SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No.________)*
ATMI Incorporated
(Name of Issuer)
Common Stock (Par Value $0.01)
(Title of Class of Securities)
00207R101
(CUSIP Number)
Check the following box if a fee is being paid with this statement [ ].
(A fee is not required only if the filing person: (1) has a previous statement
on file reporting beneficial ownership of more than five percent of the class
of securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such
class.)(See Rule 13d-7.)
* 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 provisions of the Act (however, see
the Notes).
(Continued on following pages)
Page 1 of 6 Pages
CUSIP No. 00207R101 Page 2 of
6
1. NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Brown Investment Advisory & Trust Company ("BIATC"), its
wholly owned subsidiary, Brown Advisory Incorporated
("BAI"). 52-1811121
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A
GROUP*
(a) [ ]
(b) [x]
3. SEC USE ONLY
4. CITIZENSHIP OR PLACE OF ORGANIZATION
Brown Investment Advisory & Trust Company and Brown Advisory
Incorporated are Maryland corporations.
NUMBER OF 5 SOLE VOTING POWER
SHARES BIATC 1819182 shares
BAI 0 shares
1819182 shares
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY BIATC 0 shares
BAI 0 shares
0 shares
EACH REPORTING 7 SOLE DISPOSITIVE POWER
PERSON WITH BIATC 1868366 shares
BAI 0 shares
1868366 shares
8 SHARED DISPOSITIVE POWER
BIATC 0 shares
BAI 0 shares
0 shares
CUSIP No. 00207R101
Page 3 of 6
9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH
REPORTING PERSON
BIATC 1868366 shares
BAI 0 shares
1868366 shares
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9)
EXCLUDES CERTAIN SHARES* [ ]
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
BIATC 6.29%
BAI 0.0%
6.29%
12. TYPE OF REPORTING PERSON*
BIATC - BK
BAI - IA
*SEE INSTRUCTIONS BEFORE FILLING OUT
Item 1. (a) NAME OF ISSUER: ATMI Inc.
(b) Address of Issuer's Principal Executive Offices:
7 Commerce Drive
Danbury Connecticut 06810
Item 2. (a) NAME OF PERSON FILING:
Brown Investment Advisory & Trust Company ("BIATC"), its
wholly owned subsidiary, Brown Advisory Incorporated
("BAI").
(b) ADDRESS OF PRINCIPAL BUSINESS OFFICE:
19 South Street
Baltimore, Maryland 21202
(c) CITIZENSHIP:
Brown Investment Advisory & Trust Company and Brown
Advisory Incorporated are Maryland corporations.
CUSIP No. 00207R101
Page 4 of 6
(d) TITLE OF CLASS OF SECURITIES:
Common Stock of ($0.01 par) of ATMI Inc.
(e) CUSIP Number:
00207R101
Item 3. If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b),
check whether the person filing is a:
For BIATC
(b) [x] Bank as defined in section 3(a)(6) of the Act
For BAI
(e) [x] Investment Adviser registered under section 203 of the
Investment Advisers Act of 1940
Item 4. OWNERSHIP:
(a) AMOUNT BENEFICIALLY OWNED: As of
September 30, 2000
BIATC 1868366 shares
BAI 0 shares
1868366 shares
(b) PERCENT OF CLASS:
BIATC 6.29%
BAI 0.0%
6.29%
(c) Number of shares as to which such person has:
(i) sole power to vote or to direct the vote:
BIATC 1819182 shares
BAI 0 shares
1819182 shares
CUSIP No. 00207R101
Page 5 of 6
(ii) shared power to vote or to direct the vote:
BIATC 0 shares
BAI 0 shares
0 shares
(iii) sole power to dispose or to direct the disposition of:
BIATC 1838366 shares
BAI 0 shares
1868366 shares
(iv) shared power to dispose or to direct the disposition of:
BIATC 0 shares
BAI 0 shares
0 shares
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 GROUP.
Not applicable
CUSIP No. 00207R101
Page 6 of 6
Item 10. CERTIFICATION.
By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired in the
ordinary course of business and were not acquired for the purpose
of and do not have the effect of changing or influencing the
control of the issuer of such securities and were not acquired in
connection with or as a participant in any transaction having such
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.
Date: As of September 30,2000
Signature: Brown Investment Advisory & Trust Company
By: /S/ James E. Hieber
Title: Vice President
Signature: Brown Advisory Incorporated
By: /S/ James E. Hieber
Title: Vice President
