natus13da-041811.htm
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549


SCHEDULE 13D
Under the Securities Exchange Act of 1934
(Amendment No. 16)


NATUS MEDICAL INCORPORATED (BABY)
(Name of Issuer)


Common Stock
(Title of Class of Securities)

639050103
(CUSIP Number)

David Nierenberg
The D3 Family Funds
19605 NE 8th Street
Camas, WA  98607
(360) 604-8600

With a copy to:

Christopher P. Davis
Kleinberg, Kaplan, Wolff & Cohen, P.C.
551 Fifth Avenue
New York, NY 10176
(212) 986-6000

______________________________________
(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

April 14, 2011
(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box [  ]Ô.


 
 
 



1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
The D3 Family Fund, L.P.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
WC
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Washington
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
286,521 common shares (1.0%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
286,521
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 286,521; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page,1.0%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
PN


 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
The D3 Family Bulldog Fund, L.P.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
WC
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Washington
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
1,147,026 common shares (4.0%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
1,147,026
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 1,147,026; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 4.0%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
PN

 
 
 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
The D3 Family Canadian Fund, L.P.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
WC
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Washington
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
129,931 common shares (0.4%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
129,931
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 129,931; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 0.4%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
PN

 
 
 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
The DIII Offshore Fund, L.P.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
WC
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Bahamas
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
221,964 common shares (0.8%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
221,964
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 221,964; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 0.8%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
PN

 
 
 
 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
Nierenberg Investment Management Company, Inc.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
AF
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Washington
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
1,785,442 shares (6.2%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
1,785,442 shares
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 1,785,442; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 6.2%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
CO


 
 
 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
Nierenberg Investment Management Offshore, Inc.
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
AF
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
Bahamas
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
221,964 common shares (0.8%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
221,964 common shares
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 221,964; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 0.8%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
CO

 
 
 
 
 
 

1
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
 
David Nierenberg
 
2
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
                                    (a) [X]
                                    (b) [  ]
 
3
SEC USE ONLY
 
  
4
SOURCE OF FUNDS (See Instructions)
AF
5
CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e) [   ]
 
 
6
CITIZENSHIP OR PLACE OF ORGANIZATION
United States of America
NUMBER OF SHARES
BENEFICIALLY
7
SOLE VOTING POWER
0
OWNED BY
EACH
REPORTING
8
SHARED VOTING POWER
1,785,442 common shares (6.2%)
 
PERSON
WITH
 
9
SOLE DISPOSITIVE POWER
0
 
10
SHARED DISPOSITIVE POWER
1,785,442 
11
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
For the reporting person listed on this page, 1,785,442; for all reporting persons as a group, 1,785,442 shares (6.2%)
12
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)
 
13
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
For the reporting person listed on this page, 6.2%; for all reporting persons as a group 6.2%
14
TYPE OF REPORTING PERSON (See Instructions)
IN


 
 
 

This Amendment No. 16 to Schedule 13D (this “Amendment”) amends the below-indicated Items from the Schedule 13D with respect to the shares of common stock (the “Common Stock”) of Natus Medical Incorporated (the “Issuer” or “BABY”) previously filed by or on behalf of the Reporting Persons (as defined below), as previously amended (collectively the “Schedule 13D”), by supplementing such Items with the information below.
 
The names of the persons filing this Amendment (collectively, the “Reporting Persons”) are:  The D3 Family Fund, L.P. (the “Family Fund”), The D3 Family Bulldog Fund, L.P. (the “Bulldog Fund”), The D3 Family Canadian Fund, L.P. (the “Canadian Fund”), The DIII Offshore Fund, L.P. (the “Offshore Fund”), Nierenberg Investment Management Company, Inc. (“NIMCO”), Nierenberg Investment Management Offshore, Inc. (“NIMO”) and David Nierenberg (“Mr. Nierenberg”).
 

Item 5.  Interest in Securities of the Issuer.

(a)           The Reporting Persons, in the aggregate, beneficially own 1,785,442 shares of Common Stock, constituting approximately 6.2% of the outstanding shares.
 
(b)           The Family Fund, NIMCO and Mr. Nierenberg have shared power (i) to vote or direct the vote of, and (ii) to dispose or direct the disposition of, the 286,521 shares of Common Stock held by the Family Fund.
 
The Bulldog Fund, NIMCO and Mr. Nierenberg have shared power (i) to vote or direct the vote of, and (ii) to dispose or direct the disposition of, the 1,147,026 shares of Common Stock held by the Bulldog Fund.
 
The Canadian Fund, NIMCO and Mr. Nierenberg have shared power (i) to vote or direct the vote of, and (ii) to dispose or direct the disposition of, the 129,931 shares of Common Stock held by the Canadian Fund.
 
The Offshore Fund, NIMO, NIMCO and Mr. Nierenberg have shared power (i) to vote or direct the vote of, and (ii) to dispose or direct the disposition of, the 221,964 shares of Common Stock held by the Offshore Fund.
 

 
 
 


 
(c)  Since our last Amendment to Schedule 13D the following sales of shares of Common Stock were made by the Reporting Persons named below in open market transactions:
 
 
 
 
Fund
Trade Date
QTY
 Price
D3 Family Fund, LP
04/01/2011
1,500
     17.01
D3 Family Bulldog Fund, LP
04/01/2011
6,805
     17.01
D3 Family Fund, LP
04/04/2011
11,900
     17.15
D3 Family Bulldog Fund, LP
04/04/2011
45,338
     17.15
D3 Family Fund, LP
04/05/2011
3,100
     17.13
D3 Family Bulldog Fund, LP
04/05/2011
13,482
     17.13
D3 Family Fund, LP
04/06/2011
4,861
     17.20
D3 Family Bulldog Fund, LP
04/06/2011
20,000
     17.20
D3 Family Fund, LP
04/07/2011
4,500
     17.18
D3 Family Bulldog Fund, LP
04/07/2011
17,334
     17.18
D3 Family Fund, LP
04/08/2011
7,155
     17.34
D3 Family Bulldog Fund, LP
04/08/2011
29,300
     17.34
D3 Family Fund, LP
04/11/2011
9,000
     17.29
D3 Family Bulldog Fund, LP
04/11/2011
35,714
     17.29
DIII Offshore Fund, LP
04/11/2011
1,500
     17.29
D3 Family Fund, LP
04/12/2011
4,200
     17.24
D3 Family Bulldog Fund, LP
04/12/2011
17,800
     17.24
DIII Offshore Fund, LP
04/12/2011
3,012
     17.24
DIII Offshore Fund, LP
04/13/2011
100
     17.25
D3 Family Fund, LP
04/14/2011
27,000
     16.78
D3 Family Bulldog Fund, LP
04/14/2011
109,000
     16.78
DIII Offshore Fund, LP
04/14/2011
21,835
     16.78
D3 Family Fund, LP
04/15/2011
1,618
     16.88
D3 Family Bulldog Fund, LP
04/15/2011
6,000
     16.88
DIII Offshore Fund, LP
04/15/2011
1,000
     16.88

 
 
 

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, each of the undersigned certifies that the information set forth in the Statement is true, complete and correct.
 
                                                                                                        D3 Family Fund, L.P., D3 Family Bulldog Fund, L.P., and D3 Family Canadian Fund, L.P.
 
                                                                                                     By:  Nierenberg Investment Management Company, Inc.
 
                                                                                                       Its:   General Partner
April 18, 2011                                                                               By: /s/ David Nierenberg
-------------------------                                                                    -------------------------------------------------
                                                                                                                     David Nierenberg, President
 
                                                                                                        DIII Offshore Fund, L.P.
 
                                                                                                     By:  Nierenberg Investment Management Offshore, Inc.
 
                                                                                                       Its:   General Partner
April 18, 2011                                                                               By: /s/ David Nierenberg
-------------------------                                                                    -------------------------------------------------
                                                                                                                     David Nierenberg, President
 
                                                                                
                                                                                                    Nierenberg Investment Management Company, Inc.
                                                                                
April 18, 2011                                                                               By: /s/ David Nierenberg
-------------------------                                                                    -------------------------------------------------
                                                                                                                    David Nierenberg, President
 
                                                                                
                                                                                                     Nierenberg Investment Management Offshore, Inc.

April 18, 2011                                                                               By: /s/ David Nierenberg
-------------------------                                                                    -------------------------------------------------
                                                                                                                    David Nierenberg, President
 
 
April 18, 2011                                                                               /s/ David Nierenberg
-------------------------                                                                    ----------------------------
                                                                                                            David Nierenberg