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Schedule 13G Page 1 of 8
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No._____)*
Natural Microsystems, CP
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(Name of Issuer)
Common
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(Title of Class of Securities)
638882100
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(CUSIP Number)
12.31.99
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(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)
[_] 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
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Page 2 of 8
Schedule 13G
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. 638882100
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NAMES OF REPORTING PERSONS.
1. I.R.S. IDENTIFICATION Nos. OF ABOVE PERSONS (ENTITIES ONLY).
Westfield Capital MGT Co. Inc. 04-3042550
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CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS)
2. (a) [_]
(b) [_]
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SEC USE ONLY
3.
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CITIZENSHIP OR PLACE OF ORGANIZATION
4.
Massachusetts
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SOLE VOTING POWER
5.
NUMBER OF 704,610
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6.
OWNED BY
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EACH SOLE DISPOSITIVE POWER
7.
REPORTING 704,610
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8.
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AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9.
704,610
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CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
10. (SEE INSTRUCTIONS)
[_]
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PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
11.
5.5147%
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TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
12.
Investment Advisor registered under the Investment Advisors Act of 1940
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Federal securities laws and rules promulgated thereunder.
GENERAL INSTRUCTIONS
A. Statements filed pursuant to Rule 13d-1(b) containing the information
required by this schedule shall be filed not later than February 14
following the calendar year covered by the statement or within the time
specified in Rules 13d-1(b)(2) and 13d-2(c). Statements filed pursuant to
Rule 13d-1(c) shall be filed within the time specified in Rules 13d-1(c),
13d-2(b) and 13d-2(d). Statements filed pursuant to Rule 13d-1(d) shall be
filed not later than February 14 following the calendar year covered by the
statement pursuant to Rules 13d-1(d) and 13d-2(b).
B. Information contained in a form which is required to be filed by rules
under section 13(f) (15 U.S.C. 78m(f)) for the same calendar year as that
covered by a statement on this schedule may be incorporated by reference in
response to any of the items of this schedule. If such information is
incorporated by reference in this schedule, copies of the relevant pages of
such form shall be filed as an exhibit to this schedule.
C. The item numbers and captions of the items shall be included but the text
of the items is to be omitted. The answers to the items shall be so
prepared as to indicate clearly the coverage of the items without referring
to the text of the items. Answer every item. If an item is inapplicable or
the answer is in the negative, so state.
Item 1.
(a) Name of Issuer Natural Microsystems
(b) Address of Issuer's Principal Executive Offices
100 Crossing Blvd
Framingham, MA 01702
Item 2.
(a) Name of Person Filing Westfield Capital Management Co., Inc.
(b) Address of Principal Business Office or, if none, Residence
One Financial Center
Boston, MA 02111
(c) Citizenship Massachusetts
(d) Title of Class of Securities Common
(e) CUSIP Number 638882100
Item 3. If this statement is filed pursuant to (S)(S)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
(S)240.13d-1(b)(1)(ii)(E);
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Schedule 13G Page 6 of 8
(f) [_] An employee benefit plan or endowment fund in accordance with
(S)240.13d-1(b)(1)(ii)(F);
(g) [_] A parent holding company or control person in accordance with
(S)240.13d-1(b)(1)(ii)(G);
(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 (S)240.13d-1(b)(1)(ii)(J).
Item 4. Ownership.
Provide the following information regarding the aggregate number and percentage
of the class of securities of the issuer identified in Item 1.
(a) Amount beneficially owned: 704,610
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(b) Percent of class: 5.5147%
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(c) Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote 704,610
--------.
(ii) Shared power to vote or to direct the vote 0
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(iii) Sole power to dispose or to direct the disposition of 704,610
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(iv) Shared power to dispose or to direct the disposition of 0
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Instruction. For computations regarding securities which represent a right to
acquire an underlying security see (S)240.13d-3(d)(1).
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 [_].
Instruction: Dissolution of a group requires a response to this item.
Item 6. Ownership of More than Five Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct
the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified. A listing of the shareholders of an investment
company
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Schedule 13G Page 7 of 8
registered under the Investment Company Act of 1940 or the beneficiaries of
employee benefit plan, pension fund or endowment fund is not required.
Item 7. Identification and Classification of the Subsidiary Which Acquired the
Security Being Reported on By the Parent Holding Company
If a parent holding company has filed this schedule, pursuant to Rule 13d-
1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the
identity and the Item 3 classification of the relevant subsidiary. If a parent
holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-
1(d), attach an exhibit stating the identification of the relevant subsidiary.
Item 8. Identification and Classification of Members of the Group
If a group has filed this schedule pursuant to (S)240.13d-1(b)(1)(ii)(J), so
indicate under Item 3(j) and attach an exhibit stating the identity and Item 3
classification of each member of the group. If a group has filed this schedule
pursuant to (S)240.13d-1(c) or (S)240.13d-1(d), attach an exhibit stating the
identity of each member of the group.
Item 9. Notice of Dissolution of Group
Notice of dissolution of a group may be furnished as an exhibit stating the date
of the dissolution and that all further filings with respect to transactions in
the security reported on will be filed, if required, by members of the group, in
their individual capacity. See Item 5.
Item 10. Certification
(a) The following certification shall be included if the statement is
filed pursuant to (S)240.13d-1(b):
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.
(b) The following certification shall be included if the statement is
filed pursuant to (S)240.13d-1(c):
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.
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Schedule 13G Page 8 of 8
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.
2.7.00
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Date
/s/ Karen DiGravio
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Signature
Karen DiGravio, Treasurer
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Name/Title
The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.
NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See (S)240.13d-7 for other
parties for whom copies are to be sent.
Attention: Intentional misstatements or omissions of fact constitute Federal
criminal violations (See 18 U.S.C. 1001)
