SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
_________________
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No.) /6/
Pac-West Telecomm, Inc.
(Name of Issuer)
Common Stock, par value $0.001 per share
(Title of Class of Securities)
69371Y 10 1
(CUSIP Number)
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)
|_| Rule 13d-1(c)
|X| Rule 13d-1(d)
___________
/1/ 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 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. 69371Y 10 1 Page 2 of 7 Pages
13G
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1. NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
William Blair Capital Partners VI, L.P.
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2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
(a) |_|
(b) |_|
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3. SEC USE ONLY
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4. CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
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NUMBER OF 5. SOLE VOTING POWER
SHARES 0
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BENEFICIALLY 6. SHARED VOTING POWER
OWNED BY 3,652,649 (See Item 4)
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EACH 7. SOLE DISPOSITIVE POWER
REPORTING 0
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PERSON 8. SHARED DISPOSITIVE POWER
WITH 3,652,649 (See Item 4)
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9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,652,649 (See Item 4)
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10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
|_|
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11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
9.83%
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12. TYPE OF REPORTING PERSON*
PN
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*SEE INSTRUCTION BEFORE FILLING OUT!
CUSIP No. 69371Y 10 1 Page 3 of 7 Pages
13G
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1. NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
William Blair Capital Partners VI, L.L.C.
--------------------------------------------------------------------------------
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
(a) |_|
(b) |_|
--------------------------------------------------------------------------------
3. SEC USE ONLY
--------------------------------------------------------------------------------
4. CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
--------------------------------------------------------------------------------
NUMBER OF 5. SOLE VOTING POWER
SHARES 0
-----------------------------------------------------------------
BENEFICIALLY 6. SHARED VOTING POWER
OWNED BY 3,652,649 (See Item 4)
-----------------------------------------------------------------
EACH 7. SOLE DISPOSITIVE POWER
REPORTING 0
-----------------------------------------------------------------
PERSON 8. SHARED DISPOSITIVE POWER
WITH 3,652,649 (See Item 4)
--------------------------------------------------------------------------------
9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
3,652,649 (See Item 4)
--------------------------------------------------------------------------------
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
|_|
--------------------------------------------------------------------------------
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
9.83%
--------------------------------------------------------------------------------
12. TYPE OF REPORTING PERSON*
OO
--------------------------------------------------------------------------------
*SEE INSTRUCTION BEFORE FILLING OUT!
SCHEDULE 13G
Item 1(a). Name of Issuer:
Pac-West Telecomm, Inc. (the "Company")
Item 1(b). Address of Issuer's Principal Executive Offices:
4210 Coronado Avenue
Stockton, California 95204
Item 2(a). Name of Persons Filing:
This statement is filed jointly by each of the following Persons pursuant
to Rule 13d-1(k) promulgated by the Securities and Exchange Commission
("SEC") under Section 13 of the Securities Exchange Act of 1934, as
amended (the "Act"): (i) William Blair Capital Partners VI, L.P., a
Delaware limited partnership (the "Fund"), by virtue of its direct
beneficial ownership of Common Stock and (ii) William Blair Capital
Partners VI, L.L.C. ("WBCPCO," together with the Fund, each a "Reporting
Person" and collectively, "Reporting Persons"), a Delaware limited
liability company, by virtue of its being the general partner of the Fund.
By virtue of being members of the Board of Managers of WBCPCO (the
"Board"), Timothy Burke, John Ettelson, Robert D. Blank, David G.
Chandler, Edgar D. Jannotta, Arda Minocherhomjee, Timothy M. Murray, and
Thomas C. Theobald may be deemed to possess indirect beneficial ownership
of the Common Stock, but such beneficial ownership is disclaimed. Only the
Board, acting upon the consent of a majority of the members of the Board
at any meeting of the Board where a quorum is present, possesses the right
to vote, direct the vote, dispose or direct the disposition of the Common
Stock. No individual has sole power to vote, direct the vote, dispose or
direct the disposition of the Common Stock. The Reporting Persons have
entered into an Agreement Related to the Joint Filing of Schedule 13G,
dated February 9, 2006, a copy of which is filed with this Schedule 13G as
Exhibit A, pursuant to which the Reporting Persons have agreed to file
this statement jointly in accordance with the provisions of Rule 13d-1(k)
under the Act. Information with respect to each of the Reporting Persons
is given solely by such Reporting Person, and no Reporting Person assumes
responsibility for the accuracy or completeness of information provided by
another Reporting Person. By their signature on this statement, each of
the Reporting Persons agrees that this statement is filed on behalf of
such Reporting Person. The Reporting Persons may be deemed to constitute a
"group" for purposes of Section 13(d)(3) of the Act. The Reporting Persons
expressly disclaim that they have agreed to act as a group other than as
described in this statement.
Item 2(b). Address of Principal Business Office or, if none, Residence:
The address of the principal business office of each of the
Reporting Persons is 222 West Adams Street, Chicago, Illinois 60606.
Item 2(c). Citizenship:
The Fund is a Delaware limited partnership and WBCPCO is a Delaware
limited liability company.
Item 2(d). Title of Class of Securities:
Common Stock, par value $0.001 per share ("Common Stock").
Item 2(e). CUSIP No.:
69371Y 10 1
Item 3. If this statement is filed pursuant to Rules 13d-1(b) or
13d-2(b) or (c), check whether the person filing is a:
Not Applicable.
Item 4. Ownership (as of December 31, 2005):
As of December 31, 2005, the Fund was the registered owner Of
3,652,649 shares of Common Stock or approximately 9.83% of the total
number of shares of Common Stock outstanding as of such date (based
upon information provided by the Company). By virtue of the
relationship between the Fund and WBCPCO described in Item 2(a),
WBCPCO may be deemed to possess indirect beneficial ownership of and
shares the power to vote or direct the vote of the shares of Common
Stock beneficially owned by the Fund. WBCPCO disclaims beneficial
ownership of the shares of Common Stock owned by the Fund. The
filing of this statement by WBCPCO shall not be construed as an
admission that they are, for the purpose of Section 13(d) or Section
13(g) of the Act, the beneficial owner of any securities covered by
this statement.
Page 4 of 7
Item 5. Ownership of Five Percent or Less of a Class:
Not Applicable.
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. Notice of Dissolution of a Group:
Not Applicable.
Item 10. Certification:
Not Applicable.
Page 5 of 7
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.
Date: February 9, 2006
William Blair Capital Partners
VI, L.P.
By: William Blair Capital
Partners VI, L.L.C., its
general partner
By: /s/ David G. Chandler
---------------------------
Its: Managing Director
William Blair Capital Partners
VI, L.L.C.
By: /s/ David G. Chandler
---------------------------
Its: Managing Director
Page 6 of 7
EXHIBIT A
AGREEMENT REGARDING THE JOINT FILING OF
SCHEDULE 13G
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William Blair Capital Partners VI, L.P. and William Blair Capital Partners VI,
L.L.C. hereby agree that the Statement on Schedule 13G to which this agreement
is attached as an exhibit, as well as all future amendments to such Statement,
shall be filed jointly on behalf of each of them. This agreement is intended to
satisfy the requirements of Rule 13d-1(k)(1)(iii) under the Securities Exchange
Act of 1934, as amended.
Date: February 9, 2006
William Blair Capital Partners
VI, L.P.
By: William Blair Capital
Partners VI, L.L.C., its
general partner
By: /s/ David G. Chandler
----------------------------
Its: Managing Director
William Blair Capital Partners
VI, L.L.C.
By: /s/ David G. Chandler
----------------------------
Its: Managing Director
Page 7 of 7