Form of Confirmation for Capped Call Transactions

April [__], 2020

Re: [Base] [Additional] Call Option Transaction

The purpose of this letter agreement (this “Confirmation”) is to confirm the terms and conditions of the call option transaction entered into between [_________] (“Dealer”) and Slack Technologies, Inc. (“Counterparty”) as of the Trade Date specified below (the “Transaction”). This letter agreement constitutes a “Confirmation” as referred to in the ISDA Master Agreement specified below. Each party further agrees that this Confirmation together with the Agreement evidence a complete binding agreement between Counterparty and Dealer as to the subject matter and terms of the Transaction to which this Confirmation relates, and shall supersede all prior or contemporaneous written or oral communications with respect thereto.

The definitions and provisions contained in the 2002 ISDA Equity Derivatives Definitions (the “Equity Definitions”), as published by the International Swaps and Derivatives Association, Inc. (“ISDA”) are incorporated into this Confirmation. In the event of any inconsistency between the Equity Definitions and this Confirmation, this Confirmation shall govern. Certain defined terms used herein are based on terms that are defined in the Preliminary Offering Memorandum dated April [__], 2020 (the “Offering Memorandum”) relating to the [___]% Convertible Senior Notes due 2025 (the “Convertible Notes” and each USD 1,000 principal amount of Convertible Notes, a “Convertible Note”) as originally issued by Counterparty pursuant to the Purchase Agreement (as defined herein) and pursuant to an Indenture [to be] dated April [__], 2020 (the “Indenture”). In the event of any inconsistency between the terms defined in the Offering Memorandum, the Indenture and this Confirmation, this Confirmation shall govern. The parties acknowledge that this Confirmation is entered into on the date hereof with the understanding that (i) definitions set forth in the Indenture which are also defined herein by reference to the Indenture and (ii) sections of the Indenture that are referred to herein will conform to the descriptions thereof in the Offering Memorandum. If any such definitions in the Indenture or any such sections of the Indenture differ from the descriptions thereof in the Offering Memorandum, the descriptions thereof in the Offering Memorandum will govern for purposes of this Confirmation. The parties further acknowledge that the Indenture section numbers used herein are based on the [draft of the Indenture last reviewed by Dealer and the Counterparty as of the date of this Confirmation, and if any such section numbers are changed in the Indenture as executed, the parties will amend this Confirmation in good faith to preserve the intent of the parties][Indenture as executed]. Subject to the foregoing, references to the Indenture herein are references to the Indenture in effect on the date of its execution, and if the Indenture is amended or supplemented following such date (other than any amendment or supplement (x) pursuant to Section [10.01(h)] of the Indenture that, as determined by the Calculation Agent, conforms the Indenture to the description of Convertible Notes in the Offering Memorandum or (y) pursuant to Section [14.07(a)] of the Indenture, subject, in the case of this clause (y), to the second paragraph under “Method of Adjustment” in Section ‎3), any such amendment or supplement will be disregarded for purposes of this Confirmation (other than as provided in Section ‎9(h)(iv) below) unless the parties agree otherwise in writing. For purposes of the Equity Definitions, the Transaction shall be deemed to be a Share Option Transaction.

Each party is hereby advised, and each such party acknowledges, that the other party has engaged in, or refrained from engaging in, substantial financial transactions and has taken other material actions in reliance upon the parties’ entry into the Transaction to which this Confirmation relates on the terms and conditions set forth below.

1.This Confirmation evidences a complete and binding agreement between Dealer and Counterparty as to the terms of the Transaction to which this Confirmation relates. This Confirmation shall supplement, form a part of, and be subject to an agreement in the form of the 2002 ISDA Master Agreement (the “Agreement”) as if Dealer and Counterparty had executed an agreement in such form on the Trade Date but without any Schedule except for:

(a) the election of the laws of the State of New York as the governing law (without reference to choice of law doctrine) and the election of USD as the Termination Currency;

(b) (i) the election that the “Cross Default” provisions of Section 5(a)(vi) of the Agreement shall apply to Dealer with a “Threshold Amount” of three percent of shareholders’ equity of [Dealer] [[_________] (“Dealer Parent”)]; provided that “Specified Indebtedness” shall not include obligations in respect of deposits received in the ordinary course of Dealer’s banking business, (ii) the phrase “or becoming capable at such time of being declared” shall be deleted from clause (1) of such Section 5(a)(vi) and (iii) the following language shall be added to the end thereof “Notwithstanding the foregoing, a default under subsection (2) hereof shall not constitute an Event of Default if (x) the default was caused solely by error or omission of an administrative or operational nature; (y) funds were available to enable the party to make the payment when due; and (z) the payment is made within two Local Business Days of such party’s receipt of written notice of its failure to pay.”; and

(c) following the payment of the Premium, the condition precedent in Section 2(a)(iii)(1) of the Agreement with respect to Events of Default or Potential Events of Default (other than an Event of Default or Potential Event of Default arising under Section 5(a)(ii) or 5(a)(iv) of the Agreement) shall not apply to a payment or delivery owing by Dealer to Counterparty.

In the event of any inconsistency between provisions of the Agreement and this Confirmation, this Confirmation will prevail for the purpose of the Transaction to which this Confirmation relates. The parties hereby agree that no transaction other than the Transaction to which this Confirmation relates shall be governed by the Agreement. If there exists any ISDA Master Agreement between Dealer and Counterparty or any confirmation or other agreement between Dealer and Counterparty pursuant to which an ISDA Master Agreement is deemed to exist between Dealer and Counterparty, then notwithstanding anything to the contrary in such ISDA Master Agreement, such confirmation or agreement or any other agreement to which Dealer and Counterparty are parties, the Transaction shall not be considered a Transaction under, or otherwise governed by, such existing or deemed ISDA Master Agreement.

2.    The terms of the particular Transaction to which this Confirmation relates are as follows:

General Terms.

Procedures for Exercise.

[For the purposes of determining whether any conversion of a Convertible Note will be an Early Conversion hereunder or an “Early Conversion” under the Base Call Option Transaction Confirmation, a conversion of a Convertible Note pursuant to the Indenture shall be allocated first to the Base Call Option Transaction Confirmation (as defined below) until all Options thereunder are exercised or terminated.]

Notwithstanding the foregoing, in no event shall the number of Options that are exercised or deemed exercised hereunder exceed the Number of Options.

Automatic Exercise After Free

Notwithstanding the foregoing, in no event shall the number of Options that are exercised or deemed exercised hereunder exceed the Number of Options.

Settlement and the Specified Cash Amount (as defined below) is not USD 1,000, (y) Cash Settlement or (z) Combination Settlement, Counterparty shall provide Dealer a separate notice (the “Notice of Final Settlement Method”) (which, for the avoidance of doubt, may be by email) in respect of all such Convertible Notes before 5:00 p.m. (New York City time) on the Free Convertibility Date specifying (1) the Relevant Settlement Method for such Options, and (2) if the settlement method for the related Convertible Notes is not Settlement in Shares or Settlement in Cash (each as defined below), the fixed amount of cash per Convertible Note that Counterparty has elected to deliver to Holders (as such term is defined in the Indenture) of the related Convertible Notes (the “Specified Cash Amount”) and if Counterparty fails to timely provide such Notice of Final Settlement Method, it shall be deemed to have provided a Notice of Final Settlement Method indicating that the Relevant Settlement Method is Net Share Settlement and that the settlement method for the related Convertible Notes is a combination of cash and shares with a Specified Cash Amount of USD 1,000. Counterparty acknowledges its responsibilities under applicable securities laws, and in particular Section 9 and Section 10(b) of the Exchange Act (as defined below) and the rules and regulations thereunder, in respect of any election of a settlement method with respect to the Convertible Notes that is not Net Share Settlement with a Specified Cash Amount of USD 1,000.

[Any “Notice of Exercise” and “Notice of Final Settlement Method” delivered to Dealer pursuant to the Base Call Option Transaction Confirmation shall be deemed to be a Notice of Exercise and a Notice of Final Settlement Method (as the case may be) pursuant to this Confirmation and the terms of such Notice of Exercise and Notice of Final Settlement Method (as the case may be) shall apply, mutatis mutandis, to this Confirmation.]

“‘Market Disruption Event’ means, in respect of a Share, (i) a failure by the primary United States national or regional securities exchange or market on which the Shares are listed or admitted for trading to open for trading during its regular trading session or (ii) the occurrence or existence prior to 1:00 p.m. (New York City time) on any Scheduled Valid Day for the Shares for more than one half-hour period in the aggregate during regular trading hours of any suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant stock

exchange or otherwise) in the Shares or in any options contracts or futures contracts relating to the Shares.”

Settlement Terms.

(i)    if Counterparty has elected to settle its conversion obligations in respect of the related Convertible Note (A) entirely in Shares pursuant to Section [14.02(a)(iv)(A)] of the Indenture (together with cash in lieu of fractional Shares) (such settlement method, “Settlement in Shares”), (B) in a combination of cash and Shares pursuant to Section [14.02(a)(iv)(C)] of the Indenture with a Specified Cash Amount less than USD 1,000 (such settlement method, “Low Cash Combination Settlement”) or (C) in a combination of cash and Shares pursuant to Section [14.02(a)(iv)(C)] of the Indenture with a Specified Cash Amount equal to USD 1,000, then, in each case, the Relevant Settlement Method for such Option shall be Net Share Settlement;

(ii)    if Counterparty has elected to settle its conversion obligations in respect of the related Convertible Note in a combination of cash and Shares pursuant to Section [14.02(a)(iv)(C)] of the Indenture with a Specified Cash Amount greater than USD 1,000, then the Relevant Settlement Method for such Option shall be Combination Settlement; and

(iii)    if Counterparty has elected to settle its conversion obligations in respect of the related Convertible Note entirely in cash pursuant to Section [14.02(a)(iv)(B)] of the Indenture (such settlement method, “Settlement in Cash”), then the Relevant Settlement Method for such Option shall be Cash Settlement.

Dealer will pay cash in lieu of delivering any fractional Shares to be delivered with respect to any Net Share

Settlement Amount valued at the Relevant Price for the last Valid Day of the Settlement Averaging Period.

Dealer will pay cash in lieu of delivering any fractional Shares to be delivered with respect to any Combination Settlement Share Amount valued at the Relevant Price for the last Valid Day of the Settlement Averaging Period.

that if the calculation contained in clause (ii) above results in a negative number, the Daily Option Value for such Valid Day shall be deemed to be zero. In no event will the Daily Option Value be less than zero.

3.    Additional Terms applicable to the Transaction.

Adjustments applicable to the Transaction:

Notwithstanding the foregoing and “Consequences of Merger Events / Tender Offers” below:

or its board of directors (including, without limitation, pursuant to Section [14.05] of the Indenture, Section [14.07] of the Indenture or any supplemental indenture entered into thereunder or in connection with any proportional adjustment or the determination of the fair value of any securities, property, rights or other assets), then in each such case, the Calculation Agent will determine in good faith and in a commercially reasonable manner the adjustment to be made to any one or more of the Strike Price, Option Entitlement and any other variable relevant to the exercise, settlement or payment for the Transaction in a commercially reasonable manner, taking into account the relevant provisions of the Indenture; provided that, notwithstanding the foregoing, if any Potential Adjustment Event occurs during the Settlement Averaging Period but no adjustment was made to any Convertible Note under the Indenture because the relevant Holder (as such term is defined in the Indenture) was deemed to be a record owner of the underlying Shares on the related Conversion Date, then the Calculation Agent shall make a commercially reasonable adjustment to the terms hereof in order to account for such Potential Adjustment Event;

manner contemplated by the relevant Dilution Adjustment Provision based on such declaration or (c) the “Conversion Rate” (as defined in the Indenture) is adjusted as a result of such Potential Adjustment Event and subsequently re-adjusted (each of clauses (a), (b) and (c), a “Potential Adjustment Event Change”) then, in each case, the Calculation Agent shall have the right to adjust in a good faith and commercially reasonable manner, any variable relevant to the exercise, settlement or payment for the Transaction as appropriate to reflect the costs (to account solely for hedging mismatches and market losses) and expenses incurred by Dealer in connection with its hedging activities, with such adjustments made assuming that Dealer maintains commercially reasonable hedge positions, as a result of such Potential Adjustment Event Change.

Extraordinary Events applicable to the Transaction:

Consequences of Merger Events/

any State thereof or the District of Columbia, then, in either case, Cancellation and Payment (Calculation Agent Determination) may apply at Dealer’s sole election; provided further that, for the avoidance of doubt, adjustments shall be made pursuant to the provisions set forth above regardless of whether any Merger Event or Tender Offer gives rise to an Early Conversion.

intention that is the subject of an announcement of the type described in clause (i) or (ii) of this sentence (including, without limitation, a new announcement, whether or not by the same party, relating to such a transaction or intention or the announcement of a withdrawal from, or the abandonment or discontinuation of, such a transaction or intention), as determined by the Calculation Agent in good faith and in a commercially reasonable manner. For the avoidance of doubt, the occurrence of an Announcement Event with respect to any transaction or intention shall not preclude the occurrence of a later Announcement Event with respect to such transaction or intention.

Additional Disruption Events:

Following any determination or calculation by Determining Party hereunder, upon a written request by Counterparty (which may be by email), Determining Party will promptly (but in any event within five Scheduled Trading Days) provide to Counterparty by email to the email address provided by Counterparty in such written request a report (in a commonly used file format for the storage and manipulation of financial data) displaying in reasonable detail the basis for such determination or calculation (including any assumptions used in making such determination or calculation), it being understood that in no event will Determining Party be obligated to share with Counterparty any proprietary or confidential data or information or any proprietary or confidential models used by it in making such determination or calculation or any information that is subject to an obligation not to disclose such information.    

Agreements and Acknowledgments

Following any adjustment, determination or calculation by the Calculation Agent hereunder, upon a written request by Counterparty (which may be by email), the Calculation Agent will promptly (but in any event within five Scheduled Trading Days) provide to Counterparty by email to the email

address provided by Counterparty in such written request a report (in a commonly used file format for the storage and manipulation of financial data) displaying in reasonable detail the basis for such adjustment, determination or calculation (including any assumptions used in making such adjustment, determination or calculation), it being understood that in no event will the Calculation Agent be obligated to share with Counterparty any proprietary or confidential data or information or any proprietary or confidential models used by it in making such adjustment, determination or calculation or any information that is subject to an obligation not to disclose such information.

All calculations and determinations by the Calculation Agent shall be made in good faith and in a commercially reasonable manner.

5.    Account Details.

6.    Offices.

7.    Notices.

8.    Representations and Warranties.

Each of the representations and warranties of Counterparty set forth in Section 3 of the Purchase Agreement (the “Purchase Agreement”) dated as of April [__], 2020, between Counterparty and Morgan Stanley & Co. LLC and Goldman Sachs & Co. LLC as representatives of the Initial Purchasers party thereto (the “Initial Purchasers”), are true and correct and are hereby deemed to be repeated to Dealer as if set forth herein. Counterparty hereby further represents and warrants to Dealer on the date hereof and on and as of the Premium Payment Date that:

from any person or entity) as a result of Dealer or its affiliates owning or holding (however defined) Shares; provided that Counterparty makes no representation or warranty regarding any such requirement that is applicable generally to the ownership of common equity securities of U.S. domestic issuers listed on the Exchange by Dealer or any of its affiliates solely as a result of it or any of such affiliates being a financial institution or broker dealer.

Dealer hereby represents and warrants to Counterparty on the date hereof and on and as of the Premium Payment Date, that Dealer is an “eligible contract participant” (as such term is defined in Section 1a(18) of the Commodity Exchange Act, other than a person that is an eligible contract participant under Section 1a(18)(C) of the Commodity Exchange Act).

9.    Other Provisions.

Dealer with a Repurchase Notice in accordance with this paragraph, such Indemnified Person shall promptly notify Counterparty in writing, and Counterparty, upon request of the Indemnified Person, shall retain counsel reasonably satisfactory to the Indemnified Person to represent the Indemnified Person and any others Counterparty may designate in such proceeding and shall pay the reasonable fees and expenses of such counsel related to such proceeding. Counterparty shall not be liable to the extent that the Indemnified Person fails to notify Counterparty within a commercially reasonable period of time after any action is commenced against it in respect of which indemnity may be sought hereunder (it being understood that any such notice delivered within 30 calendar days of the commencement of any such action shall be deemed to have been delivered within a commercially reasonable period of time for such purpose). In addition, Counterparty shall not have liability for any settlement of any proceeding contemplated by this paragraph that is effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, Counterparty agrees to indemnify any Indemnified Person from and against any loss or liability by reason of such settlement or judgment. Counterparty shall not, without the prior written consent of the Indemnified Person, effect any settlement of any such proceeding contemplated by this paragraph that is pending or threatened in respect of which any Indemnified Person is or could have been a party and indemnity could have been sought hereunder by such Indemnified Person, unless such settlement includes an unconditional release of such Indemnified Person from all liability on claims that are the subject matter of such proceeding on terms reasonably satisfactory to such Indemnified Person. Counterparty shall not be liable for any losses, claims, damages or liabilities (or expenses relating thereto) of any Indemnified Person that result from the bad faith, gross negligence, willful misconduct or fraud of such Indemnified Person. If the indemnification provided for in this paragraph is unavailable to an Indemnified Person or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then Counterparty hereunder, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities. The remedies provided for in this paragraph ‎(b) are not exclusive and shall not limit any rights or remedies which may otherwise be available to any Indemnified Person at law or in equity. The indemnity and contribution agreements contained in this paragraph shall remain operative and in full force and effect regardless of the termination of the Transaction.

and Counterparty, as are reasonably requested and reasonably satisfactory to Dealer;

condition described in clauses (A), (B) or (C), an “Excess Ownership Position”), Dealer is unable after using its commercially reasonable efforts to effect a transfer or assignment of Options to a third party on pricing terms reasonably acceptable to Dealer and within a time period reasonably acceptable to Dealer such that no Excess Ownership Position exists, then Dealer may designate any Exchange Business Day as an Early Termination Date with respect to a portion of the Transaction (the “Terminated Portion”), such that following such partial termination no Excess Ownership Position exists. In the event that Dealer so designates an Early Termination Date with respect to a portion of the Transaction, a payment shall be made pursuant to Section 6 of the Agreement as if (1) an Early Termination Date had been designated in respect of a Transaction having terms identical to the Transaction and a Number of Options equal to the number of Options underlying the Terminated Portion, (2) Counterparty were the sole Affected Party with respect to such partial termination and (3) the Terminated Portion were the sole Affected Transaction (and, for the avoidance of doubt, the provisions of Section ‎9(l) shall apply to any amount that is payable by Dealer to Counterparty pursuant to this sentence as if Counterparty was not the Affected Party). Dealer shall notify Counterparty of an Excess Ownership Position with respect to which it intends to seek a transfer or assignment as soon as reasonably practicable after becoming aware of such an Excess Ownership Position. The “Section 16 Percentage” as of any day is the fraction, expressed as a percentage, (A) the numerator of which is the number of Shares that Dealer and any other person subject to aggregation with Dealer for purposes of the “beneficial ownership” test under Section 13 of the Exchange Act, or any “group” (within the meaning of Section 13 of the Exchange Act) of which Dealer is or may be deemed to be a part beneficially owns (within the meaning of Section 13 of the Exchange Act), without duplication, on such day (or, to the extent that for any reason the equivalent calculation under Section 16 of the Exchange Act and the rules and regulations thereunder results in a higher number, such higher number) and (B) the denominator of which is the number of Shares outstanding on such day. The “Option Equity Percentage” as of any day is the fraction, expressed as a percentage, (A) the numerator of which is the sum of (1) the product of the Number of Options and the Option Entitlement and (2) the aggregate number of Shares underlying any other call option transaction sold by Dealer to Counterparty, and (B) the denominator of which is the number of Shares outstanding. The “Share Amount” as of any day is the number of Shares that Dealer and any person whose ownership position would be aggregated with that of Dealer (Dealer or any such person, a “Dealer Person”) under any law, rule, regulation, regulatory order or organizational documents or contracts of Counterparty that are, in each case, applicable to ownership of Shares (“Applicable Restrictions”), owns, beneficially owns, constructively owns, controls, holds the power to vote or otherwise meets a relevant definition of ownership under any Applicable Restriction, as determined by Dealer in its reasonable discretion. The “Applicable Share Limit” means a number of Shares equal to (A) the minimum number of Shares that could give rise to reporting or registration obligations or other requirements (including obtaining prior approval from any person or entity) of a Dealer Person (except for filings of Form 13F, Schedule 13D or Schedule 13G under the Exchange Act), or could result in an adverse effect on a Dealer Person, under any Applicable Restriction, as determined by Dealer in its reasonable discretion, minus (B) 1% of the number of Shares outstanding.

deliver, or to acquire Shares to deliver, any or all of the Shares to be delivered by Dealer on any Settlement Date for the Transaction, Dealer may, by notice to Counterparty on or prior to any Settlement Date (a “Nominal Settlement Date”), elect to deliver the Shares on two or more dates (each, a “Staggered Settlement Date”) as follows:

[minus the “Affected Number of Options” (as defined in the Base Call Option Confirmation), if any, that relate to such Affected Convertible Notes] and (y) the Number of Options as of the Conversion Date for such Early Conversion;

Indenture or otherwise) by Counterparty or any of its subsidiaries, (ii) any Convertible Notes are delivered to Counterparty in exchange for delivery of any property or assets of Counterparty or any of its subsidiaries (howsoever described), (iii) any principal of any of the Convertible Notes is repaid prior to the final maturity date of the Convertible Notes (other than upon acceleration of the Convertible Notes described in Section 9(h)(iii)), or (iv) any Convertible Notes are exchanged by or for the benefit of the Holders (as defined in the Indenture) thereof for any other securities of Counterparty or any of its Affiliates (or any other property, or any combination thereof) pursuant to any exchange offer or similar transaction; provided that any conversion of Convertible Notes pursuant to the terms of the Indenture shall not constitute a Repurchase Event.

Termination Date or date of cancellation, as applicable, of its election that the Share Termination Alternative shall not apply, (b) Counterparty remakes the representation set forth in Section ‎8(f) as of the date of such election and (c) Dealer agrees, in its good faith discretion, to such election, in which case the provisions of Section 12.7 or Section 12.9 of the Equity Definitions, or the provisions of Section 6(d)(ii) and Section 6(e) of the Agreement, as the case may be, shall apply.

Settled” and all references to “Shares” shall be read as references to “Share Termination Delivery Units”. “Share Termination Settled” in relation to the Transaction means that Share Termination Alternative is applicable to the Transaction.

than 40 Valid Days after the original Valid Day or other date of valuation, payment or delivery, as the case may be.

“QFC Stay Rules” means the regulations codified at 12 C.F.R. 252.2, 252.81–8, 12 C.F.R. 382.1-7 and 12 C.F.R. 47.1-8, which, subject to limited exceptions, require an express recognition of the stay-and-transfer powers of the FDIC under the Federal Deposit Insurance Act and the Orderly Liquidation Authority under Title II of the Dodd Frank Wall Street Reform and Consumer Protection Act and the override of default rights related directly or indirectly to the entry of an affiliate into certain insolvency proceedings and any restrictions on the transfer of any covered affiliate credit enhancements.]

Please confirm that the foregoing correctly sets forth the terms of our agreement by executing this Confirmation and returning it to [Dealer].

Very truly yours,