~~Table~~UNITED STATES SECURITIES ofAND ~~Contents~~EXCHANGE COMMISSION

~~UNITED~~WASHINGTON, ~~STATES SECURITIES~~DC ~~AND EXCHANGE COMMISSION~~ 20549

~~WASHINGTON, DC 20549~~ FORM 8-K

~~FORM~~CURRENT REPORT ~~8-K~~PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

~~CURRENT~~Date ~~REPORT~~of ~~PURSUANT~~report: ~~TO SECTION~~October 21, ~~13 OR 15~~2010 (d)Date OFof ~~THE SECURITIES~~earliest ~~EXCHANGE~~event ~~ACT OF 1934~~ reported)

~~Date of report: September 13~~ArcSight, ~~2010 (Date of earliest event reported)~~ Inc.

~~ArcSight,~~(Exact ~~Inc.~~ Name of Registrant as Specified in Its Charter)

Delaware (~~Exact~~State ~~Name~~or ofOther ~~Registrant~~Jurisdiction asof ~~Specified in Its Charter~~Incorporation)

Delaware (State or Other Jurisdiction of Incorporation)

001-33923		52-2241535
(Commission File Number)		(IRS Employer Identification No.)

001-33923		52-2241535
5 Results Way
(Commission File Number)		(IRS Employer Identification No.)
Cupertino, California		95014
(Address of Principal Executive Offices)		(Zip Code)

5 Results Way
Cupertino, California		95014
(Address of Principal Executive Offices)		(Zip Code)

(408) 864-2600
(Registrant’s Telephone Number, Including Area Code)

Check ~~(408)~~the appropriate box below if the Form ~~864~~8-~~2600~~K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the ~~(Registrant’s~~following ~~Telephone~~provisions ~~Number,~~(see ~~Including~~General Instruction ~~Area~~A.2. ~~Code~~below):

~~Check~~o Written ~~the~~communications ~~appropriate~~pursuant ~~box below if the Form 8-K filing is intended~~ to ~~simultaneously satisfy~~Rule 425 ~~the filing obligation of the registrant~~ under ~~any of~~ the ~~following~~Securities ~~provisions~~Act (~~see~~17 ~~General Instruction~~CFR A230.~~2. below~~425):

o Soliciting ~~Written~~material ~~communications~~ pursuant to Rule ~~425~~ 14a-12 under the ~~Securities~~Exchange Act (17 CFR ~~230~~240.~~425~~14a-12)

o Pre-commencement ~~Soliciting~~communications ~~material~~ pursuant to Rule ~~14a~~ 14d-12 2(b) under the Exchange Act (17 CFR 240.~~14a~~14d-122(b))

þ o Pre-commencement communications pursuant to Rule ~~14d~~ 13e-24(bc) under the Exchange Act (17 CFR 240.~~14d~~13e-24(bc))

oItem ~~Pre-commencement~~3.01 ~~communications~~Notice ~~pursuant~~of Delisting or Failure to ~~Rule~~Satisfy ~~13e-4(c)~~a ~~under~~Continued ~~the~~Listing ~~Exchange~~Rule ~~Act~~or ~~(17~~Standard; ~~CFR~~Transfer ~~240~~of Listing.~~13e-4(c))~~

~~TABLE~~As previously OFdisclosed, ~~CONTENTS~~on September 13, 2010, ArcSight, Inc. (the “Company”), Hewlett-Packard Company (“HP”) and Priam Acquisition Corporation, a wholly owned subsidiary of HP (“Purchaser”), entered into an Agreement and Plan of Merger (the “Merger Agreement”). Pursuant to the Merger Agreement, and upon the terms and subject to the conditions thereof, Purchaser agreed to purchase all outstanding shares of the Company’s common stock (the “Shares”) at a price of $43.50 per share, in cash to the seller (the “Offer Price”), without interest and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated September 22, 2010 (as amended or supplemented, the “Offer to Purchase”), and the related Letter of Transmittal (which, together with the Offer to Purchase, constitute the “Offer”).

~~Item~~Pursuant to ~~1.01.~~the ~~Entry~~terms and conditions of the Merger Agreement, Purchaser was merged with and into the Company (the “Merger”) on October 22, 2010 in accordance with the “short form” merger provisions available under Delaware law, which allow the completion of the Merger without a ~~Material~~vote ~~Definitive~~or ~~Agreement~~meeting ~~Item~~of 5stockholders of the Company.~~02.~~ ~~Departure~~On October 21, 2010, in connection with the Merger, the Company notified The NASDAQ Global Market (“NASDAQ”) of ~~Directors~~its orintent ~~Certain~~to ~~Officers;~~remove ~~Election~~its common stock from listing on NASDAQ and requested that NASDAQ file a delisting application with the Securities and Exchange Commission (“SEC”) to delist and deregister its common stock. On October 22, 2010, NASDAQ filed with the SEC a Notification of ~~Directors;~~Removal ~~Appointment~~from Listing and/or Registration under Section 12(b) of ~~Certain~~the ~~Officers;~~Securities ~~Compensatory~~Exchange ~~Arrangements~~Act of ~~Certain~~1934, ~~Officers~~as amended ~~Item~~(the ~~8.01.~~“Exchange ~~Other~~Act”), ~~Events~~on Form 25 ~~Item~~to 9delist and deregister the Company’s common stock.~~01.~~ ~~Financial~~The ~~Statements~~Company will file with the SEC a certification on Form 15 under the Exchange Act, requesting the deregistration of the Company’s common stock and ~~Exhibits~~the ~~SIGNATURES~~suspension of ~~EXHIBIT~~the ~~INDEX~~Company’s ~~EX-2.1~~reporting ~~EX-4.1~~obligations ~~EX-99~~under Sections 13 and 15(d) of the Exchange Act.1

~~Table~~Item 3.02 Unregistered Sales of ~~Contents~~Equity Securities.

~~Item~~In order to complete the Merger, on October 121, 2010, pursuant to Section 2.~~01.~~4 ~~Entry~~of ~~into~~the Merger Agreement, HP exercised its top-up option (the “Top-Up Option”) to purchase shares of the Company’s common stock, and accordingly, the Company issued 36,891,559 Shares (the “Top-Up Shares”) to Purchaser, at a ~~Material~~price ~~Definitive~~per ~~Agreement~~Share of $43.50. Purchaser paid for the Top-Up Shares by delivery of cash and a promissory note.

~~Merger~~The Company ~~Agreement~~offered and sold the Top-Up Shares as a private placement pursuant to an exemption from registration provided by Section 4(2) of the Securities Act of 1933, as amended (the “Securities Act”). The Company relied on the representations made by Purchaser that it was an “accredited investor” as defined in Rule 501 of Regulation D under the Securities Act and the fact that the offer and sale of the Top-Up Shares was a transaction by an issuer not involving a public offering.

OnItem ~~September 13, 2010, ArcSight, Inc~~3.03 ~~(“ArcSight”)~~Material ~~entered~~Modification ~~into an Agreement and Plan of Merger (the “Merger Agreement”) with Hewlett-Packard Company (“HP”) and Priam Acquisition Corporation, a wholly owned subsidiary of HP (“Purchaser”). Pursuant~~ to ~~the~~Rights ~~Merger Agreement, and upon the terms and subject to the conditions thereof, Purchaser will commence a cash tender offer (the “Tender Offer”) for all outstanding shares~~ of ~~ArcSight’s~~Security ~~common stock (the “Shares”) at a purchase price of $43~~Holders.50 per share, in cash to the seller without interest and less any required withholding taxes (the “Offer Price”). As soon as practicable following completion of the Tender Offer, including any subsequent offering period or the exercise of the “top-up option” described below, Purchaser will merge with and into ArcSight, and ArcSight will become a wholly owned subsidiary of HP (the “Merger”) as described in more detail below. In the Merger, the remaining stockholders of ArcSight, other than such stockholders who have validly exercised their appraisal rights under the Delaware General Corporation Law, would be entitled to receive the Offer Price.

At the effective time of the Merger ~~(the “Effective Time”)~~, ~~(1)~~ each ~~Company~~issued ~~stock~~and ~~option~~outstanding ~~that~~Share (other than (a1) isShares ~~outstanding~~held ~~and~~by ~~vested~~HP, asPurchaser ofor ~~immediately prior to~~ the ~~Effective~~Company, ~~Time~~or ~~(after~~by ~~giving~~any ~~effect~~direct toor ~~any~~indirect ~~acceleration~~wholly-owned insubsidiary ~~connection~~of ~~with~~HP, ~~the~~Purchaser ~~Effective~~or ~~Time)~~the ~~and~~Company, and (b2) ~~has~~Shares anowned ~~exercise~~by ~~price~~stockholders ~~per~~who ~~share that~~properly isexercise ~~less~~appraisal ~~than the Offer Price shall be cancelled and in exchange each former holder of any such~~rights ~~cancelled~~under ~~Company~~Delaware ~~stock~~law) ~~option~~was ~~shall~~converted beinto ~~paid~~the anright ~~amount in cash equal~~ to ~~the~~receive ~~product of (i)~~ the ~~excess~~ ~~of the~~ Offer Price, without ~~over~~interest ~~the~~and ~~exercise~~less ~~price~~any ~~per~~required ~~share~~withholding ~~under~~taxes. ~~such~~At ~~Company~~the ~~stock~~effective ~~option and~~time ~~(ii)~~ of the ~~number~~Merger, holders of ~~shares~~Shares ~~subject~~ceased to ~~such~~have ~~Company~~any ~~stock~~rights ~~option~~as ~~and~~holders ~~(2) each~~of ~~Company stock option~~Shares ~~that~~ (~~a) is~~other ~~outstanding~~than ~~and~~their ~~unvested~~right ~~as of immediately prior~~ to ~~the~~receive ~~Effective Time and (b) has an exercise price per share that is less than~~ the Offer Price, ~~shall~~without beinterest ~~assumed by HP~~ and ~~converted~~less ~~automatically~~any atrequired ~~the~~withholding ~~Effective~~taxes) ~~Time~~and ~~into~~accordingly anno ~~option~~longer tohave ~~purchase~~any ~~shares~~interest ofin the HPCompany’s ~~common~~future ~~stock (proportionally~~earnings ~~adjusted)~~or growth.

As a condition to consummating the Tender Offer, ArcSight stockholders must have validly tendered (and not withdrawn) outstanding Shares constituting at least a majority of the Shares (taking into account all Shares that ArcSight would be required to issue pursuant to the conversion or exercise of options, rights and securities that are then convertible into or exercisable for Shares). In addition, the obligation of Purchaser to consummate the Tender Offer is subject to several additional customary conditions described in the Merger Agreement, including, among others, the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the receipt of antitrust or merger control approvals under applicable laws of Germany and Austria. The consummation of the Tender Offer is not subject to a financing condition. 1

IfItem ~~more~~5.01 ~~than~~Changes ~~a majority of the outstanding Shares, but fewer than 90% of the outstanding Shares, are validly tendered (and not withdrawn)~~ in ~~the~~Control ~~Tender Offer, Purchaser shall be obligated to purchase the tendered Shares but may elect to conduct a subsequent offering period in order to achieve ownership~~ of ~~90% of the outstanding Shares, in order to effect a short-form~~ Registrant.

~~Table~~The Offer expired at 12:00 midnight, New York City time, on Wednesday, October 20. The depositary for the Offer advised HP and Purchaser that, as of ~~Contents~~such time, (i) including Shares tendered by notice of guaranteed delivery, an aggregate of approximately 33.1 million Shares were validly tendered into, and not withdrawn from, the Offer, representing approximately 92.1% of the outstanding Shares, and (ii) excluding Shares tendered by notice of guaranteed delivery, an aggregate of approximately 30.6 million Shares were validly tendered into, and not withdrawn from, the Offer, representing approximately 85.1% of the outstanding Shares. Purchaser has accepted for payment all Shares that were validly tendered and not withdrawn, and payment will be made promptly, in accordance with the terms of the Offer.

~~merger under~~Pursuant to the ~~Delaware~~terms ~~General~~and ~~Corporation~~conditions ~~Law.~~of Inthe ~~addition~~Merger Agreement, ~~subject~~Purchaser towas ~~certain~~merged ~~conditions~~with and ~~limitations~~into the Company on October 22, ~~ArcSight~~2010 ~~has~~in ~~granted~~accordance HPwith athe “~~top-up option~~short form” tomerger ~~purchase~~provisions ~~that~~available ~~number~~under ofDelaware law, which allow the ~~authorized~~completion ~~but~~of ~~unissued~~the ~~Shares~~Merger aswithout ~~would~~a ~~enable~~vote ~~Purchaser~~or ~~upon~~meeting ~~exercise~~of stockholders of ~~such~~the Company. In ~~top~~order to accomplish the Merger, on October 21, 2010, Purchaser exercised the Top-upUp ~~option~~Option, which permitted Purchaser to purchase ~~achieve~~the ~~ownership~~Top-Up ofShares. In ~~90%~~connection of with the ~~then~~Merger, each issued and outstanding Share (other than (1) Shares, ~~provided~~held by HP, ~~that~~Purchaser or the Company, inor noby ~~event~~any ~~shall~~direct or indirect wholly-owned subsidiary of HP, Purchaser or the Company, and (2) Shares owned by ~~top-up~~stockholders ~~option~~who beproperly ~~exercisable~~exercise ~~for~~appraisal arights ~~number~~under ofDelaware ~~such~~law) ~~authorized~~was converted ~~but~~into ~~unissued~~the ~~shares~~right into ~~excess~~receive the Offer Price, without interest and less any required withholding taxes. Following the consummation of the Merger, ~~total~~the ~~authorized~~Company ~~but~~continued ~~unissued~~as ~~Shares~~the surviving corporation and a wholly-owned subsidiary of HP.

~~Under~~In connection with the ~~terms~~Offer ofand ~~the~~ Merger ~~Agreement~~, ~~ArcSight~~HP ~~has~~and ~~agreed~~Purchaser ~~not to solicit or knowingly facilitate any alternative Acquisition Proposals (as defined in the Merger Agreement)~~paid, ~~subject to customary exceptions that permit ArcSight to respond to an Acquisition Proposal that ArcSight’s Board of Directors concludes~~ in ~~good faith constitutes or is reasonably likely to lead to a Superior Proposal (as defined in~~ the ~~Merger Agreement)~~aggregate, ~~provided, that, ArcSight’s Board of~~ ~~Directors~~approximately ~~has determined in good faith that the failure to do so would reasonably be expected to result in a breach of its fiduciary duties~~$1.7 ~~ArcSight~~billion ~~is also permitted to terminate the Merger Agreement~~ in ~~order~~cash ~~to accept a Superior Proposal~~consideration, ~~subject~~consisting ~~to giving HP three business days’ notice~~ of ~~its~~cash ~~intention~~on ~~to do so, but only if HP fails to make a binding counter-offer that ArcSight’s~~hand ~~Board of Directors determines in good faith, is at least as favorable to ArcSight stockholders as such Superior Proposal~~ and ~~ArcSight~~the ~~pays~~proceeds ~~HP a termination fee~~ of ~~$61 million.~~short Interm ~~addition, this termination fee is payable by ArcSight to HP under other specified circumstances~~borrowing.

~~The closing of the Merger is also subject to customary closing conditions. If Purchaser~~To ~~achieves ownership of 90% of~~ the ~~outstanding~~knowledge ~~Shares through the Tender Offer or the exercise~~ of the ~~top-up~~ ~~option described above~~Company, itexcept ~~may effect the Merger~~ as aset ~~short-form~~forth ~~merger~~herein, ~~without~~there aare ~~vote or~~no ~~any further action by ArcSight stockholders. Otherwise~~arrangements, HPincluding ~~and~~any ~~Purchaser~~pledge ~~will~~by ~~need~~any toperson ~~obtain the approval~~ of ~~ArcSight~~securities ~~stockholders holding a majority~~ of the ~~Shares to adopt the Merger Agreement~~Company ~~prior~~or toHP, ~~consummating~~ the ~~Merger.~~operation Inof ~~this~~which ~~event,~~may ~~ArcSight~~at ~~will call and convene~~ a ~~stockholder meeting~~subsequent todate ~~obtain~~result ~~this~~in ~~approval,~~a ~~and Purchaser will vote all Shares it acquires pursuant to the~~further ~~Tender~~change ~~Offer, subsequent offering period, if any, and the exercise of the top-up option, if any,~~ in ~~favor~~ ofcontrol ~~the adoption~~ of the ~~Merger Agreement, thereby assuring approval~~Company.

~~Tender~~Item ~~and~~5.02 ~~Stockholder~~Departure ~~Support~~of ~~Agreement~~ Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

~~In order~~ Pursuant to ~~induce~~the HPterms ~~and~~of ~~Purchaser to enter into~~ the Merger Agreement, ~~certain~~at ~~stockholders of ArcSight (in their capacities as stockholders of ArcSight) entered into Tender and Support Agreements (~~the ~~“Tender~~effective ~~Agreements”)~~time ~~with HP and Purchaser concurrently with the execution and delivery~~ of the Merger ~~Agreement.~~on October 22, ~~Subject to the terms and conditions of the Tender Agreements~~2010, ~~these~~ ~~stockholders agreed to~~ (1) ~~tender~~all of the ~~Shares~~directors ~~beneficially~~and ~~owned~~officers byof ~~them in~~ the ~~tender offer~~ ~~five~~Company ~~business~~immediately ~~days~~ prior to the ~~expiration~~effective time of the ~~tender~~Merger ~~offer~~resigned as directors and ~~not~~officers ~~withdraw~~of the ~~Shares,~~Company and (2) ~~vote~~ the ~~against~~directors ~~any~~and ~~actions or agreements, which would materially impede, delay or interfere with, or~~officers ~~prevent~~of orPurchaser ~~nullify,~~immediately ~~the~~prior ~~Merger. Pursuant~~ to ~~their terms,~~ the ~~Tender~~effective ~~Agreements~~time ~~will terminate upon the earlier~~ of ~~(a)~~ the ~~termination of the~~ Merger ~~Agreement~~became ~~in accordance with its terms, (b)~~ the ~~written~~directors ~~agreement~~and ofofficers ~~the parties to the Tender Agreements to terminate the Tender Agreements, (c) the consummation~~ of the ~~Merger and (d)~~ Company.

~~Table~~Item 5.03 Amendments to Articles of ~~Contents~~Incorporation or Bylaws; Change in Fiscal Year.

On October 22, 2010, in connection with the ~~date~~Merger, the Company’s certificate of incorporation was amended and ~~time~~restated (the “Amended Charter”) to be substantially in the form of Purchaser’s certificate of incorporation as ~~any~~in ~~amendment~~effect orimmediately ~~change~~prior to the effective time of the Merger. Also on October 22, 2010, in connection with the ~~Agreement~~Merger, orthe Bylaws of the ~~Tender~~Company ~~Offer~~(the ~~that~~“Amended ~~decreases~~Bylaws”) were amended and restated in substantially the ~~Offer~~form ~~Price~~of isPurchaser’s ~~effected~~bylaws as in effect immediately prior to the effective time of the Merger. The Amended Charter and the Amended Bylaws are attached hereto as Exhibits 3.1 and 3.2, respectively, and are incorporated herein by reference.

The foregoing descriptions of the Merger Agreement and the Tender Agreements are only summaries, do not purport to be complete and are qualified in their entirety by reference to the Merger Agreement and form of Tender Agreement, copies of which are filed as Exhibit 2.1 and Exhibit 4.1, respectively, hereto and are incorporated herein by reference. The representations, warranties and covenants contained in the Merger Agreement were made only for purposes of the Merger Agreement and as of specified dates, were solely for the benefit of the parties to the Merger Agreement, and may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures exchanged between the parties in connection with the execution of the Merger Agreement. The representations and warranties may have been made for the purposes of allocating contractual risk between the parties to the Merger Agreement instead of establishing these matters as facts, and may be subject to standards of materiality applicable to the contracting parties that differ from those applicable to investors. Investors should not rely on the representations, warranties and covenants or any descriptions thereof as characterizations of the actual state of facts or condition of HP, Purchaser, ArcSight or any of their respective subsidiaries or affiliates. Moreover, information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in ArcSight’s public disclosures.

Item 59.~~02.~~01 ~~Departure~~Financial ofStatements ~~Directors~~and ~~or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers~~Exhibits.

On September 12, 2010, ArcSight’s Compensation Committee approved, and ArcSight’s Board of Directors ratified, a change of control arrangement for Hugh Njemanze, ArcSight’s Founder, Chief Technology Officer and Executive Vice President of Research and Development. The arrangement provides that if Mr. Njemanze is terminated without cause or terminates his employment for good reason within 18 months after a change of control transaction, the vesting of Mr. Njemanze’s ArcSight stock options (~~the “Options”~~d) will be accelerated such that he will receive credit for an additional 24 months of vesting of the Options (beyond the amount vested as of such termination in accordance with their original vesting schedules); provided, that, this arrangement is only applicable to the transactions contemplated by the Merger Agreement. Exhibits

Item 8.01. Other Events.

Exhibit No.		Description
3.1		Amended Certificate of Incorporation of ArcSight, Inc.
3.2		Amended Bylaws of ArcSight, Inc.

~~On September 13, 2010, HP and ArcSight issued a joint press release relating to the Merger Agreement. A copy of the press release is attached hereto as Exhibit 99.1.~~ 3

~~Forward-Looking Statements~~ SIGNATURES

~~This~~Pursuant to ~~report~~the ~~contains~~requirements ~~projections~~of ~~and~~the ~~other~~Securities ~~forward-looking~~Exchange ~~statements~~Act ~~regarding~~of 1934, the ~~expected~~registrant has ~~performance~~duly ofcaused HPthis ~~following~~report ~~completion~~to ofbe ~~the~~signed ~~acquisition,~~on ~~including~~its ~~statements~~behalf ~~related~~by tothe ~~HP’s~~undersigned hereunto duly authorized.

	ARCSIGHT, INC.


Date: October 22, 2010	By:	/s/ Paul T. Porrini
		Paul T. Porrini
		Secretary

product and service offerings and the future of the enterprise threat and risk management market. Statements regarding future events are based on the parties’ current expectations and are necessarily subject to associated risks related to, among other things, obtaining a sufficient number of tendered shares of common stock and regulatory approval of the merger, the potential impact on the business of ArcSight due to the uncertainty about the acquisition, the retention of employees of ArcSight and the ability of HP to successfully integrate ArcSight and to achieve expected benefits. Actual results may differ materially from those in the projections or other forward-looking statements. For information regarding other related risks, please see the “Risk Factors” section of ArcSight’s filings with the United States Securities and Exchange Commission, including its most recent filings on Form 10-K and Form 10-Q.4

~~Securities Law Disclosures~~ EXHIBIT INDEX

This report is for informational purposes only and is not an offer to buy or the solicitation of an offer to sell any securities. The solicitation and the offer to buy shares of ArcSight common stock will be made only pursuant to an offer to purchase and related materials that HP intends to file with the United States Securities and Exchange Commission. ArcSight stockholders and other investors should read these materials carefully because they contain important information, including the terms and conditions of the offer. Once filed, copies of the tender offer statement on Schedule TO, the offer to purchase and related documents will be made available to ArcSight stockholders at no expense to them. In addition, those materials will be available without charge from ArcSight Investor Relations at (415) 293-4427 or by email at robert.dougherty@fd.com, or the United States Securities and Exchange Commission through the Commission’s website at www.sec.gov. ArcSight stockholders and other investors are urged to read carefully those materials prior to making any decisions with respect to the offer.

Exhibit No.		Description
3.1		Amended Certificate of Incorporation of ArcSight, Inc.
3.2		Amended Bylaws of ArcSight, Inc.

~~Item 9.01. Financial Statements and Exhibits.~~ 5

(d) Exhibits.

Number		Description
2.1		Agreement and Plan of Merger, dated as of September 13, 2010, among HP, Purchaser and ArcSight.
4.1		Form of Tender and Support Agreement, among HP, Purchaser and certain stockholders of ArcSight.
99.1		Joint Press Release by HP and ArcSight, dated September 13, 2010.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

ArcSight, Inc. By: /s/ Stewart Grierson Stewart Grierson Chief Financial Officer

Date: September 13, 2010

EXHIBIT INDEX

Number		Description
2.1		Agreement and Plan of Merger, dated as of September 13, 2010, among HP, Purchaser and ArcSight.
4.1		Form of Tender and Support Agreement, among HP, Purchaser and certain stockholders of ArcSight.
99.1		Joint Press Release by HP and ArcSight, dated September 13, 2010.

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