UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G/A
Under the Securities Exchange Act of 1934
Amendment 1 Filing
(Name of Issuer)
Costar Group, Inc.
(Title of Class of Securities)
Common Stock
(Cusip Number)
22160N109
(Date of Event Which Requires Filing of this Statement)
12/31/2006
Check the appropriate box to designate the rule pursuant to which this
Schedule is Filed:
[ x ] 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 provision of the Act (however, see the Notes).
Cusip Number
22160N109
1. Name of Reporting Persons. I.R.S. identification Nos. of above persons
(entities only)
Next Century Growth Investors, LLC - 41-1923871
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
Delaware
Number of shares beneficially owned by each reporting person with:
5. Sole Voting Power
0
6. Shared Voting Power
455,050
7. Sole Dispositive Power
0
8. Shared Dispositive Power
455,050
9. Aggregate Amount Beneficially Owned by Each Reporting Person
2.40%
10. Check if the Aggregate Amount in Row (11) Excludes Certain
Shares (See Instructions)
N/A
11. Percent of Class Represented by Amount in Row (11)
2.40%
12. Type of Reporting Person (See Instructions)
Cusip Number
22160N109
1. Name of Reporting Persons.
I.R.S. identification Nos. of above persons (entities only)
Thomas L. Press
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
U.S.A.
Number of shares beneficially owned by each reporting person with:
5. Sole Voting Power
0
6. Shared Voting Power
455,050
7. Sole Dispositive Power
0
8. Shared Dispositive Power
455,050
9. Aggregate Amount Beneficially Owned by Each Reporting Person
2.40%
10. Check if the Aggregate Amount in Row (11) Excludes Certain
Shares (See Instructions)
N/A
11. Percent of Class Represented by Amount in Row (11)
2.40%
12. Type of Reporting Person (See Instructions)
IN
Item 1(a). The name of the issuer is:
Costar Group, Inc.
Item 1(b). The principal executive office of the issuer is:
2 Bethesda Metro Center Bethesda, MD 20814
Item 2(a). The names of the persons filing this statement are:
Next Century Growth Investors, LLC, Thomas L. Press and Donald
M. Longlet The persons filing this Schedule 13G have entered into a Joint
Filing Agreement, a copy of which is filed with this statement as Exhibit 1,
pursuant to which such persons have agreed to file this Schedule 13G jointly
in accordance with the provisions of Rule 13d-1(k) of the Securities
Exchange Act of 1934. The persons filing this Schedule 13G are of the
view that they are not acting as a "group" for purposes of Section 13(d)
under the Securities Exchange Act of 1934. Item 2(b). The Principal
business office of Next Century Growth Investors, LLC Thomas L. Press
and Donald M. Longlet is: 5500 Wayzata Blvd., Suite 1275 Minneapolis,
MN 55416
Item 2(c). Next Century Growth Investors, LLC is a Delaware limited
liability company and Thomas L. Press and Donald M. Longlet are citizens
of the U.S.A.
Item 2(d). This Statement relates to shares of the common stock of the
Issuer (the ""Stock"")
Item 2(e). The CUSIP number of the Stock is:
22160N109
"Item 3. If this statement is filed pursuant to ss.ss.240.13d-1(b) or 240.13d-
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). [ x ] An investment adviser in accordance with ss.240.13d-
1(b)(1)(ii)(E).
"This Schedule 13G is being filed by Next Century Growth
Investors, LLC as a registered investment adviser. The Stock to which this
Schedule 13G relates is held in investment advisory accounts of Next
Century Growth Investors, LLC.
(f). [ ] An employee benefit plan or endowment fund in accordance with
ss.240.13d-1(b)(1)(ii)(G).
(g). [ x ] A parent holding company or control person in accordance with
ss.240.13d-1(b)(1)(ii)(G).
"This Schedule 13G is also being filed by Thomas L. Press, who
serves as Director, Chairman and Chief Executive Officer of Next Century
Growth Investors, LLC and Donald M. Longlet, who serves as Director and
President of Next Century Growth Investors, LLC. Mr. Press owns in
excess of 25% of Next Century Growth Investors, LLC and is a controlling
person of Next Century Growth Investors, LLC.
(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 ss.240.13d-1(b)(1)(ii)(J)."
Item 4. Ownership*
The Stock to which this Schedule 13G relates may be deemed
beneficially ownedwithin the meaning of Rule 13d-3 of the Securities
Exchange Act of 1934 by (1) Next Century Growth Investors, LLC by
virture of its investment discretion and/or voting power over client
securities, which may be revoked; and (2) Thomas L. Press and Donald M.
Longlet, as a result of their positions with and ownership positions in Next
Century Growth Investors, LLC, which could be deemed to confer upon
eachof them voting and/or investment power over the shares. Each of Next
Century Growth Investors, LLC, Thomas L. Press and Donald M. Longlet
disclaim beneficial ownership of the Stock except to the extent of each of
their respective pecuniary interested therein, if any, and the filing of this
Schedule 13G shall not be construed as an admission by any of such persons
that it is the beneficial owner of the Stock.
See Items 5-9 and 11 on the cover page for each filer.
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 [ ].
Item 6. The Stock to which this Schedule 13G relates is held in investment
advisory accounts of Next Century Growth, LLC. As a result, various
persons have the right to receive or the power to direct the receipt of
dividends from, or the proceeds from the sale of, the securities. No such
account is known to have such an interest relating to more than 5% of the
class.
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. Notice of Dissolution of Group:
Not Applicable
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 our knowledge and belief, the
undersigned certify that the information set forth in this statement is true,
complete and correct.
Dated: February 14, 2007
Next Century Growth Investors, LLC
By: /s/ Thomas L. Press
Thomas L. Press
Chief Executive Officer
By: /s/ Donald M. Longlet
Donald M. Longlet
President
Exhibit A
JOINT FILING AGREEMENT
In accordance with Rule 13d-1(k) under the Securities Exchange Act of
1934, the undersigned persons agree and consent to the joint filing on their
behalf of a statement on Schedule 13G, including amendments thereto, in
connection with respect to shares of common stock of
Costar Group, Inc.
IN WITNESS WHEREOF, the parties have executed this Joint Filing
Agreement on February 14, 2007.
NEXT CENTURY GROWTH INVESTORS, LLC
By: /s/ Thomas L. Press
Thomas L. Press, Chief Executive Officer
THOMAS L. PRESS
By: /s/ Thomas L. Press
Thomas L. Press
DONALD M. LONGLET
By: /s/ Donald M. Longlet
Donald M. Longlet