SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

_____________

FORM 8-A

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

PURSUANT TO SECTION 12(b) OR 12(g) OF THE

SECURITIES EXCHANGE ACT OF 1934

Sigma-Aldrich Corporation

Securities Act registration statement file number to which this form relates: (If applicable)
 
 

Securities to be registered pursuant to Section 12(b) of the Act:

Securities to be registered pursuant to Section 12(g) of the Act:
 

Common Stock Purchase Rights

Item 1. Description of Registrant's Securities to be Registered.

On August 8, 2000, the Board of Directors of Sigma-Aldrich Corporation (the "Company") declared a dividend of one common share purchase right (a "Right") for each outstanding share of Common Stock, par value $1.00 per share, of the Company (the "Common Stock"). The dividend distribution is payable on August 22, 2000 (the "Record Date") to the stockholders of record as of the close of business on that date. Each Right entitles the registered holder to purchase from the Company one share of Common Stock at a price of $150.00 per share (the "Purchase Price"), subject to adjustment. The description and terms of the Rights are set forth in a Rights Agreement dated as of August 8, 2000, as the same may be amended from time to time (the "Rights Agreement"), between the Company and Computershare Investor Services, LLC, as Rights Agent (the "Rights Agent").

Until the earlier to occur of (i) the close of business on the tenth business day following the date of public announcement or the date on which the Company first has notice or determines that a person or group of affiliated or associated persons (other than the Company, any subsidiary of the Company or any employee benefit plan of the Company) (an "Acquiring Person") has acquired, or obtained the right to acquire, 15% or more of the outstanding shares of voting stock of the Company without the prior express written consent of the Company executed on behalf of the Company by a duly authorized officer of the Company following express approval by action of at least a majority of the members of the Board of Directors then in office (the "Stock Acquisition Date") or (ii) the close of business on the tenth business day (or such later date as may be determined by action of the Board of Directors but not later than the Stock Acquisition Date) following the commencement of a tender offer or exchange offer, without the prior written consent of the Company, by a person (other than the Company, any subsidiary of the Company or any employee benefit plan of the Company) which, upon consummation, would result in such party's control of 15% or more of the Company's voting stock (the earlier of the dates in clause (i) or (ii) above being called the "Distribution Date"), the Rights will be evidenced, with respect to any of the Common Stock certificates outstanding as of the Record Date, by such Common Stock certificates.

The Rights Agreement provides that, until the Distribution Date (or earlier redemption or expiration of the Rights), the Rights will be transferred with and only with the Company's Common Stock. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), new Common Stock certificates issued after the Record Date upon transfer or new issuances of Common Stock will contain a notation incorporating the Rights Agreement by reference. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), the surrender for transfer of any certificates for shares of Common Stock outstanding as of the Record Date, even without such notation or a copy of this Summary of Rights, will also constitute the transfer of the Rights associated with the Common Stock represented by such certificate. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights ("Right Certificates") will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and such separate certificates alone will then evidence the Rights.

The Rights are not exercisable until the Distribution Date. The Rights Agreement requires the Board of Directors to review the Rights after they have been outstanding for four years, provided they have not then become exercisable, to determine whether they should be terminated or left in effect. The Rights will expire, if not previously exercised or if the Rights Agreement has not been terminated following such review, on August 8, 2010 (the "Final Expiration Date"), unless the Final Expiration Date is extended or unless the Rights are earlier redeemed or exchanged by the Company.

The Purchase Price payable, and the number of shares of Common Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of the Common Stock, (ii) upon the issuance of Common Stock or rights to subscribe for shares of Common Stock, or securities convertible into Common Stock with a conversion price of less than the then-current market price of the Common Stock or (iii) upon the distribution to holders of Common Stock of securities (other than those described in (ii) above), evidences of indebtedness or assets (excluding regular periodic cash dividends or dividends out of earnings or retained earnings).

If any person or group (other than the Company, any subsidiary of the Company, any employee benefit plan of the Company) acquires 15% or more of the Company's outstanding voting stock without the prior written consent of the Board of Directors, each Right, except those held by such persons, would entitle each holder of a Right to acquire such number of shares of the Company's Common Stock as shall equal the result obtained by multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable and dividing that product by 50% of the then current per-share market price of Company Common Stock.

If any person or group (other than the Company, any subsidiary of the Company, or any employee benefit plan of the Company) acquires more than 15% but less than 50% of the outstanding Company Common Stock without prior written consent of the Board of Directors, each Right, except those held by such persons, may be exchanged by the Board of Directors for one share of Company Common Stock.

If the Company were acquired in a merger or other business combination transaction where the Company is not the surviving corporation or where Company Common Stock is exchanged or changed or 50% or more of the Company's assets or earnings power is sold in one or several transactions without the prior written consent of the Board of Directors, each Right would entitle the holders thereof (except for the Acquiring Person) to receive such number of shares of the acquiring company's common stock as shall be equal to the result obtained by multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable and dividing that product by 50% of the then current market price per share of the common stock of the acquiring company on the date of such merger or other business combination transaction.

With certain exceptions, no adjustment in the Purchase Price will be required until cumulative adjustments require an adjustment of at least 1% in such Purchase Price. No fractional shares of Common Stock will be issued. In lieu of fractional shares, an adjustment in cash will be made based on the market price of the Common Stock on the last trading day prior to the date of exercise.

At any time prior to the tenth Business Day following the time an Acquiring Person becomes such, the Board of Directors of the Company may redeem the Rights in whole, but not in part, at a price of $0.01 per Right (the "Redemption Price"). The redemption of the Rights may be made effective at such time, on such basis and with such conditions as the Board of Directors in its sole discretion may establish. Immediately upon any redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price.

The terms of the Rights may be amended by the Board of Directors of the Company without the consent of the holders of the Rights, including, but not limited to, an amendment to lower certain thresholds described above to not less than the greater of (i) any percentage greater than the largest percentage of the voting power of all securities of the Company then known to the Company to be beneficially owned by any person or group of affiliated or associated persons (other than an excepted person) and (ii) 10%, except that from and after such time as any person or group of affiliated or associated persons becomes an Acquiring Person no such amendment may adversely affect the interests of the holders of the Rights.

Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends.

The Rights Agreement between the Company and the Rights Agent specifying the terms of the Rights, which includes as Exhibit A thereto the form of Right Certificate, is attached hereto as Exhibit 1 and is incorporated herein by reference. The foregoing description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement (and the exhibits thereto) attached hereto.

Item 2. Exhibits.
 

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereto duly authorized.
 

SIGMA-ALDRICH CORPORATION

(Registrant)