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                                                                   EXHIBIT 10.28

                          ARGONAUT TECHNOLOGIES, INC.

                            1995 INCENTIVE STOCK PLAN

                            (AS AMENDED AND RESTATED)

        1. Purposes of the Plan. The purposes of this Stock Plan are to attract
and retain the best available personnel for positions of substantial
responsibility, to provide additional incentive to Employees and Consultants of
the Company and its Subsidiaries and to promote the success of the Company's
business. Options granted under the Plan may be incentive stock options (as
defined under Section 422 of the Code) or non-statutory stock options, as
determined by the Administrator at the time of grant of an option and subject to
the applicable provisions of Section 422 of the Code, as amended, and the
regulations promulgated thereunder. Stock purchase rights may also be granted
under the Plan.

        2. Definitions. As used herein, the following definitions shall apply:

                (a) "Administrator" means the Board or any of its Committees
appointed pursuant to Section 4 of the Plan.

                (b) "Board" means the Board of Directors of the Company.

                (c) "Cause" means the (i) Employee's engagement in acts of
embezzlement, dishonesty or moral turpitude; (ii) the conviction of Employee for
having committed a felony; (iii) a breach by Employee of Employee's fiduciary
duties and responsibilities to the Company having the potential to result in an
adverse effect on the Company's business, operations, prospects or reputation;
(iv) gross negligence or bad faith as determined by a duly authorized
representative of the Company; or (v) the repeated failure of Employee to
perform Employee's duties and responsibilities to the reasonable satisfaction of
a duly authorized representative of the Company except in the case of death or
disability.

                (d) "Change of Control" means the occurrence of any of the
following events:

                        (i) Any "person" (as such term is used in Sections 13(d)
and 14(d) of the Exchange Act) becomes the "beneficial owner" (as defined in
Rule 13d-3 of the Exchange Act), directly or indirectly, of securities of the
Company representing fifty percent (50%) or more of the total voting power
represented by the Company's then outstanding voting securities; or

                        (ii) The consummation of the sale or disposition by the
Company of all or substantially all of the Company's assets; or

                        (iii) The consummation of a merger or consolidation of
the Company with any other corporation, other than a merger or consolidation
which would result in the voting securities of the Company outstanding
immediately prior thereto continuing to represent (either by remaining
outstanding or by being converted into voting securities of the surviving entity
or its parent) at least fifty percent (50%) of the total voting power
represented by the voting securities of

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the Company or such surviving entity or its parent outstanding immediately after
such merger or consolidation.

                (e) "Code" means the Internal Revenue Code of 1986, as amended.

                (f) "Committee" means a Committee appointed by the Board of
Directors in accordance with Section 4 of the Plan.

                (g) "Common Stock" means the Common Stock of the Company.

                (h) "Company" means Argonaut Technologies, Inc., a Delaware
corporation.

                (i) Constructive Termination. "Constructive Termination" shall
mean the Employee voluntarily resigns within ninety (90) days after the
occurrence of any of the following (i) without the Employee's express written
consent, a material reduction of the Employee's duties, title, authority or
responsibilities, relative to the Employee's duties, title, authority or
responsibilities as in effect immediately prior to such reduction, or the
assignment to Employee of such reduced duties, title, authority or
responsibilities; provided, however, that a reduction in duties, title,
authority or responsibilities solely by virtue of the Company being acquired and
made part of a larger entity (as, for example, when the Chief Executive Officer
of the Company remains as such following a Change of Control and is not made the
Chief Executive Officer of the acquiring corporation) shall not by itself
constitute grounds for a "Constructive Termination" (ii) without the Employee's
express written consent, a material reduction, without good business reasons, of
the facilities and perquisites (including office space and location) available
to the Employee immediately prior to such reduction; (iii) a more than ten
percent (10%) reduction by the Company of the base salary of the Employee as in
effect immediately prior to such reduction; (iv) a material reduction by the
Company in the kind or level of employee benefits, including bonuses, to which
the Employee was entitled immediately prior to such reduction with the result
that the Employee's overall benefits package is materially reduced; (v) the
relocation of the Employee to a facility or a location outside of a one-hundred
(100) mile radius from the Employee's present location or facility, without the
Employee's express written consent; (vi) the failure of the Company to obtain
the assumption of this agreement by any successors contemplated in Article X
below; or (vii) any act or set of facts or circumstances which would, under
California case law or statute constitute a constructive termination of the
Employee.

                (j) "Consultant" means any person who is engaged by the Company
or any Parent or Subsidiary to render consulting or advisory services and is
compensated for such services, and any director of the Company whether
compensated for such services or not, provided that if and in the event the
Company registers any class of any equity security pursuant to the Exchange Act,
the term Consultant shall thereafter not include directors who are not
compensated for their services or are paid only a director's fee by the Company.

                (k) "Continuous Status as an Employee or Consultant" means that
the employment or consulting relationship with the Company or any Parent or
Subsidiary is not interrupted or terminated. Continuous Status as an Employee or
Consultant shall not be considered interrupted in the case of: (i) any leave of
absence approved by the Company, including sick leave, military leave, or any
other personal leave; provided, however, that for purposes of Incentive Stock

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Options, no such leave may exceed ninety (90) days, unless reemployment upon the
expiration of such leave is guaranteed by contract (including certain Company
policies) or statute; provided, further, that on the ninety-first (91st) day of
any such leave (where reemployment is not guaranteed by contract or statute) the
Optionee's Incentive Stock Option shall cease to be treated as an Incentive
Stock Option and will be treated for tax purposes as a Nonstatutory Stock
Option; or (ii) transfers between locations of the Company or between the
Company, its Parent, its Subsidiaries or its successor.

                (l) "Employee" means any person, including officers and
directors, employed by the Company or any Parent or Subsidiary of the Company.
The payment of a director's fee by the Company shall not be sufficient to
constitute "employment" by the Company.

                (m) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                (n) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                        (i) If the Common Stock is listed on any established
stock exchange or a national market system, including without limitation the
Nasdaq National Market of the National Association of Securities Dealers, Inc.
Automated Quotation ("NASDAQ") System, its Fair Market Value shall be the
closing sales price for such stock (or the closing bid, if no sales were
reported, as quoted on such exchange or system for the last market trading day
prior to the time of determination) as reported in The Wall Street Journal or
such other source as the Administrator deems reliable;

                        (ii) If the Common Stock is quoted on the NASDAQ System
(but not on the Nasdaq National Market thereof) or regularly quoted by a
recognized securities dealer but selling prices are not reported, its Fair
Market Value shall be the mean between the high bid and low asked prices for the
Common Stock on the last market trading day prior to the day of determination,
or;

                        (iii) In the absence of an established market for the
Common Stock, the Fair Market Value thereof shall be determined in good faith by
the Administrator in accordance with Section 260.140.40, Title 10 of the
California Code of Regulations ("California Code").

                (o) "Incentive Stock Option" means an Option intended to qualify
as an incentive stock option within the meaning of Section 422 of the Code.

                (p) "Nonstatutory Stock Option" means an Option not intended to
qualify as an Incentive Stock Option.

                (q) "Officer" means a person who is an officer of the Company
within the meaning of Section 16 of the Exchange Act and the rules and
regulations promulgated thereunder.

                (r) "Option" means a stock option granted pursuant to the Plan.

                (s) "Optioned Stock" means the Common Stock subject to an Option
or a Stock Purchase Right.

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                (t) "Optionee" means an Employee or Consultant who receives an
Option or Stock Purchase Right.

                (u) "Parent" means a "parent corporation", whether now or
hereafter existing, as defined in Section 424(e) of the Code.

                (v) "Plan" means this 1995 Incentive Stock Plan.

                (w) "Restricted Stock" means shares of Common Stock acquired
pursuant to a grant of a Stock Purchase Right under Section 11 below.

                (x) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 12 below.

                (y) "Stock Purchase Right" means the right to purchase Common
Stock pursuant to Section 11 below.

                (z) "Subsidiary" means a "subsidiary corporation", whether now
or hereafter existing, as defined in Section 424(f) of the Code.

        3. Stock Subject to the Plan. Subject to the provisions of Section 12 of
the Plan, the maximum aggregate number of shares which may be optioned and sold
under the Plan is 3,935,308 shares of Common Stock. The shares may be
authorized, but unissued, or reacquired Common Stock.

                If an Option or Stock Purchase Right should expire or become
unexercisable for any reason without having been exercised in full, the
unpurchased Shares which were subject thereto shall, unless the Plan shall have
been terminated, become available for future grant under the Plan.

        4. Administration of the Plan.

                (a) Initial Plan Procedure. Prior to the date, if any, upon
which the Company becomes subject to the Exchange Act, the Plan shall be
administered by the Board or a committee appointed by the Board.

                (b) Plan Procedure After the Date, if any, upon Which the
Company becomes Subject to the Exchange Act.

                        (i) Administration With Respect to Directors and
Officers. With respect to grants of Options or Stock Purchase Rights to
Employees who are also officers or directors of the Company, the Plan shall be
administered by (A) the Board if the Board may administer the Plan in compliance
with Rule 16b-3 promulgated under the Exchange Act or any successor thereto
("Rule 16b-3") with respect to a plan intended to qualify thereunder as a
discretionary plan, or (B) a committee designated by the Board to administer the
Plan, which committee shall be constituted in such a manner as to permit the
Plan to comply with Rule 16b-3 with respect to a plan intended to qualify
thereunder as a discretionary plan. Once appointed, such Committee shall
continue to serve in its designated capacity until otherwise directed by the
Board. From time to time the Board may

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increase the size of the Committee and appoint additional members thereof,
remove members (with or without cause) and appoint new members in substitution
therefor, fill vacancies, however caused, and remove all members of the
Committee and thereafter directly administer the Plan, all to the extent
permitted by Rule 16b-3 with respect to a plan intended to qualify thereunder as
a discretionary plan.

                        (ii) Multiple Administrative Bodies. If permitted by
Rule 16b-3, the Plan may be administered by different bodies with respect to
directors, non-director officers and Employees who are neither directors nor
officers.

                        (iii) Administration With Respect to Consultants and
Other Employees. With respect to grants of Options or Stock Purchase Rights to
Employees or Consultants who are neither directors nor officers of the Company,
the Plan shall be administered by (A) the Board or (B) a committee designated by
the Board, which committee shall be constituted in such a manner as to satisfy
the legal requirements relating to the administration of incentive stock option
plans, if any, of California corporate and securities laws, of the Code, and of
any applicable stock exchange (the "Applicable Laws"). Once appointed, such
Committee shall continue to serve in its designated capacity until otherwise
directed by the Board. From time to time the Board may increase the size of the
Committee and appoint additional members thereof, remove members (with or
without cause) and appoint new members in substitution therefor, fill vacancies,
however caused, and remove all members of the Committee and thereafter directly
administer the Plan, all to the extent permitted by the Applicable Laws.

                (c) Powers of the Administrator. Subject to the provisions of
the Plan and, in the case of a Committee, the specific duties delegated by the
Board to such Committee, and subject to the approval of any relevant
authorities, including the approval, if required, of any stock exchange upon
which the Common Stock is listed, the Administrator shall have the authority, in
its discretion:

                        (i) to determine the Fair Market Value of the Common
Stock, in accordance with Section 2(k) of the Plan;

                        (ii) to select the Consultants and Employees to whom
Options and Stock Purchase Rights may from time to time be granted hereunder;

                        (iii) to determine whether and to what extent Options
and Stock Purchase Rights or any combination thereof are granted hereunder;

                        (iv) to determine the number of shares of Common Stock
to be covered by each such award granted hereunder;

                        (v)to approve forms of agreement for use under the Plan;

                        (vi) to determine the terms and conditions, not
inconsistent with the terms of the Plan, of any award granted hereunder;

                        (vii) to determine whether and under what circumstances
an Option may be settled in cash under subSection 9(f) instead of Common Stock;

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                        (viii) to reduce the exercise price of any Option to the
then current Fair Market Value if the Fair Market Value of the Common Stock
covered by such Option shall have declined since the date the Option was
granted;

                        (ix) to determine the terms and restrictions applicable
to Stock Purchase Rights and the Restricted Stock purchased by exercising such
Stock Purchase Rights; and

                        (x) to construe and interpret the terms of the Plan and
awards granted pursuant to the Plan.

                (d) Effect of Administrator's Decision. All decisions,
determinations and interpretations of the Administrator shall be final and
binding on all Optionees and any other holders of any Options or Stock Purchase
Rights.

        5. Eligibility.

                (a) Nonstatutory Stock Options and Stock Purchase Rights may be
granted to Employees and Consultants. Incentive Stock Options may be granted
only to Employees. An Employee or Consultant who has been granted an Option or
Stock Purchase Right may, if otherwise eligible, be granted additional Options
or Stock Purchase Rights.

                (b) Each Option shall be designated in the written option
agreement as either an Incentive Stock Option or a Nonstatutory Stock Option.
However, notwithstanding such designations, to the extent that the aggregate
Fair Market Value:

                        (i) of Shares subject to an Optionee's Incentive Stock
Options granted by the Company, any Parent or Subsidiary, which

                        (ii) become exercisable for the first time during any
calendar year (under all plans of the Company or any Parent or Subsidiary)
exceeds $100,000, such excess Options shall be treated as Nonstatutory Stock
Options. For purposes of this Section 5(b), Incentive Stock Options shall be
taken into account in the order in which they were granted, and the Fair Market
Value of the Shares shall be determined as of the time the Option with respect
to such Shares is granted.

                (c) The Plan shall not confer upon any Optionee any right with
respect to continuation of employment relationship with the Company, nor shall
it interfere in any way with his or her right or the Company's right to
terminate his or her employment relationship at any time, with or without cause.

                (d) Upon the Company or a successor corporation issuing any
class of common equity securities required to be registered under Section 12 of
the Exchange Act or upon the Plan being assumed by a corporation having a class
of common equity securities required to be registered under Section 12 of the
Exchange Act, the following limitations shall apply to grants of Options and
Stock Purchase Rights to Employees:

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                        (i) The foregoing limitation shall be adjusted
proportionately in connection with any change in the Company's capitalization as
described in Section 12(a).

                        (ii) If an Option or Stock Purchase Right is cancelled
(other than in connection with a transaction described in Section 12), the
cancelled Option or Stock Purchase Right will be counted against the limit set
forth in Section 5(e)(i). For this purpose, if the exercise price of an Option
or Stock Purchase Right is reduced, the transaction will be treated as a
cancellation of the Option or Stock Purchase Right and the grant of a new Option
or Stock Purchase Right.

        6. Term of Plan. The Plan shall become effective upon the earlier to
occur of its adoption by the Board of Directors or its approval by the
shareholders of the Company, as described in Section 18 of the Plan. It shall
continue in effect for a term of ten (10) years unless sooner terminated under
Section 14 of the Plan.

        7. Term of Option. The term of each Option shall be the term stated in
the Option Agreement; provided, however, that the term shall be no more than ten
(10) years from the date of grant thereof. However, in the case of an Incentive
Stock Option granted to an Optionee who, at the time the Option is granted, owns
stock representing more than ten percent (10%) of the voting power of all
classes of stock of the Company or any Parent or Subsidiary, the term of the
Option shall be five (5) years from the date of grant thereof or such shorter
term as may be provided in the Option Agreement.

        8. Option Exercise Price and Consideration.

                (a) The per share exercise price for the Shares to be issued
pursuant to exercise of an Option shall be such price as is determined by the
Board, but shall be subject to the following:

                        (i) In the case of an Incentive Stock Option

                                (A) granted to an Employee who, at the time of
the grant of such Incentive Stock Option, owns stock representing more than ten
percent (10%) of the voting power of all classes of stock of the Company or any
Parent or Subsidiary, the per Share exercise price shall be no less than 110% of
the Fair Market Value per Share on the date of grant.

                                (B) granted to any Employee other than an
Employee described in the preceding paragraph, the per Share exercise price
shall be no less than 100% of the Fair Market Value per Share on the date of
grant.

                        (ii) In the case of a Nonstatutory Stock Option

                                (A) granted to a person who, at the time of the
grant of such Option, owns stock representing more than ten percent (10%) of the
voting power of all classes of stock of the Company or any Parent or Subsidiary,
the per Share exercise price shall be no less than 110% of the Fair Market Value
per Share on the date of the grant.

                                (B) granted to any person, the per Share
exercise price shall be no less than 85% of the Fair Market Value per Share on
the date of grant.

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                (b) The consideration to be paid for the Shares to be issued
upon exercise of an Option, including the method of payment, shall be determined
by the Administrator (and, in the case of an Incentive Stock Option, shall be
determined at the time of grant) and may consist entirely of (1) cash, (2)
check, (3) promissory note, (4) other Shares which (x) in the case of Shares
acquired upon exercise of an Option, have been owned by the Optionee for more
than six months on the date of surrender, and (y) have a Fair Market Value on
the date of surrender equal to the aggregate exercise price of the Shares as to
which said Option shall be exercised, (5) delivery of a properly executed
exercise notice together with such other documentation as the Administrator and
the broker, if applicable, shall require to effect an exercise of the Option and
delivery to the Company of the sale or loan proceeds required to pay the
exercise price, or (6) any combination of the foregoing methods of payment. In
making its determination as to the type of consideration to accept, the Board
shall consider if acceptance of such consideration may be reasonably expected to
benefit the Company.

        9. Exercise of Option.

                (a) Procedure for Exercise; Rights as a Shareholder. Any Option
granted hereunder shall be exercisable at such times and under such conditions
as determined by the Board, including performance criteria with respect to the
Company and/or the Optionee, and as shall be permissible under the terms of the
Plan. In no event shall the Option be exercised at a rate of less than 20% per
year over five years from the date of grant of the Option.

                        An Option may not be exercised for a fraction of a
Share.

                        An Option shall be deemed to be exercised when written
notice of such exercise has been given to the Company in accordance with the
terms of the Option by the person entitled to exercise the Option and full
payment for the Shares with respect to which the Option is exercised has been
received by the Company. Full payment may, as authorized by the Board, consist
of any consideration and method of payment allowable under Section 8(b) of the
Plan. Until the issuance (as evidenced by the appropriate entry on the books of
the Company or of a duly authorized transfer agent of the Company) of the stock
certificate evidencing such Shares, no right to vote or receive dividends or any
other rights as a shareholder shall exist with respect to the Optioned Stock,
notwithstanding the exercise of the Option. The Company shall issue (or cause to
be issued) such stock certificate promptly upon exercise of the Option. No
adjustment will be made for a dividend or other right for which the record date
is prior to the date the stock certificate is issued, except as provided in
Section 12 of the Plan.

                        Exercise of an Option in any manner shall result in a
decrease in the number of Shares which thereafter may be available, both for
purposes of the Plan and for sale under the Option, by the number of Shares as
to which the Option is exercised.

                (b) Termination of Employment or Consulting Relationship. In the
event of termination of an Optionee's Continuous Status as an Employee or
Consultant with the Company (but not in the event of an Optionee's change of
status from Employee to Consultant (in which case an Employee's Incentive Stock
Option shall automatically convert to a Nonstatutory Stock Option on the
ninety-first (91st) day following such change of status) or from Consultant to
Employee), such

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Optionee may, but only within such period of time as is determined by the
Administrator, of at least thirty (30) days, with such determination in the case
of an Incentive Stock Option not exceeding three (3) months after the date of
such termination (but in no event later than the expiration date of the term of
such Option as set forth in the Option Agreement), exercise his or her Option to
the extent that Optionee was entitled to exercise it at the date of such
termination. To the extent that Optionee was not entitled to exercise the Option
at the date of such termination, or if Optionee does not exercise such Option to
the extent so entitled within the time specified herein, the Option shall
terminate.

                (c) Disability of Optionee. In the event of termination of an
Optionee's consulting relationship or Continuous Status as an Employee as a
result of his or her disability, Optionee may, but only within six (6) months
from the date of such termination (and in no event later than the expiration
date of the term of such Option as set forth in the Option Agreement), exercise
the Option to the extent otherwise entitled to exercise it at the date of such
termination; provided, however, that if such disability is not a "disability" as
such term is defined in Section 22(e)(3) of the Code, in the case of an
Incentive Stock Option such Incentive Stock Option shall automatically convert
to a Nonstatutory Stock Option on the day three months and one day following
such termination. To the extent that Optionee was not entitled to exercise the
Option at the date of termination, or if Optionee does not exercise such Option
to the extent so entitled within the time specified herein, the Option shall
terminate, and the Shares covered by such Option shall revert to the Plan.

                (d) Death of Optionee. In the event of the death of an Optionee,
the Option may be exercised at any time within twelve (12) months following the
date of death (but in no event later than the expiration of the term of such
Option as set forth in the Notice of Grant), by the Optionee's estate or by a
person who acquired the right to exercise the Option by bequest or inheritance,
but only to the extent that the Optionee was entitled to exercise the Option at
the date of death. If, at the time of death, the Optionee was not entitled to
exercise his or her entire Option, the Shares covered by the unexercisable
portion of the Option shall immediately revert to the Plan. If, after death, the
Optionee's estate or a person who acquired the right to exercise the Option by
bequest or inheritance does not exercise the Option within the time specified
herein, the Option shall terminate, and the Shares covered by such Option shall
revert to the Plan.

                (e) Rule 16b-3. Options granted to persons subject to Section
16(b) of the Exchange Act must comply with Rule 16b-3 and shall contain such
additional conditions or restrictions as may be required thereunder to qualify
for the maximum exemption from Section 16 of the Exchange Act with respect to
Plan transactions.

                (f) Buyout Provisions. The Administrator may at any time offer
to buy out for a payment in cash or Shares, an Option previously granted, based
on such terms and conditions as the Administrator shall establish and
communicate to the Optionee at the time that such offer is made.

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        10. Non-Transferability of Options and Stock Purchase Rights. Options
and Stock Purchase Rights may not be sold, pledged, assigned, hypothecated,
transferred, or disposed of in any manner other than by will or by the laws of
descent or distribution and may be exercised, during the lifetime of the
Optionee, only by the Optionee.

        11. Stock Purchase Rights.

                (a) Rights to Purchase. Stock Purchase Rights may be issued
either alone, in addition to, or in tandem with other awards granted under the
Plan and/or cash awards made outside of the Plan. After the Administrator
determines that it will offer Stock Purchase Rights under the Plan, it shall
advise the offeree in writing of the terms, conditions and restrictions related
to the offer, including the number of Shares that such person shall be entitled
to purchase, the price to be paid, and the time within which such person must
accept such offer, which shall in no event exceed thirty (30) days from the date
upon which the Administrator made the determination to grant the Stock Purchase
Right. The offer shall be accepted by execution of a Restricted Stock purchase
agreement in the form determined by the Administrator. Shares purchased pursuant
to the grant of a Stock Purchase Right shall be referred to herein as
"Restricted Stock."

                (b) Repurchase Option. Unless the Administrator determines
otherwise, the Restricted Stock purchase agreement shall grant the Company a
repurchase option exercisable within 90 days of the voluntary or involuntary
termination of the purchaser's employment with the Company for any reason
(including death or Disability). The purchase price for Shares repurchased
pursuant to the Restricted Stock purchase agreement shall be the original price
paid by the purchaser and may be paid by cancellation of any indebtedness of the
purchaser to the Company. The repurchase option shall lapse at such rate as the
Administrator may determine, but at a minimum rate of 20% per year.

                (c) Other Provisions. The Restricted Stock purchase agreement
shall contain such other terms, provisions and conditions not inconsistent with
the Plan as may be determined by the Administrator in its sole discretion. In
addition, the provisions of Restricted Stock purchase agreements need not be the
same with respect to each purchaser.

                (d) Rights as a Shareholder. Once the Stock Purchase Right is
exercised, the purchaser shall have the rights equivalent to those of a
shareholder, and shall be a shareholder when his or her purchase is entered upon
the records of the duly authorized transfer agent of the Company. No adjustment
will be made for a dividend or other right for which the record date is prior to
the date the Stock Purchase Right is exercised, except as provided in Section 12
of the Plan.

        12. Adjustments Upon Changes in Capitalization or Merger.

                (a) Changes in Capitalization. Subject to any required action by
the shareholders of the Company, the number of shares of Common Stock covered by
each outstanding Option or Stock Purchase Right, and the number of shares of
Common Stock which have been authorized for issuance under the Plan but as to
which no Options or Stock Purchase Rights have yet been granted or which have
been returned to the Plan upon cancellation or expiration of an Option or Stock
Purchase Right, as well as the price per share of Common Stock covered by each
such outstanding

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Option or Stock Purchase Right, shall be proportionately adjusted for any
increase or decrease in the number of issued shares of Common Stock resulting
from a stock split, reverse stock split, stock dividend, combination or
reclassification of the Common Stock, or any other increase or decrease in the
number of issued shares of Common Stock effected without receipt of
consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration." Such adjustment shall be made by the Board,
whose determination in that respect shall be final, binding and conclusive.
Except as expressly provided herein, no issuance by the Company of shares of
stock of any class, or securities convertible into shares of stock of any class,
shall affect, and no adjustment by reason thereof shall be made with respect to,
the number or price of shares of Common Stock subject to an Option or Stock
Purchase Right.

                (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Board shall notify the Optionee
at least fifteen (15) days prior to such proposed action. To the extent it has
not been previously exercised, the Option or Stock Purchase Right will terminate
immediately prior to the consummation of such proposed action.

                (c) Merger. Subject to subsection (d) below, in the event of a
merger of the Company with or into another corporation, the Option or Stock
Purchase Right shall be assumed or an equivalent option or right shall be
substituted by such successor corporation or a parent or subsidiary of such
successor corporation. If, in such event, the Option or Stock Purchase Right is
not assumed or substituted, the Option or Stock Purchase Right shall terminate
as of the date of the closing of the merger. For the purposes of this paragraph,
the Option or Stock Purchase Right shall be considered assumed if, following the
merger, the option or right confers the right to purchase, for each Share of
Optioned Stock subject to the Option or Stock Purchase Right immediately prior
to the merger, the consideration (whether stock, cash, or other securities or
property) received in the merger by holders of Common Stock for each Share held
on the effective date of the transaction (and if holders were offered a choice
of consideration, the type of consideration chosen by the holders of a majority
of the outstanding Shares); provided, however, that if such consideration
received in the merger was not solely common stock of the successor corporation
or its Parent, the Administrator may, with the consent of the successor
corporation, provide for the consideration to be received upon the exercise of
the Option or Stock Purchase Right, for each Share of Optioned Stock subject to
the Option or Stock Purchase Right, to be solely common stock of the successor
corporation or its Parent equal in fair market value to the per share
consideration received by holders of Common Stock in the merger.

                (d) Change of Control. In the event of (a) A Constructive
Termination or (b) Optionee's termination by the Company without Cause, within
twelve (12) months following a Change of Control, all outstanding options shall
become fully vested and exercisable.

                                      -11-
<PAGE>   12

        13. Time of Granting Options and Stock Purchase Rights. The date of
grant of an Option or Stock Purchase Right shall, for all purposes, be the date
on which the Administrator makes the determination granting such Option or Stock
Purchase Right, or such other date as is determined by the Board. Notice of the
determination shall be given to each Employee or Consultant to whom an Option or
Stock Purchase Right is so granted within a reasonable time after the date of
such grant.

        14. Amendment and Termination of the Plan.

                (a) Amendment and Termination. The Board may at any time amend,
alter, suspend or discontinue the Plan, but no amendment, alteration, suspension
or discontinuation shall be made which would impair the rights of any Optionee
under any grant theretofore made, without his or her consent. In addition, to
the extent necessary and desirable to comply with Rule 16b-3 under the Exchange
Act or with Section 422 of the Code (or any other applicable law or regulation,
including the requirements of the NASD or an established stock exchange), the
Company shall obtain shareholder approval of any Plan amendment in such a manner
and to such a degree as required.

                (b) Effect of Amendment or Termination. Any such amendment or
termination of the Plan shall not affect Options or Stock Purchase Rights
already granted, and such Options and Stock Purchase Rights shall remain in full
force and effect as if this Plan had not been amended or terminated, unless
mutually agreed otherwise between the Optionee and the Board, which agreement
must be in writing and signed by the Optionee and the Company.

        15. Conditions Upon Issuance of Shares. Shares shall not be issued
pursuant to the exercise of an Option or Stock Purchase Right unless the
exercise of such Option or Stock Purchase Right and the issuance and delivery of
such Shares pursuant thereto shall comply with all relevant provisions of law,
including, without limitation, the Securities Act of 1933, as amended, the
Exchange Act, the rules and regulations promulgated thereunder, and the
requirements of any stock exchange upon which the Shares may then be listed, and
shall be further subject to the approval of counsel for the Company with respect
to such compliance.

                As a condition to the exercise of an Option or Stock Purchase
Right, the Company may require the person exercising such Option or Stock
Purchase Right to represent and warrant at the time of any such exercise that
the Shares are being purchased only for investment and without any present
intention to sell or distribute such Shares if, in the opinion of counsel for
the Company, such a representation is required by any of the aforementioned
relevant provisions of law.

        16. Reservation of Shares. The Company, during the term of this Plan,
will at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

                The inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company's
counsel to be necessary to the lawful issuance and sale of any Shares hereunder,
shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained.

                                      -12-
<PAGE>   13

        17. Agreements. Options and Stock Purchase Rights shall be evidenced by
written agreements in such form as the Board shall approve from time to time.

        18. Shareholder Approval. Continuance of the Plan shall be subject to
approval by the shareholders of the Company within twelve (12) months before or
after the date the Plan is adopted. Such shareholder approval shall be obtained
in the degree and manner required under applicable state and federal law and the
rules of any stock exchange upon which the Common Stock is listed.

        19. Information to Optionees and Purchasers. The Company shall provide
to each Optionee and to each individual who acquired Shares pursuant to the
Plan, not less frequently than annually during the period such Optionee or
purchaser has one or more Options or Stock Purchase Rights outstanding, and, in
the case of an individual who acquired Shares pursuant to the Plan, during the
period such individual owns such Shares, copies of annual financial statements.
The Company shall not be required to provide such statements to key employees
whose duties in connection with the Company assure their access to equivalent
information.

                                      -13-<PAGE>   1

                               CRITICAL PATH, INC.

                             1999 STOCK OPTION PLAN

        1. Purposes of the Plan. The purposes of this Nonstatutory Stock Option
Plan are:

        - to attract and retain the best available personnel for positions of
          substantial responsibility,

        - to provide additional incentive to Employees, Directors and
          Consultants, and

        - to promote the success of the Company's business.

        Options granted under the Plan will be Nonstatutory Stock Options.

        2. Definitions. As used herein, the following definitions shall apply:

                (a) "Administrator" means the Board or any of its Committees as
shall be administering the Plan, in accordance with Section 4 of the Plan.

                (b) "Applicable Laws" means the requirements relating to the
administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of
any foreign country or jurisdiction where Options are, or will be, granted under
the Plan.

                (c) "Board" means the Board of Directors of the Company.

                (d) "Code" means the Internal Revenue Code of 1986, as amended.

                (e) "Committee" means a committee of Directors appointed by the
Board in accordance with Section 4 of the Plan.

                (f) "Common Stock" means the Common Stock of the Company.

                (g) "Company" means Critical Path, Inc., a California
corporation.

                (h) "Consultant" means any person, including an advisor, engaged
by the Company or a Parent or Subsidiary to render services to such entity.

                (i) "Director" means a member of the Board.

<PAGE>   2

                (j) "Disability" means total and permanent disability as defined
in Section 22(e)(3) of the Code.

                (k) "Employee" means any person, including Officers, employed by
the Company or any Parent or Subsidiary of the Company. A Service Provider shall
not cease to be an Employee in the case of (i) any leave of absence approved by
the Company or (ii) transfers between locations of the Company or between the
Company, its Parent, any Subsidiary, or any successor. Neither service as a
Director nor payment of a director's fee by the Company shall be sufficient to
constitute "employment" by the Company.

                (l) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                (m) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                        (i) If the Common Stock is listed on any established
stock exchange or a national market system, including without limitation the
Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market,
its Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
The Wall Street Journal or such other source as the Administrator deems
reliable;

                        (ii) If the Common Stock is regularly quoted by a
recognized securities dealer but selling prices are not reported, the Fair
Market Value of a Share of Common Stock shall be the mean between the high bid
and low asked prices for the Common Stock on the last market trading day prior
to the day of determination, as reported in The Wall Street Journal or such
other source as the Administrator deems reliable;

                        (iii) In the absence of an established market for the
Common Stock, the Fair Market Value shall be determined in good faith by the
Administrator.

                (n) "Notice of Grant" means a written or electronic notice
evidencing certain terms and conditions of an individual Option grant. The
Notice of Grant is part of the Option Agreement.

                (o) "Officer" means a person who is an officer of the Company
within the meaning of Section 16 of the Exchange Act and the rules and
regulations promulgated thereunder.

                (p) "Option" means a nonstatutory stock option granted pursuant
to the Plan, that is not intended to qualify as an incentive stock option within
the meaning of Section 422 of the Code and the regulations promulgated
thereunder.

                (q) "Option Agreement" means an agreement between the Company
and an Optionee evidencing the terms and conditions of an individual Option
grant. The Option Agreement is subject to the terms and conditions of the Plan.

                                      -2-
<PAGE>   3

                (r) "Option Exchange Program" means a program whereby
outstanding options are surrendered in exchange for options with a lower
exercise price.

                (s) "Optioned Stock" means the Common Stock subject to an
Option.

                (t) "Optionee" means the holder of an outstanding Option granted
under the Plan.

                (u) "Parent" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

                (v) "Plan" means this 1999 Stock Option Plan.

                (w) "Service Provider" means an Employee including an Officer,
Consultant or Director.

                (x) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 12 of the Plan.

                (y) "Subsidiary" means a "subsidiary corporation," whether now
or hereafter existing, as defined in Section 424(f) of the Code.

        3. Stock Subject to the Plan. Subject to the provisions of Section 12 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 4,000,000 Shares. The Shares may be authorized, but unissued,
or reacquired Common Stock.

        If an Option expires or becomes unexercisable without having been
exercised in full, or is surrendered pursuant to an Option Exchange Program, the
unpurchased Shares which were subject thereto shall become available for future
grant or sale under the Plan (unless the Plan has terminated).

        4. Administration of the Plan.

                (a) Administration. The Plan shall be administered by (i) the
Board or (ii) a Committee, which committee shall be constituted to satisfy
Applicable Laws.

                (b) Powers of the Administrator. Subject to the provisions of
the Plan, and in the case of a Committee, subject to the specific duties
delegated by the Board to such Committee, the Administrator shall have the
authority, in its discretion:

                        (i) to determine the Fair Market Value of the Common
Stock;

                        (ii) to select the Service Providers to whom Options may
be granted hereunder;

                        (iii) to determine whether and to what extent Options
are granted hereunder;

                                      -3-
<PAGE>   4

                        (iv) to determine the number of shares of Common Stock
to be covered by each Option granted hereunder;

                        (v) to approve forms of agreement for use under the
Plan;

                        (vi) to determine the terms and conditions, not
inconsistent with the terms of the Plan, of any award granted hereunder. Such
terms and conditions include, but are not limited to, the exercise price, the
time or times when Options may be exercised (which may be based on performance
criteria), any vesting acceleration or waiver of forfeiture restrictions, and
any restriction or limitation regarding any Option or the shares of Common Stock
relating thereto, based in each case on such factors as the Administrator, in
its sole discretion, shall determine;

                        (vii) to reduce the exercise price of any Option to the
then current Fair Market Value if the Fair Market Value of the Common Stock
covered by such Option shall have declined since the date the Option was
granted;

                        (viii) to institute an Option Exchange Program;

                        (ix) to construe and interpret the terms of the Plan and
awards granted pursuant to the Plan;

                        (x) to prescribe, amend and rescind rules and
regulations relating to the Plan, including rules and regulations relating to
sub-plans established for the purpose of qualifying for preferred tax treatment
under foreign tax laws;

                        (xi) to modify or amend each Option (subject to Section
14(b) of the Plan), including the discretionary authority to extend the
post-termination exercisability period of Options longer than is otherwise
provided for in the Plan;

                        (xii) to authorize any person to execute on behalf of
the Company any instrument required to effect the grant of an Option previously
granted by the Administrator;

                        (xiii) to determine the terms and restrictions
applicable to Options; and

                        (xiv) to make all other determinations deemed necessary
or advisable for administering the Plan.

                (c) Effect of Administrator's Decision. The Administrator's
decisions, determinations and interpretations shall be final and binding on all
Optionees and any other holders of Options.

        5. Eligibility. Options may be granted to Service Providers except
Officers and Directors; provided, however, that Options may be granted to
Officers in connection with the Officer's initial employment by the Company.

        6. Limitation. Neither the Plan nor any Option shall confer upon an
Optionee any right with respect to continuing the Optionee's relationship as a
Service Provider with the Company, nor

                                      -4-
<PAGE>   5

shall they interfere in any way with the Optionee's right or the Company's right
to terminate such relationship at any time, with or without cause.

        7. Term of Plan. The Plan shall become effective upon its adoption by
the Board. It shall continue in effect for ten (10) years, unless sooner
terminated under Section 14 of the Plan.

        8. Term of Option. The term of each Option shall be stated in the Option
Agreement.

        9. Option Exercise Price and Consideration.

                (a) Exercise Price. The per share exercise price for the Shares
to be issued pursuant to exercise of an Option shall be determined by the
Administrator.

                (b) Waiting Period and Exercise Dates. At the time an Option is
granted, the Administrator shall fix the period within which the Option may be
exercised and shall determine any conditions which must be satisfied before the
Option may be exercised.

                (c) Form of Consideration. The Administrator shall determine the
acceptable form of consideration for exercising an Option, including the method
of payment. Such consideration may consist entirely of:

                        (i) cash;

                        (ii) check;

                        (iii) promissory note;

                        (iv) other Shares which (A) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six months on the date of surrender, and (B) have a Fair Market Value on
the date of surrender equal to the aggregate exercise price of the Shares as to
which said Option shall be exercised;

                        (v) consideration received by the Company under a
cashless exercise program implemented by the Company in connection with the
Plan;

                        (vi) a reduction in the amount of any Company liability
to the Optionee, including any liability attributable to the Optionee's
participation in any Company-sponsored deferred compensation program or
arrangement;

                        (vii) such other consideration and method of payment for
the issuance of Shares to the extent permitted by Applicable Laws; or

                        (viii) any combination of the foregoing methods of
payment.

        10. Exercise of Option.

                                      -5-
<PAGE>   6

                (a) Procedure for Exercise; Rights as a Shareholder. Any Option
granted hereunder shall be exercisable according to the terms of the Plan and at
such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement. An Option may not be exercised for a fraction of
a Share.

                An Option shall be deemed exercised when the Company receives:
(i) written or electronic notice of exercise (in accordance with the Option
Agreement) from the person entitled to exercise the Option, and (ii) full
payment for the Shares with respect to which the Option is exercised. Full
payment may consist of any consideration and method of payment authorized by the
Administrator and permitted by the Option Agreement and the Plan. Shares issued
upon exercise of an Option shall be issued in the name of the Optionee or, if
requested by the Optionee, in the name of the Optionee and his or her spouse.
Until the Shares are issued (as evidenced by the appropriate entry on the books
of the Company or of a duly authorized transfer agent of the Company), no right
to vote or receive dividends or any other rights as a shareholder shall exist
with respect to the Optioned Stock, notwithstanding the exercise of the Option.
The Company shall issue (or cause to be issued) such Shares promptly after the
Option is exercised. No adjustment will be made for a dividend or other right
for which the record date is prior to the date the Shares are issued, except as
provided in Section 12 of the Plan.

                Exercising an Option in any manner shall decrease the number of
Shares thereafter available, both for purposes of the Plan and for sale under
the Option, by the number of Shares as to which the Option is exercised.

                (b) Termination of Relationship as a Service Provider. If an
Optionee ceases to be a Service Provider, other than upon the Optionee's death
or Disability, the Optionee may exercise his or her Option, but only within such
period of time as is specified in the Option Agreement, and only to the extent
that the Option is vested on the date of termination (but in no event later than
the expiration of the term of such Option as set forth in the Option Agreement).
In the absence of a specified time in the Option Agreement, the Option shall
remain exercisable for three (3) months following the Optionee's termination.
If, on the date of termination, the Optionee is not vested as to his or her
entire Option, the Shares covered by the unvested portion of the Option shall
revert to the Plan. If, after termination, the Optionee does not exercise his or
her Option within the time specified by the Administrator, the Option shall
terminate, and the Shares covered by such Option shall revert to the Plan.

                (c) Disability of Optionee. If an Optionee ceases to be a
Service Provider as a result of the Optionee's Disability, the Optionee may
exercise his or her Option within such period of time as is specified in the
Option Agreement, to the extent the Option is vested on the date of termination
(but in no event later than the expiration of the term of such Option as set
forth in the Option Agreement). In the absence of a specified time in the Option
Agreement, the Option shall remain exercisable for twelve (12) months following
the Optionee's termination. If, on the date of termination, the Optionee is not
vested as to his or her entire Option, the Shares covered by the unvested
portion of the Option shall revert to the Plan. If, after termination, the
Optionee does not exercise his or her Option within the time specified herein,
the Option shall terminate, and the Shares covered by such Option shall revert
to the Plan.

                                      -6-
<PAGE>   7

                (d) Death of Optionee. If an Optionee dies while a Service
Provider, the Option may be exercised within such period of time as is specified
in the Option Agreement (but in no event later than the expiration of the term
of such Option as set forth in the Notice of Grant), by the Optionee's estate or
by a person who acquires the right to exercise the Option by bequest or
inheritance, but only to the extent that the Option is vested on the date of
death. In the absence of a specified time in the Option Agreement, the Option
shall remain exercisable for twelve (12) months following the Optionee's
termination. If, at the time of death, the Optionee is not vested as to his or
her entire Option, the Shares covered by the unvested portion of the Option
shall immediately revert to the Plan. The Option may be exercised by the
executor or administrator of the Optionee's estate or, if none, by the person(s)
entitled to exercise the Option under the Optionee's will or the laws of descent
or distribution. If the Option is not so exercised within the time specified
herein, the Option shall terminate, and the Shares covered by such Option shall
revert to the Plan.

                (e) Buyout Provisions. The Administrator may at any time offer
to buy out for a payment in cash or Shares, an Option previously granted based
on such terms and conditions as the Administrator shall establish and
communicate to the Optionee at the time that such offer is made.

        11. Non-Transferability of Options. Unless determined otherwise by the
Administrator, an Option may not be sold, pledged, assigned, hypothecated,
transferred, or disposed of in any manner other than by will or by the laws of
descent or distribution and may be exercised, during the lifetime of the
Optionee, only by the Optionee. If the Administrator makes an Option
transferable, such Option shall contain such additional terms and conditions as
the Administrator deems appropriate.

        12. Adjustments Upon Changes in Capitalization, Dissolution, Merger or
Asset Sale.

                (a) Changes in Capitalization. Subject to any required action by
the shareholders of the Company, the number of shares of Common Stock covered by
each outstanding Option, and the number of shares of Common Stock which have
been authorized for issuance under the Plan but as to which no Options have yet
been granted or which have been returned to the Plan upon cancellation or
expiration of an Option, as well as the price per share of Common Stock covered
by each such outstanding Option, shall be proportionately adjusted for any
increase or decrease in the number of issued shares of Common Stock resulting
from a stock split, reverse stock split, stock dividend, combination or
reclassification of the Common Stock, or any other increase or decrease in the
number of issued shares of Common Stock effected without receipt of
consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration." Such adjustment shall be made by the Board,
whose determination in that respect shall be final, binding and conclusive.
Except as expressly provided herein, no issuance by the Company of shares of
stock of any class, or securities convertible into shares of stock of any class,
shall affect, and no adjustment by reason thereof shall be made with respect to,
the number or price of shares of Common Stock subject to an Option.

                (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Administrator shall notify each
Optionee as soon as practicable prior to the effective date of such proposed
transaction. The Administrator in its discretion may provide

                                      -7-
<PAGE>   8

for an Optionee to have the right to exercise his or her Option until ten (10)
days prior to such transaction as to all of the Optioned Stock covered thereby,
including Shares as to which the Option would not otherwise be exercisable. In
addition, the Administrator may provide that any Company repurchase option
applicable to any Shares purchased upon exercise of an Option shall lapse as to
all such Shares, provided the proposed dissolution or liquidation takes place at
the time and in the manner contemplated. To the extent it has not been
previously exercised, an Option will terminate immediately prior to the
consummation of such proposed action.

                (c) Merger or Asset Sale. In the event of a merger of the
Company with or into another corporation, or the sale of substantially all of
the assets of the Company, each outstanding Option shall be assumed or an
equivalent option or right substituted by the successor corporation or a Parent
or Subsidiary of the successor corporation. In the event that the successor
corporation refuses to assume or substitute for the Option, the Optionee shall
fully vest in and have the right to exercise the Option as to all of the
Optioned Stock, including Shares as to which it would not otherwise be vested or
exercisable. If an Option becomes fully vested and exercisable in lieu of
assumption or substitution in the event of a merger or sale of assets, the
Administrator shall notify the Optionee in writing or electronically that the
Option shall be fully vested and exercisable for a period of fifteen (15) days
from the date of such notice, and the Option shall terminate upon the expiration
of such period. For the purposes of this paragraph, the Option shall be
considered assumed if, following the merger or sale of assets, the option or
right confers the right to purchase or receive, for each Share of Optioned
Stock, immediately prior to the merger or sale of assets, the consideration
(whether stock, cash, or other securities or property) received in the merger or
sale of assets by holders of Common Stock for each Share held on the effective
date of the transaction (and if holders were offered a choice of consideration,
the type of consideration chosen by the holders of a majority of the outstanding
Shares); provided, however, that if such consideration received in the merger or
sale of assets is not solely common stock of the successor corporation or its
Parent, the Administrator may, with the consent of the successor corporation,
provide for the consideration to be received upon the exercise of the Option,
for each Share of Optioned Stock to be solely common stock of the successor
corporation or its Parent equal in fair market value to the per share
consideration received by holders of Common Stock in the merger or sale of
assets.

        13. Date of Grant. The date of grant of an Option shall be, for all
purposes, the date on which the Administrator makes the determination granting
such Option, or such other later date as is determined by the Administrator.
Notice of the determination shall be provided to each Optionee within a
reasonable time after the date of such grant.

        14. Amendment and Termination of the Plan.

                (a) Amendment and Termination. The Board may at any time amend,
alter, suspend or terminate the Plan.

                (b) Effect of Amendment or Termination. No amendment,
alteration, suspension or termination of the Plan shall impair the rights of any
Optionee, unless mutually agreed otherwise between the Optionee and the
Administrator, which agreement must be in writing and signed by the Optionee and
the Company. Termination of the Plan shall not affect the Administrator's
ability to

                                      -8-
<PAGE>   9

exercise the powers granted to it hereunder with respect to options granted
under the Plan prior to the date of such termination.

        15. Conditions Upon Issuance of Shares.

                (a) Legal Compliance. Shares shall not be issued pursuant to the
exercise of an Option unless the exercise of such Option and the issuance and
delivery of such Shares shall comply with Applicable Laws and shall be further
subject to the approval of counsel for the Company with respect to such
compliance.

                (b) Investment Representations. As a condition to the exercise
of an Option the Company may require the person exercising such Option to
represent and warrant at the time of any such exercise that the Shares are being
purchased only for investment and without any present intention to sell or
distribute such Shares if, in the opinion of counsel for the Company, such a
representation is required.

        16. Inability to Obtain Authority. The inability of the Company to
obtain authority from any regulatory body having jurisdiction, which authority
is deemed by the Company's counsel to be necessary to the lawful issuance and
sale of any Shares hereunder, shall relieve the Company of any liability in
respect of the failure to issue or sell such Shares as to which such requisite
authority shall not have been obtained.

        17. Reservation of Shares. The Company, during the term of this Plan,
will at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

                                      -9-
<PAGE>   10

                               CRITICAL PATH, INC.

                             1999 STOCK OPTION PLAN

                             STOCK OPTION AGREEMENT

        Unless otherwise defined herein, the terms defined in the Plan shall
have the same defined meanings in this Option Agreement.

I. NOTICE OF STOCK OPTION GRANT

        [OPTIONEE'S NAME AND ADDRESS]

        You have been granted an option to purchase Common Stock of the Company,
subject to the terms and conditions of the Plan and this Option Agreement, as
follows:

        Grant Number
                                             --------------------------

        Date of Grant
                                             --------------------------

        Vesting Commencement Date
                                             --------------------------

        Exercise Price per Share            $
                                             --------------------------

        Total Number of Shares Granted
                                             --------------------------

        Total Exercise Price                $
                                             --------------------------

        Type of Option:                      Nonstatutory Stock Option
                                             --------------------------

        Term/Expiration Date:
                                             --------------------------

        Vesting Schedule:
                                             --------------------------

        Subject to the Optionee continuing to be a Service Provider on such
dates, this Option shall vest and become exercisable in accordance with the
following schedule:

        [25% OF THE SHARES SUBJECT TO THE OPTION SHALL VEST TWELVE MONTHS AFTER
THE VESTING COMMENCEMENT DATE, AND 1/48TH OF THE SHARES SUBJECT TO THE OPTION
SHALL VEST UPON THE LAST DAY OF EACH MONTH THEREAFTER.]

<PAGE>   11

        Termination Period:

        This Option may be exercised for 30 days after Optionee ceases to be a
Service Provider. Upon the death or Disability of the Optionee, this Option may
be exercised for 6 months following the date of death or Disability of the
Optionee. In no event shall this Option be exercised later than the
Term/Expiration Date as provided above.

II. AGREEMENT

        1. Grant of Option. The Plan Administrator of the Company hereby grants
to the Optionee named in the Notice of Grant attached as Part I of this
Agreement (the "Optionee") an option (the "Option") to purchase the number of
Shares, as set forth in the Notice of Grant, at the exercise price per share set
forth in the Notice of Grant (the "Exercise Price"), subject to the terms and
conditions of the Plan, which is incorporated herein by reference. In the event
of a conflict between the terms and conditions of the Plan and the terms and
conditions of this Option Agreement, the terms and conditions of the Plan shall
prevail.

        2. Exercise of Option.

                (a) Right to Exercise. This Option is exercisable during its
term in accordance with the Vesting Schedule set out in the Notice of Grant and
the applicable provisions of the Plan and this Option Agreement.

                (b) Method of Exercise. This Option is exercisable by delivery
of an exercise notice, in the form attached as Exhibit A (the "Exercise
Notice"), which shall state the election to exercise the Option, the number of
Shares in respect of which the Option is being exercised (the "Exercised
Shares"), and such other representations and agreements as may be required by
the Company pursuant to the provisions of the Plan. The Exercise Notice shall be
completed by the Optionee and delivered to the Manager of Stock Compliance and
Equity Compensation. The Exercise Notice shall be accompanied by payment of the
aggregate Exercise Price as to all Exercised Shares. This Option shall be deemed
to be exercised upon receipt by the Company of such fully executed Exercise
Notice accompanied by such aggregate Exercise Price.

                No Shares shall be issued pursuant to the exercise of this
Option unless such issuance and exercise complies with Applicable Laws. Assuming
such compliance, for income tax purposes the Exercised Shares shall be
considered transferred to the Optionee on the date the Option is exercised with
respect to such Exercised Shares.

        3. Lock-Up Period. Optionee hereby agrees that, if so requested by the
Company or any representative of the underwriters (the "Managing Underwriter")
in connection with any registration of the offering of any securities of the
Company under the Securities Act, Optionee shall not sell or otherwise transfer
any Shares or other securities of the Company during the 180-day period (or such
other period as may be requested in writing by the Managing Underwriter and
agreed to in writing by the Company) (the "Market Standoff Period") following
the effective date of the Company's initial public offering. The Company may
impose stop-transfer instructions with respect to securities subject to the
foregoing restrictions until the end of such Market Standoff Period.

                                      -2-
<PAGE>   12

        4. Method of Payment. Payment of the aggregate Exercise Price shall be
by any of the following, or a combination thereof, at the election of the
Optionee:

                (a) cash;

                (b) check;

                (c) consideration received by the Company under a cashless
exercise program implemented by the Company in connection with the Plan; or

                (d) surrender of other Shares which (i) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six (6) months on the date of surrender, AND (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares.

        5. Non-Transferability of Option. This Option may not be transferred in
any manner otherwise than by will or by the laws of descent or distribution and
may be exercised during the lifetime of Optionee only by the Optionee. The terms
of the Plan and this Option Agreement shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.

        6. Term of Option. This Option may be exercised only within the term set
out in the Notice of Grant, and may be exercised during such term only in
accordance with the Plan and the terms of this Option Agreement.

        7. Tax Consequences. Some of the federal tax consequences relating to
this Option, as of the date of this Option, are set forth below. THIS SUMMARY IS
NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE.
THE OPTIONEE SHOULD CONSULT A TAX ADVISOR BEFORE EXERCISING THIS OPTION OR
DISPOSING OF THE SHARES.

                (a) Exercising the Option. The Optionee may incur regular
federal income tax liability upon exercise of an NSO. The Optionee will be
treated as having received compensation income (taxable at ordinary income tax
rates) equal to the excess, if any, of the Fair Market Value of the Exercised
Shares on the date of exercise over their aggregate Exercise Price. If the
Optionee is an Employee or a former Employee, the Company will be required to
withhold from his or her compensation or collect from Optionee and pay to the
applicable taxing authorities an amount in cash equal to a percentage of this
compensation income at the time of exercise, and may refuse to honor the
exercise and refuse to deliver Shares if such withholding amounts are not
delivered at the time of exercise.

                (b) Disposition of Shares. If the Optionee holds NSO Shares for
at least one year, any gain realized on disposition of the Shares will be
treated as long-term capital gain for federal income tax purposes.

        8. Entire Agreement; Governing Law. The Plan is incorporated herein by
reference. The Plan and this Option Agreement constitute the entire agreement of
the parties with respect to the subject matter hereof and supersede in their
entirety all prior undertakings and agreements of the

                                      -3-
<PAGE>   13

Company and Optionee with respect to the subject matter hereof, and may not be
modified adversely to the Optionee's interest except by means of a writing
signed by the Company and Optionee. This agreement is governed by the internal
substantive laws, but not the choice of law rules, of California.

        9. NO GUARANTEE OF CONTINUED SERVICE. OPTIONEE ACKNOWLEDGES AND AGREES
THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED
ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (AND NOT
THROUGH THE ACT OF BEING HIRED, BEING GRANTED AN OPTION OR PURCHASING SHARES
HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE
TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO
NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A
SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL
NOT INTERFERE WITH OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO TERMINATE
OPTIONEE'S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT
CAUSE.

        By your signature and the signature of the Company's representative
below, you and the Company agree that this Option is granted under and governed
by the terms and conditions of the Plan and this Option Agreement. Optionee has
reviewed the Plan and this Option Agreement in their entirety, has had an
opportunity to obtain the advice of counsel prior to executing this Option
Agreement and fully understands all provisions of the Plan and Option Agreement.
Optionee hereby agrees to accept as binding, conclusive and final all decisions
or interpretations of the Administrator upon any questions relating to the Plan
and Option Agreement. Optionee further agrees to notify the Company upon any
change in the residence address indicated below.

OPTIONEE                                    CRITICAL PATH, INC.

-----------------------------------         ------------------------------------
Signature                                   By

-----------------------------------         ------------------------------------
Print Name                                  Title

-----------------------------------
Residence Address

-----------------------------------

                                      -4-
<PAGE>   14

                                    EXHIBIT A

                               CRITICAL PATH, INC.

                             1999 STOCK OPTION PLAN

                                 EXERCISE NOTICE

        Critical Path, Inc.
        320 First Street
        San Francisco, CA  94105

        Attention: Manager, Stock Compliance and Equity Compensation

        1. Exercise of Option. Effective as of today, ________________, _____,
the undersigned ("Purchaser") hereby elects to purchase ______________ shares
(the "Shares") of the Common Stock of Critical Path, Inc. (the "Company") under
and pursuant to the 1999 Nonstatutory Stock Option Plan (the "Plan") and the
Stock Option Agreement dated ______, ___ , Grant Number _______ (the "Option
Agreement"). The purchase price for the Shares shall be $_______, as required by
the Option Agreement.

        2. Delivery of Payment. Purchaser herewith delivers to the Company the
full purchase price for the Shares.

        3. Representations of Purchaser. Purchaser acknowledges that Purchaser
has received, read and understood the Plan and the Option Agreement and agrees
to abide by and be bound by their terms and conditions.

        4. Rights as Shareholder. Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the Shares, no right to vote or receive dividends or
any other rights as a shareholder shall exist with respect to the Optioned
Stock, notwithstanding the exercise of the Option. The Shares so acquired shall
be issued to the Optionee as soon as practicable after exercise of the Option.
No adjustment will be made for a dividend or other right for which the record
date is prior to the date of issuance, except as provided in Section 12 of the
Plan.

        5. Tax Consultation. Purchaser understands that Purchaser may suffer
adverse tax consequences as a result of Purchaser's purchase or disposition of
the Shares. Purchaser represents that Purchaser has consulted with any tax
consultants Purchaser deems advisable in connection with

<PAGE>   15

the purchase or disposition of the Shares and that Purchaser is not relying on
the Company for any tax advice.

        6. Entire Agreement; Governing Law. The Plan and Option Agreement are
incorporated herein by reference. This Agreement, the Plan and the Option
Agreement constitute the entire agreement of the parties with respect to the
subject matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and Purchaser with respect to the subject matter
hereof, and may not be modified adversely to the Purchaser's interest except by
means of a writing signed by the Company and Purchaser. This agreement is
governed by the internal substantive laws, but not the choice of law rules, of
California.

Submitted by:                               Accepted by:

PURCHASER                                   CRITICAL PATH, INC.

-----------------------------------         ------------------------------------
Signature                                   By

-----------------------------------         ------------------------------------
Print Name                                  Title

                                            ------------------------------------
                                            Date Received

Address:                                    Address:   320 First Street
        ---------------------------
                                                       San Francisco, CA  94105

        ---------------------------

        ---------------------------

                                      -2-

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