8-A12G/A

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                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.   20549

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                                   FORM 8-A/A
                                AMENDMENT NO. 4




               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                   PURSUANT TO SECTION 12(b) OR 12(g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934
                               
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                             SUN MICROSYSTEMS, INC.
             (Exact name of Registrant as specified in its charter)


               Delaware                                  94-2805249
      (State of Incorporation)                       (I.R.S. Employer
                                                   Identification Number)


            2550 Garcia Avenue
        Mountain View, California                        94043-1100
 (Address of principal executive offices)                (Zip Code)



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

            Title of each class                   Name of each exchange on     
            to be so registered            which each class is to be registered
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                   NONE                                   NONE


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

                         COMMON SHARE PURCHASE RIGHTS
                         ----------------------------
                               (Title of Class)

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Item 1.       Description of Securities to be Registered.

        On April 26, 1989, the Board of Directors of Sun Microsystems, Inc.
(the "Company") declared a dividend of one common share purchase right (a
"Right") for each outstanding share of Common Stock, $.00067 par value (the
"Common Shares"), of the Company.  The dividend was paid on May 26, 1989 (the
"Record Date") to stockholders of record as of the close of business on that
date, and Rights have been issued in connection with all Common Shares issued
since that date.  Each Right entitles the registered holder to purchase from
the Company one Common Share at a price of $100.00 (the "Purchase Price"),
subject to adjustment.  The description and terms of the Rights are set forth
in a First Amended and Restated Common Shares Rights Agreement dated as of
December 14, 1990 between the Company and The First National Bank of Boston as
Rights Agent (the "Amended Rights Agreement"), as amended by the Amendment
dated as of October 2, 1991 (the "First Amendment"), the Second Amendment dated
August 5, 1992 (the "Second Amendment") and the Third Amendment dated November
2, 1994 (the "Third Amendment").

        The following is a general description only and is subject to the
detailed terms and conditions of the Amended Rights Agreement, the First
Amendment, the Second Amendment and the Third Amendment (collectively referred
to herein as the "Amended Rights Agreement").  A copy of the Amended Rights
Agreement, including the form of Rights Certificate and the Summary of Terms
provided to stockholders of the Company, the First Amendment, the Second
Amendment and the Third Amendment, are attached as Exhibits 1, 2, 3 and 4,
respectively, to this Registration Statement and are incorporated herein by
reference.

Rights Evidenced by Common Share Certificates

        The Rights will not be exercisable until the Distribution Date (defined
below).  Certificates for the Rights ("Rights Certificates") have not been, and
until after the Distribution Date will not be, sent to stockholders.  Until
after the Distribution Date, Rights will remain attached to and trade only
together with the Common Shares.  Accordingly, Common Share certificates
outstanding on the Record Date evidence the Rights related thereto, and Common
Share certificates issued after the Record Date contain a notation
incorporating the Amended Rights Agreement by reference.  Until the
Distribution Date (or earlier redemption or expiration of the Rights), the
surrender or transfer of any certificates for Common Shares outstanding as of
or after the Record Date, even without notation or a copy of the Summary of
Terms being attached thereto, also constitutes the transfer of the Rights
associated with the Common Shares represented by such certificates.

Distribution Date

        The Rights will separate from the Common Shares, Rights Certificates
will be issued and the Rights will become exercisable upon the earlier of:
 (i) 10 days (or such later date as may be determined by a majority of the
Board of Directors, excluding directors affiliated with the Acquiring Person,
as defined below (the "Continuing Directors")) following a public announcement
(which for purposes of this definition shall include, without limitation, a
report filed pursuant to Section 13(d) under the Exchange Act, except as set
forth below) by the Company or an Acquiring Person that an Acquiring Person
has become such, provided that, if such person is determined not to have become
an Acquiring Person pursuant to the definition of Acquiring Person below, then
no acquisition shall be deemed to have occurred or  (ii) 10 business days (or
such later date as may be determined by a majority of the Continuing Directors)
following the com-


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mencement of, or announcement of an intention to make, a tender offer or 
exchange offer the consummation of which would result in the beneficial 
ownership by a person or group of 30% or more of the outstanding Common 
Shares. The earlier of such dates is referred to as the "Distribution Date."

        "Acquiring Person" shall mean any person who or which, together with
all affiliates and associates of such person, shall be the beneficial owner
of 10% or more of the Common Shares then outstanding, but shall not include
the Company.  No person shall become an "Acquiring Person" if as the result
of an acquisition of Common Shares by the Company which, by reducing the number
of shares outstanding, increases the proportionate number of shares
beneficially owned by such person to 10% or more of the Common Shares of the 
Company then outstanding; provided, however, that if a person shall become 
the beneficial owner of 10% or more of the Common Shares of the Company then 
outstanding by reason of share purchases by the Company and shall, after such 
purchases by the Company, become the beneficial owner of any additional 
Common Shares of the Company, then such person shall be deemed to be an 
"Acquiring Person."  Notwithstanding the foregoing, no person shall become 
an "Acquiring Person" if such person would have become an "Acquiring Person" 
inadvertently but for the operation of this sentence and such person is the 
beneficial owner of less than 10% of the outstanding Common Shares within 
five trading days after communicating to the Board of Directors of the 
Company such person's Common Shares ownership position and the inadvertent 
nature of that position.

        In addition, notwithstanding the foregoing, a person or group of
affiliated or associated persons who acquires or obtains the right to acquire
beneficial ownership of 10% or more but less than 20% of the Common Shares then
outstanding AND files a Schedule 13G rather than a Schedule 13D in accordance
with  Section 13(d) or Rule 13(d)(1) of the Exchange Act with respect to such
Common Shares shall not be deemed to have acquired "beneficial ownership" of
such Common Shares for purposes of the Amended Rights Agreement and therefore,
will not be deemed to be an "Acquiring Person" under the Amended Rights
Agreement, but only for so long as such person or group beneficially owns less
than 20% of the then outstanding Common Shares or is not otherwise required to 
file a Schedule 13D under the Exchange Act, as may be determined by the Board
of Directors.

Issuance of Rights Certificates; Expiration of Rights

        As soon as practicable following the Distribution Date, separate Rights
Certificates will be mailed to holders of record of the Common Shares as of the
close of business on the Distribution Date and such separate Rights
Certificates alone will evidence the Rights from and after the Distribution
Date.  Unless otherwise specified by the Board of Directors at the time of
issuance, all Common Shares issued prior to the Distribution Date will be
issued with Rights.  Common Shares issued after the Distribution Date may 
be issued with Rights if such shares are issued (i) upon the conversion of 
securities issued after adoption of the original Common Shares Rights 
Agreement (dated as of May 15, 1989) or (ii) pursuant to the exercise of 
stock options or under employee benefit plans or pursuant to the conversion 
of the Company's outstanding convertible subordinated debentures unless 
such issuance would result in (or create a risk of) such options, plans or 
debentures failing to qualify for otherwise available special tax treatment.  
Except as otherwise determined by the Board of Directors, no other Common 
Shares issued after the Distribution Date will be issued with Rights.  The 
Rights will expire on the earliest of (i) May 25, 1999 (the "Final Expiration 
Date"), (ii) redemption or exchange of the Rights as described below 


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or (iii) consummation of an acquisition of the Company satisfying certain 
conditions by a person who acquired shares pursuant to a Permitted Offer 
as described below.

Initial Exercise of the Rights

        Following the Distribution Date, and until one of the further events
described below, holders of the Rights will be entitled to receive, upon
exercise and the payment of $100.00 per Right, one Common Share.

        In the event that the Company does not have sufficient Common Shares
available for all Rights to be exercised, or the Board decides that such action
is necessary and not contrary to the interests of Rights holders, the Company
may instead substitute cash, assets or other securities for the Common Shares
into which the Rights would have been exchangeable under this provision or
as described below.

Protection Against Certain Acquisitions Not Negotiated with the Board of
Directors; Right to Buy Common Shares at Half Price

        Unless the Rights are earlier redeemed, in the event that a person
becomes the beneficial owner of 10% or more of the Company's Common Shares
then outstanding (other than pursuant to a tender offer deemed fair by the
Board of Directors (a "Permitted Offer")), then proper provision will be made
so that each holder of a Right which has not theretofore been exercised (other
than Rights beneficially owned by the Acquiring Person, which will thereafter
be void) will thereafter have the right to receive, upon exercise, Common
Shares having a value equal to two times the Purchase Price. Rights are not
exercisable following the occurrence of the event set forth above until the 
Distribution Date.

Protection Against Certain Unfair Two-Step or Coercive Transactions; Right
to Buy Acquiring Company Stock at Half Price

Similarly, unless the Rights are earlier redeemed, in the event that, after
the Distribution Date, (i) the Company is acquired in a merger or other
business combination transaction in which the Company is not the surviving 
corporation or in which the Company's outstanding Common Shares are changed 
or exchanged for stock or assets of another person or (ii) 50% or more of the 
Company's consolidated assets or earning power is sold (other than in 
transactions in the ordinary course of business), proper provision will be 
made so that each holder of a Right which has not theretofore been exercised 
(other than Rights beneficially owned by the Acquiring Person, which will 
thereafter be void) will thereafter have the right to receive, upon exercise, 
shares of common stock of the acquiring company having a value equal to 
two times the Purchase Price (unless the transaction satisfies certain 
conditions and is consummated with a person who acquired shares pursuant to 
a Permitted Offer, in which case the Rights will expire).

Exchange Provision

        At any time after the acquisition by an Acquiring Person of beneficial
ownership of 10% or more of the Company's outstanding Common Shares and prior
to the acquisition by such Acquiring Person of 50% or more of the Company's
outstanding Common Shares, the Board of Directors of the Company may exchange
the Rights (other than Rights owned by the Acquiring Person), in whole or in
part, at an exchange ratio of one Common Share per Right (subject to
adjustment).


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Adjustments to Prevent Dilution

        The Purchase Price payable, the number of Rights and the number of
Common Shares or other securities or property issuable upon exercise of the
Rights are subject to adjustment from time to time to prevent dilution as set
forth in the Amended Rights Agreement.  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.

Redemption

At any time on or prior to the close of business on the earlier of (i) ten
days (or such later date as may be determined by the Continuing Directors)
after the accumulation of beneficial ownership of 10% or more of the Company's
shares by a single acquiror or group or (ii) the Final Expiration Date of the
Rights, the Company may redeem the Rights in whole, but not in part, at a price
of $.01 per Right ("Redemption Price").  Immediately upon the action of the
Board of Directors ordering 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.

No Stockholders' Rights Prior to Exercise

Until a Right is exercised, the holder thereof, as such, will have no rights
as a stockholder of the Company (other than any rights resulting from such
holder's ownership of Common Shares), including, without limitation, the right
to vote or to receive dividends.

Amendment of Amended Rights Agreement

The provisions of the Amended Rights Agreement may be supplemented or amended
by the Board of Directors in any manner prior to the close of business on the
Distribution Date without the approval of Rights holders.  After the
Distribution Date, the provisions of the Amended Rights Agreement may be
amended by the Board in order to cure any ambiguity, defect or inconsistency,
to make changes which do not adversely affect the interests of holders of
Rights (excluding the interests of any Acquiring Person), or to shorten or
lengthen any time period under the Amended Rights Agreement; provided however,
that no amendment to adjust the time period governing redemption shall be made
at such time as the Rights are not redeemable.

Certain Anti-takeover Effects

        The Rights approved by the Board are designed to protect and maximize
the value of the outstanding equity interests in the Company in the event of an
unsolicited attempt by an acquiror to take over the Company in a manner or on
terms not approved by the Board of Directors.  Takeover attempts frequently
include coercive tactics to deprive a corporation's Board of Directors and its
stockholders of any real opportunity to determine the destiny of the
corporation. 

        The Rights have been declared by the Board in order to deter such
tactics, including a gradual accumulation of shares in the open market of a 10%
or greater position to be followed by a merger or a partial or two-tier tender
offer that does not treat all stockholders equally.  These tactics can unfairly
pressure stockholders, squeeze them out of their investment without giving them
any real choice and deprive them of the full value of their shares.

        The Rights are not intended to prevent a takeover of the Company on
appropriate terms and will not do so.  The Rights may be redeemed by the
Company at $.01 per Right within ten 


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days (or such later date as may be determined by the Continuing Directors) 
after the accumulation of beneficial ownership of 10% or more of the Company's 
shares by a single acquiror or group. Accordingly, the Rights should not 
interfere with any merger or business combination approved by the Board of 
Directors.

        Issuance of the Rights does not in any way weaken the financial strength
of the Company or interfere with its business plans. The issuance of the Rights
has no dilutive effect, will not affect reported earnings per share, should
not be taxable to the Company or to its stockholders and will not change the
way in which the Company's shares are presently traded.  The Company's Board
of Directors believes that the Rights represent a sound and reasonable means
of addressing the complex issues of corporate policy created by the current
takeover environment.

        However, the Rights may have the effect of rendering more difficult
or discouraging an acquisition of the Company in a manner deemed undesirable
by the Board of Directors.  The Rights may cause substantial dilution to a
person or group that attempts to acquire the Company on terms or in a manner
not approved by the Company's Board of Directors, except pursuant to an offer
conditioned upon the negation, purchase or redemption of the Rights.

Item 2.       Exhibits.

1.  First Amended and Restated Common Shares Rights Agreement dated as of
    December 14, 1990 between Sun Microsystems, Inc. and The First National 
    Bank of Boston, including the form of Rights Certificate and the 
    Summary of Terms attached thereto as Exhibits A and B, respectively.  
    Incorporated by reference to Amendment No. 1 to Registration Statement 
    on Form 8-A filed with the Securities and Exchange Commission by the 
    Company on December 24, 1990.

2.  Amendment dated as of October 28, 1991 to First Amended and Restated Common
    Shares Rights Agreement dated as of December 14, 1990 between Sun 
    Microsystems, Inc. and The First National Bank of Boston.  Incorporated by 
    reference to Amendment No. 2 to Registration Statement on Form 8-A filed 
    with the Securities and Exchange Commission by the Company on 
    November 6, 1991.

3.  Second Amendment dated as of August 5, 1992 to First Amended and Restated
    Common Shares Rights Agreement dated as of December 14, 1990 between Sun
    Microsystems, Inc. and The First National Bank of Boston.  Incorporated by
    reference to Amendment No. 3 to Registration Statement on Form 8-A filed 
    with the Securities and Exchange Commission by the Company on 
    September 16, 1992. 

4.  Third Amendment dated as of November 2, 1994 to First Amended and Restated
    Common Shares Rights Agreement dated as of December 14, 1990 between Sun
    Microsystems, Inc. and The First National Bank of Boston.


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                                  SIGNATURE

        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.

November 16, 1994                       SUN MICROSYSTEMS, INC.

                                        By: /s/  MICHAEL H. MORRIS
                                            ----------------------------------
                                            Michael H. Morris, Vice President,
                                            General Counsel and Secretary


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                                 EXHIBIT INDEX

Exhibit Number

   4.     Third Amendment dated as of November 2, 1994 to First Amended and
          Restated Common Shares Rights Agreement dated as of December 16, 1990 
          between Sun Microsystems, Inc. and The First National Bank of Boston.


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EX-4

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                                   EXHIBIT 4

                                THIRD AMENDMENT
                                       TO
                           FIRST AMENDED AND RESTATED
                         COMMON SHARES RIGHTS AGREEMENT

        Third Amendment dated as of November 2, 1994 (the "Amendment"), to the
First Amended and Restated Common Shares Rights Agreement dated as of December
14, 1990, as amended todate (the "Agreement"), between Sun Microsystems, Inc.,
a Delaware corporation (the "Company") and The First National Bank of Boston
(the "Rights Agent").

        WHEREAS, the Board of Directors of the Company has determined that
it is in the best interests of the Company and its stockholders to amend the
Agreement as set forth herein and the Rights Agent has agreed to such
amendment; and

        WHEREAS, the Company and the Rights Agent have determined that, pursuant
to Section 27 of the Agreement, the Agreement may be amended as set forth
herein without the approval of the holders of the Rights (as defined in the
Agreement).

        NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein set forth, the Agreement is hereby amended as follows:

        1.  Section 1(c)(i) of the Rights Agreement is hereby amended in its
entirety to read as follows:

       "(c)    A Person shall be deemed the "Beneficial Owner" of and shall be 
               deemed to "beneficially own" any securities:

               (i) which such Person or any of such Person's Affiliates or 
               Associates beneficially owns, directly or indirectly, for 
               purposes of Section 13(d) of the Exchange Act and Rule 13d-3 
               thereunder (or any comparable or successor law or regulation); 
               provided, however, if such Person or any of such Person's 
               Affiliates or Associates, as the case may be, files pursuant to 
               Rule 13d-1 of the Exchange Act a Schedule 13G and, therefore, is
               not required to file a Schedule 13D, reporting beneficial 
               ownership of not greater than twenty percent (20%) of the 
               Company's outstanding Common Shares, then such Person, or any of
               such Person's Affiliates or Associates, as the case may be, 
               shall not be deemed the "Beneficial Owner" and shall not be 
               considered to "beneficially own" any securities so held nor be 
               deemed an "Acquiring Person" for purposes of this Agreement, 
               but only for so long as such Person, or any of such Person's
               Affiliates or Associates, as the case may be, (i) does not 
               file, nor in the determination of the Board of Directors is 
               it required to file, a report on Schedule 13D pursuant to 
               Section 13(d) or  Rule 13d-1 of the Exchange Act, or (ii) 
               notwithstanding the foregoing proviso, beneficially owns 
               less than twenty percent (20%) of the Company's outstanding 
               Common Shares."