	Check if the Aggregate Amount in Row (11) Excludes Certain Shares
		(See Instructions):		               Not Applicable

	13.	Percent of Class Represented by Amount in Row (11):     11.6%*

	14.	Type of Reporting Person (See Instructions):       IA, IN


* This is a joint filing by Austin W. Marxe (?Marxe?) and David M. Greenhouse
(?Greenhouse?).  Marxe and Greenhouse share sole voting and investment power
over 125,688 shares of Common Stock owned by Special Situations Cayman Fund,
L.P., 464,577 shares of Common Stock owned by Special Situations Fund III QP,
L.P., 40,724 shares of Common Stock owned by Special Situations Fund III,
L.P., 93,300 shares of Common Stock owned by Special Situations Technology
Fund, L.P. and 860,200 shares of Common Stock owned by Special Situations
Technology Fund II, L.P.  See Items 2 and 4 of this Schedule for additional
information.


								Page 3 of 6 Pages
Item 1.	Security and Issuer:
	(a) hi/fn, inc.
	(b) 750 University Avenue, Los Gatos, CA 95032

Item 2. (a)	Name of Person Filing:
	The persons filing this report are Austin W. Marxe (?Marxe?) and
David M. Greenhouse (?Greenhouse?), who are the controlling principals of AWM
Investment Company, Inc. (?AWM?), the general partner of and investment
adviser to Special Situations Cayman Fund, L.P. (?Cayman?).  AWM also serves
as the general partner of MGP Advisers Limited Partnership (?MGP?), the
general partner of and investment adviser to Special Situations Fund III, L.P.
(?SSF3?) and Special Situations Fund III QP, L.P.* (?SSFQP?).  Marxe and
Greenhouse are also members of SST Advisers, L.L.C. (?SSTA?), the general
partner of and investment adviser to Special Situations Technology Fund, L.P.
(?Technology?) and Special Situations Technology Fund II, L.P. (?Technology
II?).   (SSF3, SSFQP, Cayman, Technology and Technology II will hereafter be
referred to as, the ?Funds?).  The principal business of each Fund is to
invest in equity and equity-related securities and other securities of any
kind or nature.

*	* Pursuant to that certain Exchange Tender Offer described in the
Schedule TO-I of the Special Situations Fund III, L.P. (SSF3) as filed
by SSF3 with the Securities and Exchange Commission on November 17,
2005, SSF3 transferred the securities included in this Schedule 13G to
Special Situations Fund III QP, L.P. (SSFQP) on December 31, 2005.


             (b) Address of Principal Business Office or, if none, Residence:

	The principal business address for Marxe and Greenhouse is 527
Madison Avenue, Suite 2600, New York, NY  10022.


              (c) Citizenship:

       	           Austin W. Marxe and David M. Greenhouse are United
States citizens.

              (d) Title of Class of Securities:  Common Stock
	              (e) CUSIP Number:  428358105.

Item 3.     If this statement is filed pursuant to $240.13d-1(b) or 240.13d-
2(b), check whether
                the person filing is a:    Not Applicable

(a) ( )	Broker or Dealer registered under section 15 of the Act;
(b) ( )	Bank as defined in section 3(a) (6) of the Act;
(c) ( )	Insurance Company as defined in section 3(a) (19) of the Act;
(d) ( )	Investment Company registered under section 8 of the Investment
Company Act of 1940;
(e) ( )	An Investment Adviser in accordance with $240.13d
		-1(b)(I)(ii)(E);
(f) ( )	An employee benefit plan or endowment fund in accordance with
$240.13d-1(b)(I)(ii)(F);


								Page 4 of 6 Pages

(g) ( )	A parent holding company or control person in accordance with
$240.13d-
	1(b)(1)(ii)(G);
(h) ( ) 	A savings association as defined in Section 3(b) of the Federal
Deposit Insurance

	Act;
(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;
(j) ( )   		Group, in accordance with $240.13d-1(b)(1)(ii)(J).


Item 4.       Ownership:

	 (a) Amount Beneficially Owned:  Messrs. Marxe and Greenhouse
beneficially own a total of 1,584,489 shares of Common Stock. This amount
includes 125,688 shares of Common Stock owned by Cayman, 93,300 shares of
Common Stock owned by Technology, 860,200 shares of Common Stock owned by
Technology II, 464,577 shares of Common Stock owned by SSFQP and 40,724 shares
of Common Stock owned by SSF3.

	(b) Percent of Class:  Messrs. Marxe and Greenhouse beneficially own
11.6% of the shares outstanding.  Cayman owns 0.9% of the outstanding shares,
Technology owns 0.7% of the outstanding shares, Technology II owns 6.3% of the
outstanding shares, SSFQP owns 3.4% of the outstanding shares and SSF3 owns
0.3% of the outstanding shares.

	(c) Number of Shares as to which the person has:

		(i)	Sole power to vote or to direct the vote:  0

		(ii)	Shared power to vote or to direct the vote:  1,584,489

		(iii)	Sole power to dispose or to direct the disposition of:  0

(iv)	Shared power to dispose or to direct the disposition of:
1,584,489


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 that five 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:  Not Applicable.

Item 8. Identification and Classification of Members of the Group:  Not
applicable

Item 9. Notices of Dissolution of Group:  Not applicable.






								Page 5 of 6 Pages

Item 10.Certification:

	By signing below I certify that, to the best of my knowledge and belief,
the securities
referred to above were acquired and are held in the ordinary course of
business and 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.

Dated: February 14, 2006



				/s/ Austin W. Marxe
				AUSTIN W. MARXE



				/s/David M Greenhouse
				DAVID M. GREENHOUSE




Attention:  Intentional misstatements or omissions of fact constitute Federal
criminal violations (See 18 U.S.C. 1001).























         								Page 6 of 6 Pages


JOINT FILING AGREEMENT


	Austin W. Marxe and David M. Greenhouse hereby agree that the Schedule
13G to which this agreement is attached is filed on behalf of each of them.



	/s/_Austin W. Marxe
Austin W. Marxe



	/s/_David M. Greenhouse
David M. Greenhouse








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