US Tax Filing Instruction Booklet

In connection with the 2017 Property sales and 2017 distributions by Sunstone U.S. Opportunity (No. 3) Realty Trust and Sunstone U.S. Opportunity (No. 4) Realty Trust (collectively known as “Sunstone”).1

All Unitholders must log on to our secured website to complete a simple Online Questionnaire in order to:

1. Obtain US tax slips to file a 2017 US federal income tax return, claim any applicable US tax refund for any US tax over-withholdings and/or US tax capital loss carryover; and

2. Establish your final US federal income tax liability to support your claim of a foreign tax credit or deduction, where applicable, on your 2017 Canadian income tax return.

The related Unitholder US tax compliance process is time sensitive. Your immediate attention to the matters contained herein is suggested.

The deadline for providing your information to Sunstone through the secured web-based system is before midnight (Pacific Standard Time) on April 1, 2018.

The information included in this instruction booklet is of a general nature only and is not intended to be, nor should it be construed as legal or tax advice to any Unitholder of Sunstone. Unitholders should consult their own tax advisors concerning the tax consequences to them of the 2017 capital loss for the Sunstone U.S. Opportunity (No. 3) Realty Trust as well as the 2017 capital gain dividend for the Sunstone U.S. Opportunity (No. 4) Realty Trust, having regard to each Unitholder’s particular circumstances.

Please review this instruction booklet very carefully and consult your tax advisor as to the proper completion and delivery of the US Tax ID application and/or US federal income tax return (including the applicable filing deadlines).

1 For the purposes of this booklet, the term “Sunstone” refers only to Sunstone U.S. Opportunity (No. 3) Realty Trust and Sunstone

U.S. Opportunity (No. 4) Realty Trust.

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Table of Contents

Summary of 2017 Property Sales and Related US Tax Compliance Requirements ................................... 3

Key Information (Including Action Items and Dates) .................................................................................. 8

Appendix A: Checklist of Information Required to Complete the Online Questionnaire ....................... 12

Appendix B: Instructions on How to Certify a Copy of Your Passport...................................................... 19

Appendix C: Filing Instructions for Individual US Tax ID Application/Renewal ....................................... 20

Appendix D: Filing Instructions for Entity US Tax ID Application ............................................................. 21

Appendix E: Form PPTC 516 – Request for Certified True Copy of Canadian Travel Document ............. 22

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Summary of 2017 Property Sales and Related US Tax Compliance Requirements

As communicated to you in Sunstone’s press release dated January 10, 2018, Sunstone U.S. Opportunity (No. 3) Realty Trust completed the sales of its 10% interest in Grand Parkway Apartments and the sales of units in Sunstone U.S. (No. 3) LP that held the Embassy Suites Tempe Hotel (collectively referred to as the “2017 Property Sales”).

In addition, in Sunstone’s press release dated January 10, 2018, Sunstone U.S. Opportunity (No. 4) Realty Trust completed the sales of the 90% interest in the Grand Parkway Apartments and the sales of units in Sunstone U.S. (No. 4) LP that held the Embassy Suites Dallas Fort Worth Hotel respectively (collectively referred to as the “2017 Property Sales”).

Sunstone U.S. Opportunity (No. 3) Realty Trust (“Sunstone U.S. (No. 3)”)

The 2017 Property Sales by Sunstone U.S. (No. 3) resulted in a net US tax capital loss.

No withholding tax was withheld and remitted to the IRS from the 2017 distributions paid to Unitholders. Therefore, Unitholders in Sunstone U.S. (No. 3) (with no investment in Sunstone U.S. (No. 4) will not receive a US tax refund as no US tax withholdings were made on his/her share of the capital gain dividends.

However, Unitholders should still obtain the US tax slips reporting their share of the net US tax capital loss. Unitholders in Sunstone U.S. (No. 3) (with no investment in Sunstone U.S. (No. 4) should consult with a tax professional with any questions related to their personal tax circumstances, including whether the Unitholder’s share of net US tax capital loss reported on Sunstone U.S. (No. 3)’s 2017 tax slip may be available as a carryback or carryforward on the Unitholder’s US federal income tax return.

Sunstone U.S. Opportunity (No. 4) Realty Trust (“Sunstone U.S. (No. 4)”)

In 2017, Sunstone U.S. (No. 4) made a return of capital and capital gain dividend of proceeds from the 2017 Property Sales to all Unitholders of record as at the respective distribution dates. Under US tax law, Sunstone U.S. (No. 4) is required to withhold and remit 35 percent of the capital gain dividend to the Internal Revenue Service (IRS).

The maximum US federal income tax rate for long term capital gains of a non-US resident individual Unitholder is generally 20 percent (or 25 percent if attributable to certain depreciation recapture). Therefore, a Unitholder’s actual US federal tax liability on the capital gain dividend may be less than the amount withheld at 35 percent.

As the capital gain dividend is attributable to gain from US real property, each Sunstone U.S. (No. 4) Unitholder2 is required to file a US federal income tax return for the 2017 taxation year.

By filing a US federal income tax return, a Sunstone U.S. (No. 4) Unitholder can obtain the applicable US tax refund for any US tax over-withholdings on his/her share of the capital gain dividend. Also, a Unitholder must file a US federal income tax return to establish his/her final US federal income tax liability to support the Unitholder’s claim for a foreign tax credit or deduction, where applicable, on the Unitholder’s 2017 Canadian income tax return.

The following example illustrates the potential refund that might be applicable to a non-US resident individual Investor based on a $10,000 capital gain dividend (e.g., $1,000 capital gain dividend per unit for 10 units).

2 References to Investor means a Unitholder of Sunstone that is not a United States person.

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This example is for illustration purposes only; the actual capital gain dividend, US tax liability, and US tax refund will vary.

Description Estimated US Tax Liability

Amount received by the Non-US Resident Individual Investor

35% US tax withheld and remitted to the Internal Revenue Service

($3,500)

Net amount distributed to the non-US resident individual Investor

$6,500

20% individual tax rate on capital gain dividend received (assumes equals actual tax

liability)3

$2,000

US tax refund ($1,500) $1,500

If you hold both Sunstone U.S. (No. 3) and Sunstone U.S. (No. 4)

Please note, if Unitholders hold both Sunstone U.S. (No. 3) and Sunstone U.S. (No. 4) you may have a lower, if any, US federal tax liability as tax capital losses from Sunstone U.S. (No. 3) may reduce or offset the capital gain from Sunstone U.S. (No. 4).

US Individual Tax Identification Numbers

Each Unitholder requires a US Tax ID4 to file a US federal income tax return and to obtain a US tax slip from Sunstone (i.e., Form 8805) to claim any applicable US tax refund and/or US tax capital loss carryover.

Please consult with your financial advisor or tax advisor as many Unitholders in Sunstone U.S. (No. 3) may already have a US Tax ID.

The 2017 Online Questionnaire

A secured, online system for the 2017 Online Questionnaire will be provided Feburary 1, 2018 to April 1, 2018 (the Website) to provide assistance to Unitholders with the 2017 US tax compliance requirements related to the 2017 Property Sales.

In particular, this secured website provides a simple Online Questionnaire for each Unitholder to complete and submit.

The purpose of the Online Questionnaire is to collect information from you (the Unitholder):

■ To allow you to obtain US tax slips from Sunstone so you can file a 2017 US federal income tax return and obtain any applicable US tax refund for any US tax over-withholdings on your capital gain dividend and/or US tax capital loss carryover.

■ To allow you to apply for a US Tax ID, if eligible (if you do not already have a US Tax ID).

■ Note: Many Unitholders from Sunstone U.S. Opportunity (No. 3) Realty Trust may already have a US Tax ID from Sunstone’s previous 2014 capital gain dividend. If you are a Unitholder in

3 The 20 percent rate is the maximum rate on long term capital gain. The actual rate may be less, depending on the investor’s US

graduated tax rate for 2017. 4 US Tax ID refers to an Individual Tax Identification Number or a Social Security Number for an individual and an Employer

Identification Number for a corporation, partnership, trust, or any other entity.

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Sunstone U.S. (No. 3) and do not have a US Tax ID number, please contact Sunstone at (604) 449-6402 for further instructions.

■ To prepare a US federal income tax return (Form 1040NR) for you to allow you to report your capital gain dividend and claim any applicable US tax refund and/or capital loss carryforwards.

Note: This option is only available to non-US resident individuals who would not otherwise have a US federal income tax filing requirement, but for the receipt of the capital gain dividend.

The Online Questionnaire will only be available on the Sunstone website from February 1, 2018 to April 1, 2018.

**IMPORTANT** If a Unitholder does not submit the required information through the Website by April 1, 2018, the Unitholder will NOT be able to obtain the required US tax slips to file their US

federal income tax return and claim any applicable refund for any US tax over-withholding and/or capital loss carryovers.

Determining Validity of US Individual Tax Identification Number (ITIN) Due to recent changes to US tax laws, ITINs that have NOT been used on a US federal tax return at least once in the last three consecutive tax years (i.e., 2014, 2015, 2016) will expire on December 31, 2017. All ITINs with middle digits 70, 71, 72 or 80 will expire on December 31, 2017. Examples of such numbers include 9NN-70-NNNN or 9NN-72-NNNN. ITINs with middle digits of 78 and 79 expired on December 31, 2016. ITINs that expired on December 31, 2016 or will expire on December 31, 2017 can be renewed at any time. Affected individuals who expect to file a US federal tax return in 2018 with respect to their 2017 US taxable income must submit a renewal application. Delays in processing the relevant 2017 tax return and any related tax refund will result if an individual attempts to file a return with an expired ITIN. Once you have successfully renewed your ITIN, the IRS will not issue you a new ITIN, and you will continue to use your original ITIN instead.

ITIN Renewal Process The process to renew an ITIN is the same process outlined in Appendix C. You must include a copy of your passport that has been certified by the original issuing agency (e.g., the Canadian Passport Agency) in order to verify your identity. If you do not have a passport, please contact Sunstone at (604) 449-6402 for assistance. When submitting Form W-7 to renew your ITIN, you must include your previously assigned ITIN and the name under which you applied for the original ITIN on line 6f to avoid delays in processing your Form W-7. If your legal name has changed since the original assignment of your ITIN, you will need to attach documentation, such as your marriage certificate or a court order, to Form W-7 to support the reason for your legal name change. Further information and access to frequently asked questions can be found at https://www.irs.gov/individuals/individual-taxpayer-identification-number

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Sunstone Prospectus and Commentaries

The Final Prospectus for Sunstone U.S. Opportunity (No. 3) Realty Trust is dated September 28, 2010. Unitholders should carefully review the prospectus including, and without limitation, the description of the Canadian Federal Income Tax Considerations contained on pages 63 to 74 of the Sunstone U.S. (No. 3) Prospectus, as well as the US Federal Income Tax Considerations contained on pages 75 to 96 of the Sunstone U.S. (No. 3) Prospectus (the “Commentaries”).

The Final Prospectus for Sunstone U.S. Opportunity (No. 4) Realty Trust is dated April 27, 2011. Unitholders should carefully review the prospectus including, and without limitation, the description of the Canadian Federal Income Tax Considerations contained on pages 66 to 76 of the Sunstone U.S. (No. 4) Prospectus, as well as the US Federal Income Tax Considerations contained on pages 77 to 98 of the Sunstone U.S. (No. 4) Prospectus (the “Commentaries”).

The Prospectuses may be viewed under Sunstone U.S. Opportunity (No. 3) Realty Trust and Sunstone U.S. Opportunity (No. 4) Realty Trust profiles on the SEDAR website at http://www.sedar.com.

The Commentaries were current as of the date of each respective Prospectus, and both the Commentaries and this compliance instruction booklet are of a general nature only and are not intended to be nor should be construed as legal advice or tax advice to any Unitholder of Sunstone.

Each Unitholder is strongly encouraged to obtain independent professional tax advice regarding their own situation with respect to the tax consequences of holding Units in the 2017 fiscal year, and receiving distributions and allocations from Sunstone, considering any legislative changes since the date of the Prospectus and having regard to their particular circumstances.

Implication to Canadian Tax Reporting

A Unitholder is generally required to file a US federal income tax return to establish their final US federal income tax liability to support the Unitholder’s claim for a foreign tax credit or deduction, where applicable, on the Unitholder’s Canadian income tax return.

In this regard, it should be noted that a Unitholder’s ability to claim US taxes relating to Units as foreign tax credits or foreign tax deductions for Canadian income tax purposes is complex and will be affected by a number of factors including those relevant to a Unitholder’s own particular circumstances.

Accordingly, Unitholders should consult their own tax advisors regarding their ability to claim foreign tax credits or foreign tax deductions for US taxes paid in respect of Units.

Units Held in RRSPs or Plans

A registered retirement savings plan (“RRSP”) is a separate person from its annuitant for Canadian income tax purposes. However, for US tax purposes, generally an annuitant should report the investment in Sunstone and file a US tax return, as described in this information booklet and in the Commentaries. The US tax treatment and classification of RRSPs is complex, is not free from doubt, and is dependent upon the terms of the specific RRSP. RRSPs holding Units, and their annuitants, should consult their own tax advisors as to their US and Canadian tax consequences.

Even though US tax was paid on Units held in an RRSP, and although an annuitant will generally file a US federal income tax return, an RRSP will not be entitled to foreign tax credits or foreign tax deductions for Canadian tax purposes in respect of any US taxes attributable to the Units. Furthermore, to the extent that an annuitant (rather than the RRSP itself) receives and keeps a refund of (or attempts to claim a foreign tax credit or a foreign tax deduction on) US tax attributable to Units in an RRSP, the annuitant may, depending on the circumstances, be required for Canadian tax purposes to have an income inclusion or to pay additional tax. In this regard, certain of Canada Revenue Agency’s interpretations, taken in

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different contexts, have been that where a payment arising because of an investment made by an RRSP, is either deposited directly to the RRSP or received by its annuitant but immediately (or within a reasonable time) returned to the RRSP, the payment would generally be treated as though it was never outside of the RRSP. Annuitants of RRSPs that hold Units should consult their tax advisors to consider endorsing refunds directly to their RRSP trustees. Holders of Units that are RRSPs and their annuitants should also consult their own tax advisors in regards to all the foregoing matters as they apply to their specific circumstances.

Holders of Units that are registered education savings plans, registered retirement income funds, deferred profit sharing plans and tax-free savings accounts (referred to as “Plans”), and their annuitants, beneficiaries or holders, as the case may be, may have similar tax considerations as generally outlined above. However, the US and Canadian tax treatment and classification of various Plans is complex, is not free from doubt, and is dependent upon the terms of the specific Plans. Plans holding Units, and their annuitants, beneficiaries or holders, should consult their own tax advisors as to their US and Canadian tax consequences.

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Key Information

■ US Tax Filing Website: A link will be provided from February 1, 2018 to April 1, 2018.

■ Online Questionnaire Technical Assistance Hotline and Email:

Darlene Paziuk

Direct: 604-449-6402 or Toll Free: 1-888-681-5959 ext. 1555

dpaziuk@sunstoneadvisors.com

The Technical Assistance Hotline will be available from February 1, 2018 to April 1, 2018. Hours of operation will be from 8:00 am to 4:00 pm (Pacific Standard Time) Monday to Friday (excluding holidays).

The telephone hotline and email address are for the Online Questionnaire technical assistance ONLY.

We recommend you consult with your tax advisor for specific Canadian and US tax advice in respect of the 2017 Property Sales and your receipt of the capital gain dividend.

Key Action Items and Dates:

Action Item Date of Completion

1. Individual investors confirm US Tax ID exists and is valid:

■ Double check that you don’t already have a US Tax ID (see FAQ #15).

■ Confirm that your US Tax ID has not expired or will not expire by December 31, 2017 (see Determining Validity of US Tax ID on page 5 for details).

■ Call Sunstone at (604) 449-6402 for additional instructions if you are a Unitholder in Sunstone U.S. Opportunity (No. 3) Realty Trust and you submitted a US tax return for the 2014 capital gain dividend but you do not have a US Tax ID.

If you determined that you need to obtain a US Tax ID or need to renew your US Tax ID, then:

■ Check that your passport will be valid for at least 7 months after the date you plan to submit the Online Questionnaire. If not, renew your passport.

■ Obtain a certified copy of your passport (see instructions in Appendix B)

As soon as possible

2. Complete the 2017 Online Questionnaire by going to the secure online link that will be provided February 1, 2018 to

April 1, 2018.5

Starting February 1, 2018 and before midnight on April 1, 2018.

5 Your US tax slips/returns will be compiled solely on the information you submit. It is your responsibility to ensure the information

is in compliance with the requirements imposed under the Internal Revenue Code (the Code) (or applicable state tax law) with respect to the US tax slips/returns.

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Action Item Date of Completion

■ Please prepare all the information listed in Appendix A before going to the website.

■ You will receive a confirmation email with your reference number after you have successfully completed and submitted your Online Questionnaire on the Website. Please keep the reference number in a safe and secure place. If you selected the option to receive your tax forms by email, you will need this reference number to access your tax forms.

Note: If a Unitholder does not submit the required information using the Website by midnight on April 1, 2018, he/she will not be able to obtain the required US tax slips to file a US federal income tax return and claim any applicable refunds for US tax over-withholdings and or any tax capital loss carryovers.

3. Unitholders who do not have a US Tax ID or need their existing US Tax ID to be renewed and elect not to use the Website to prepare their US Tax ID application or renewal can complete either Form W-7 (if the Unitholder is an individual) or Form SS-4 (if the Unitholder is a corporation, partnership, trust, or any other entity) on their own. Both forms are available from the IRS website at http://www.irs.gov/. Please consult with your own US tax advisor regarding completion and filing of these forms.

If you are an individual applying for a US ITIN, we recommend filing your Form W-7 with your US tax return to minimize the risk of your application being rejected by the IRS.

If you are an individual renewing a US ITIN, you may renew your ITIN by filing Form W-7 with your US tax return or by filing it with the IRS at any time before filing your US tax return.

(6) As a result of certain regulatory ethics and independence rules, Sunstone’s service provider, KPMG LLP (KPMG), may be restricted

from providing personal tax services to an individual and his/her immediate family members (i.e., spouse, spouse equivalent or dependent). The restriction may apply if the individual or an immediate family member of the individual hold one of the following financial reporting positions in a publicly traded company, or one of its subsidiaries, of which KPMG is the auditor: the Chief Executive Officer, President, Chief Financial Officer, Chief Operating Officer, general counsel, Chief Accounting Officer, controller, director of internal audit, director of financial reporting, treasurer or any equivalent position. The questionnaire will ask each individual investor certain information so that KPMG can determine whether any conflict or independence issues exist and contact Sunstone immediately if KPMG is unable to assist to a particular investor.

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Action Item Date of Completion

4. Review your US Tax Slips (i.e., Form 8805 and Schedule K-1) and, where applicable, US Tax ID application or renewal and/or US Federal Income Tax Return prepared through the Website (the US Tax Package). (Note: The option to use the Website to prepare a US federal income tax return is generally available only for non-US resident individuals who would not otherwise have a US federal income tax filing requirement, but for the receipt of the capital gain dividend.)

If you do not receive your US Tax Package within 4 weeks of receiving a confirmation email, it will be your responsibility to contact the Sunstone hotline.

If you do not agree with the content, calculations, and/or disclosures provided in your US Tax Package, immediately contact the Sunstone hotline.

IMPORTANT: Do not make changes to the US Tax Package (unless specifically instructed by the filing instructions).

As soon as you receive your US Tax Package.

Note: The sooner you complete the Online Questionnaire, the sooner you will receive your US Tax Package. If adjustments are required, additional processing time will be necessary.

5. Sign and send your US Federal Income Tax Return (along with the Form 8805) to the Internal Revenue Service. Keep

one copy for your records.6

On or before April 17, 20187

Before you enter this secured Website to begin the Online Questionnaire, please review the checklist of information set out in Appendix A. Please ensure you have all relevant information available to you when answering the Online Questionnaire.

The Website will be opened on February 1, 2018, after the IRS publishes the 2017 US tax forms. We will provide further information closer to that time.

IMPORTANT: You will receive a reference number in an email upon your completion of the Online Questionnaire on the Website.

Please keep the reference number in a safe and secure place. If you selected to receive your US tax forms by email, you will need this reference number to access your US tax forms.

You have the ultimate responsibility for your own tax return. The Website is intended to prepare the required US tax slips related to the 2017 Property Sales to all Unitholders and, where applicable, certain US federal income tax compliance returns for eligible Unitholders.8

6 Individual investors electing to prepare their relevant US federal income tax return using the Website will receive detailed filing

instructions. Please wait for further information. 7 An individual’s 2017 US federal income tax return (Form 1040NR) is generally due on June 15, 2018. Likewise, a foreign

corporation’s 2017 US federal income tax return (Form 1120-F) is generally due by the 15th day of the 6th month after the end of its tax year if the foreign corporation does not maintain an office or place of business in the United States. However, you should prepare your US federal income tax return before filing your Canadian federal income tax return in order to establish your final US tax liability and support your claim of a foreign tax credit or deduction, where applicable, for Canadian income tax purposes.

8 This is generally available only for non-US resident individuals who would not otherwise have a US federal income tax filing requirement, but for the receipt of the capital gain dividend. See also footnote 5.

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Sunstone’s service provider, KPMG, will prepare these returns and forms from the information you submit on the Website. Sunstone and its service provider, KPMG, will not audit or independently investigate or verify the accuracy or completeness of such information provided by you or your representatives on the Website.

Sunstone and its service provider, KPMG, cannot be relied on to uncover errors or irregularities in the underlying information incorporated in your tax returns or the information return, should any exist. However, Sunstone and its service provider, KPMG, will inform you of any such matters that come to our attention. Sunstone and its service provider, KPMG, accept no responsibility or liability for any errors attributable to our reliance upon inaccurate or incomplete information. Sunstone and its service provider, KPMG, strongly recommend that you review the returns before signing and filing them.

ISSUER AND ITS AFFILIATES AND SERVICE PROVIDERS (INCLUDING KPMG) WILL NOT BE LIABLE TO YOU OR ANY OTHER PERSON FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, PUNITIVE, EXEMPLARY OR CONSEQUENTIAL DAMAGES RESULTING FROM, ARISING OUT OF OR IN ANY WAY RELATING TO THE WEBSITE OR YOUR USE OR INABILITY TO USE THE WEBSITE OR THE INFORMATION, DATA, SERVICES OR OTHER MATERIALS ON OR AVAILABLE THROUGH THE WEBSITE, EVEN IF SUNSTONE OR ITS AFFILIATES OR SERVICE PROVIDERS (INCLUDING KPMG) ARE ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

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Appendix A Checklist of Information Required to Complete the Online Questionnaire

Getting Started

Before starting, you will need:

■ Personal information of the Unitholder, including name, address, social insurance number and US Tax ID.

■ The number of units owned by the Unitholder in Sunstone U.S. Opportunity (No. 3) Realty Trust and/or Sunstone U.S. Opportunity (No. 4) Realty Trust9 as at August 15, 2017.

■ Name of brokerage firm (and the related account number) through which you (the Unitholder) hold your interest in Sunstone.

■ The actual number of days the Individual Unitholder has spent in the USA during 2015, 2016 and 2017.

About the Online Questionnaire

The Online Questionnaire is separated into four parts as follows:

1. Section A – 8805 / Schedule K-1 Tax Slips (all Unitholders).

2. Section B – US Tax ID:

a. Individual Taxpayer Identification Number Application (Form W-7) - only for individual investors who do not have a US Tax ID or who need to renew their US Tax ID. Unitholders from Sunstone U.S. (No. 3) should already have a US Tax ID from the Sunstone U.S. (No. 3) 2014 capital gain dividend. If you are an individual investor in Sunstone U.S. (No. 3) and do not have a US Tax ID, please contact Sunstone at 604-449-6402 for further instructions; or

b. SS-4 – only for corporations, partnerships, trusts, or any other entities who do not have a US Tax ID.

3. Section C – Individuals only: Eligibility for Form 1040NR preparation, Financial Reporting Oversight Role Disclosure and Consent to Disclose Tax Return Information.

4. Section D – 1040NR Tax Return (only for non-US resident individual investors who are eligible to use the Website to prepare a US federal income tax return).

Section A – Form 8805 and Schedule K-1

All Unitholders are required to complete Section A – Form 8805 and Schedule K-1.

This Part requires the Unitholder to provide the following information:

1. Type of Investor. Each Unitholder will either be an individual, a corporation, a trust, a partnership, or an estate.

9 For the purposes of this booklet, the term “Sunstone” refers only to Sunstone U.S. Opportunity (No. 3) Realty Trust and Sunstone

U.S. Opportunity (No.4) Realty Trust.

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Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

2. Name of Unitholder. Enter the legal name of the Unitholder (e.g., Joe Smith or ABC Company Ltd.). In general, the Unitholder is the beneficial owner of Sunstone’s Units. For individuals, the legal name provided should be the same as the name on the individual’s passport. If an individual investor holds units through a RRSP or TFSA as a beneficiary, the legal name of the individual investor beneficiary should be used.

The US tax treatment and classification of RRSPs and TFSAs is complex, is not free from doubt and is dependent upon the terms of the specific RRSP/TFSAs. Unitholders that are RRSPs should consult their own tax advisor as to the US federal, state, and local income and other tax consequences to them as a result of their status as an RRSP and their receipt of a capital gain dividend, including which taxpayer should report the capital gain dividend.

3. Address of Unitholder. Provide the address of the Unitholder. In most circumstances, this will be the same address listed on the Unitholder’s income tax return. Please also provide your street address if you have a PO Box Number.

4. Name of brokerage firm through which the Unitholder holds an interest in each of Sunstone U.S. (No. 3) and/or Sunstone U.S. (No. 4) as at August 15, 2017. You can confirm the number of units held by reviewing your brokerage statements or speaking with your broker.

5. The account number(s) for your investment in each of Sunstone U.S. (No. 3) and/or Sunstone U.S. (No. 4). The account number(s) should be indicated on your brokerage firm statement.

6. Joint Accounts. If units are held jointly by spouses, allocate the total number of units between the spouses based on how income from these units were previously divided and reported by each spouse for income tax purposes. Each spouse that is allocated units must separately go to the Website to complete the Online Questionnaire, based on the units that are allocated to each spouse. For example, if spouses jointly own 100 units, and they normally allocate 50 percent of all units to each spouse on their income tax returns, then each spouse will need to complete the Online Questionnaire and report individual ownership of 50 units.

7. US Tax ID. Provide the Unitholder’s valid US Tax ID10.

Individual investors:

1. Have you ever applied for a US Social Security Number, but were not able to obtain one (i.e., received a rejection letter)?

a. Are you currently a US citizen? If yes, please provide your US Social Security Number if you have one. If no, you will be directed to the next question.

b. Were you ever a US citizen? If yes, please provide your US Social Security Number if you have one.

c. If you indicate no US Social Security Number, please confirm if you have renounced your US citizenship.

2. Are you currently a permanent resident (e.g., green card holder) of the US? If yes, please provide your US Social Security Number if you have one.

10 Social security number (SSN), individual taxpayer identification number (ITIN) or employer identification number (EIN).

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Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

3. Do you currently have a valid US work permit (e.g., US visa)?

a. If you currently have a valid US visa, please indicate your visa type. When answering the question on the Website, select one of the visa types on the list. If it is not included on the list, please enter the name of your US visa.

b. Provide your US Social Security Number if you received one with your US visa.

Individuals who are prompted to apply for a Social Security Number (instead of a US ITIN) will be directed to the Social Security Number application form with detailed instructions through the Website link provided upon completion of the Online Questionnaire.

Individuals who are applying for a US ITIN will be prompted to complete Part B of the Online Questionnaire (see below).

Section B – Individual Taxpayer Identification Number Application (Form W-7) - Only Individuals Who Do Not Have a US Individual Tax Identification Number or the US Individual Tax Identification Number has Expired or will Expire on December 31, 2017

A Unitholder who is an individual and does not have a US Tax ID (or their ID has expired) will be prompted to complete Part B of the Online Questionnaire. (Note: An individual investor who has previously filed a tax return with respect to Sunstone U.S. (No. 3)’s 2014 capital gain dividend and does not have a US Tax ID will be prompted to first call Sunstone at (604) 449-6402 for further instructions.)

Part B requires the Unitholder to provide the following information:

1. Birth name of Unitholder. Enter the name as it appears on your birth certificate if it is different from the name entered in Section A above (e.g., maiden name)

2. Date of birth

3. Country of birth

4. Gender

5. Country of citizenship/nationality

6. Non-US tax identification number. For Canadian individuals, this is your social insurance number (SIN)

7. Government-issued passport verifying your identity.

1. Your passport must be valid for at least 7 months from the date of your application

8. Current US visa, including visa type, visa number, and expiry date (if any)

9. Any temporary US taxpayer identification number (TIN) previously issued.

Please see Appendix B for instructions on how to get a certified copy of your passport, which you will need to attach to your US Tax ID application form submitted to the IRS.

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Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

Section B – Entity Taxpayer Identification Number Application (Form SS-4) - Only Entities Who Do Not Have a US Individual Tax Identification Number

1. Name of a responsible party (either an individual or an entity). Responsible party is defined as:

1. For entities with shares or interests traded on a public exchange, or which are registered with the Securities and Exchange Commission (SEC):

i. The principal officer if the business is a corporation

ii. A general partner if a partnership

iii. The owner of an entity that is disregarded as separate from its owner (disregarded entities owned by a corporation should enter the corporation’s name and Employer Identification Number).

iv. A grantor, owner, or trustee, if a trust

2. For all other entities, the person who has a level of control over, or entitlement to, the funds or assets in the entity that, as a practical matter, enables the individual, directly or indirectly, to control, manage, or direct the entity and the disposition of its funds and assets. The ability to fund the entity or the entitlement to the property of the entity alone, however, without any corresponding authority to control, manage, or direct the entity (such as in the case of a minor child beneficiary), does not cause the individual to be a responsible party.

2. US Tax ID11 of the responsible party (if applicable).

3. Identify if the entity is a limited liability company or a foreign equivalent.

4. Entity type of Investor (i.e., partnership, corporation, personal service corporation, church or church-controlled organization, other nonprofit organization, estate, trust, other) and country of organization/incorporation.

5. Closing month of the accounting year of the entity.

6. Identify the principal activity that best describes the business by choosing one of the following: construction, real estate, rental leasing, transportation and warehousing, real estate, manufacturing, finance and insurance. If other, please specify in three words or less.

7. Brief description of your business activity (e.g., principal line of merchandise sold, specific construction work done, products produced, or services provided).

8. Confirm whether the entity has ever applied for and received an Employer Identification Number.

11 Social security number (SSN), individual taxpayer identification number (ITIN) or employer identification number (EIN).

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Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

Section C - Individuals in a “Financial Reporting Oversight Role” (FROR)

To ensure the rules and regulations of the Securities Exchange Commission (SEC) are not violated by any party, Sunstone’s service provider, KPMG, must be informed if any Unitholder that is an individual using the 2017 Online Questionnaire is in a FROR of a publicly-traded company. The SEC’s FROR rules and regulations apply only to individuals.

Persons in a financial reporting oversight role (FROR) are considered to include the Chief Executive Officer, President, Chief Financial Officer, Chief Operating Officer, general counsel, Chief Administrative Officer, controller, director of internal audit, director of financial reporting, treasurer, and any equivalent position.

For this purpose, you will be asked to answer if you and/or an immediate family member [spouse, spousal-equivalent (e.g., common-law or domestic partner), dependent] are in a FROR of a publicly-traded company. If applicable, provide the company name that you, your spouse, spousal equivalent, or dependent are employed.

Individual Investors who are eligible for the Website to prepare their Form 1040NR must consent for KPMG to disclose their tax return information under limited circumstances. Please read the consent in detail. KPMG may decline to prepare your Form 1040NR if you do not consent, in which case, please consult with your tax advisor on your US tax filings.

Section C and Section D–Form 1040NR (only Non-US Resident Individual Investors Who Are Eligible to Use the Website to Prepare a US Federal Income Tax Return)

Unitholders who are non-US resident individuals will be prompted to complete Section C of the Online Questionnaire to determine if they are eligible to prepare the US federal income tax return through this Website. If eligible, Unitholders will be prompted to complete Section D of the Online Questionnaire. Investors will be asked to provide the following information:

1. Did you work in the United States and earn US source income (for example, but not limited to, business income from US self-employment or as a contractor, US employment income) between January 1, 2017 and December 31, 2017 that is reportable on a US federal income tax return?

2. Are you, or were you ever a US citizen?

3. Of what country or countries were you a citizen or national during the tax year?

4. Are you, or were you ever a green card holder (lawful permanent resident) of the United States?

5. Please provide the number of days you were in the US in 2015, 2016, and 2017.

Note: Please include vacation, non-work days, work days and partial days. If you were physically present in the United States for any part of a day (i.e., partial days), please count each partial day as one day. We recommend reviewing calendars, credit card statements, shopping receipts, etc.

6. Did you receive any other US source income during the period January 1, 2017 to December 31, 2017 that is required to be reported on a US federal income tax return? US source income that is required to be reported on a US federal income tax return includes, but is not limited to, US rental income, business income from US self-employment or as a contractor, income from a US partnership, US employment income or gains on sale of US real property.

17

Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

7. If you are married, please confirm the following for 2017:

1. Is your spouse currently a US citizen or were they born in the US?

2. Is your spouse a green card holder?

3. Did your spouse earn any US source income between January 1, 2017 and December 31, 2017?

4. Have you and your spouse ever both elected to file jointly file Form 1040 in prior years?

Individual investors will be notified immediately via pop-up message after completing Section D on their eligibility to prepare their US federal income tax returns through the Website.

Individual investors who are not eligible to use the Website to prepare their US federal income tax returns must still complete the Online Questionnaire to receive (by mail or email) the US Tax Slips (i.e., Form 8805 and Schedule K-1). You are not eligible to have your 2017 US federal income tax return prepared through this Website because you otherwise might have a US federal income tax filing requirement separate from receiving the 2017 capital gain dividend. Please consult your US tax advisor on the appropriate US tax filing in connection with your Form 8805 and Schedule K-1. Keep a copy of Form 8805 and Schedule K-1 for your records.

Non-US resident individual investors who are eligible to use the Website to prepare their US federal income tax returns will be prompted to complete the remaining questions in Section D of the Online Questionnaire, which requires the Unitholder to provide the following information:

1. Are you a resident of Canada, Mexico or South Korea or a US national?

2. Does your spouse have a US Social Security Number or US ITIN? If answered yes, please provide the following:

1. Spouse’s first and last name;

2. Spouse’s US Social Security Number or US ITIN.

3. What country did you claim residence for tax purposes during 2017?

4. Have you ever changed your (current or prior) US Visa type (non-immigrant status) or US immigrant status, if applicable? If answered yes, please indicate the date and the nature of the change.

5. If you are a Canadian resident and you do not commute to work in the US for more than 75% of your work days, provide a list of all dates you entered and left the US during 2017 (e.g. for short business trips or to visit family, vacation). The dates entered here must match to the total number of days provided earlier in the Online Questionnaire (see #5 on page 16).

6. Did you file a US federal income tax return for any prior year? If yes, please indicate the latest year and form number (i.e., Form 1040 or Form 1040NR) filed. For example, if you received a 2014 Form 1040NR after using the website in 2015, you would indicate this when answering this question on the Online Questionnaire.

18

Appendix A Checklist of Information Required to Complete the Online Questionnaire (con't)

Contact Information:

Sunstone and its service provider, KPMG, may need to contact you to clarify the information submitted through the Website. Sunstone and its service provider, KPMG, request that each Unitholder provide an email address and phone number to facilitate contact.

KPMG also requires the Unitholder’s email address or mailing address in order to send the completed copies of the US Tax package. Without a valid email or mailing address, a copy of the US Tax package will not be provided to you.

We highly recommend you select the email method to receive completed copies of your US Tax package. You will receive the package faster through email (compared to mail).

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Appendix B Instructions on How to Certify a Copy of Your Passport12

(Applicable Only to Investors that are Individuals)

Note: The IRS does not accept notarized (i.e., lawyer/notary notarization) copies of passports.

Instructions to obtain a certified copy from Passport Canada

The fastest way to obtain a certified copy of your Canadian passport is to apply in person at a Passport Canada office. Passport Canada currently charges a $45 fee for this service. Please complete the following steps:

1. Complete and sign a request for a certified true copy of Canadian travel document, Form PPTC 516 (see Appendix E for a copy of form) and submit your request in person at a Passport Canada office.

2. Passport Canada offices can be found on the following website:

http://www.cic.gc.ca/english/passport/map/map.asp

Processing time is up to 10 business days and may change depending on the volume of applications received. The original passport will remain with the Passport Canada office during the application process.

Instructions to obtain a certified copy from a US Consulate

For non-US persons residing outside of the US, a US consulate can certify passports for a fee of US$50 for each document. To take this option, please follow the steps below:

1. Call the US consulate closest to your area to confirm that they can certify a copy of your passport.

2. Go online and make an appointment with the US consulate to certify a copy of your passport (see link below for details – the online appointment link is the hyperlink under “Fees”, titled “American Citizen Services Scheduling System”).

3. Bring original passport and one photocopy (front and photo page) to the appointment with the proper payment in US dollars.

Details of this “authentication service” is in the following link:

https://travel.state.gov/content/travel/en/legal-considerations/judicial/authentication-of-documents/notarial-and-authentication-services-consular-officers.html

If you are currently residing outside of Canada you may still go to the US consulate closest to your area to have your copy of your passport certified.

Instructions to obtain a certified copy from a Certified Acceptance Agent

This service generally costs between $300 and $600. If you would like to certify your copy of your passport under this option, see the following IRS link for a list of Certified Acceptance Agents in your area: http://www.irs.gov/Individuals/Acceptance-Agent-Program.

12 Your passport must be valid for at least seven months from the time this Questionnaire is submitted. If your passport is not valid for

at least seven more months, you must renew your passport and get a certified copy.

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Appendix C Filing Instructions for Individual US Tax ID Application/Renewal

Form W-7 Filing Instructions

1. Sign and date the completed Form W-7. Attach with your Form W-7 the appropriate items listed in (a) below. Please attach item (b) to your completed Form W-7 only if you have previously applied for a US Social Security Number, but were not able to obtain one. For individuals renewing ITINs please note (c) for specific instructions:

1. Certified copy of your passport (See Appendix B). If you do not have a passport, please contact Sunstone at (604) 449-6402 for assistance.

The information on the passport must be consistent with the applicant’s information provided on Form W-7. For example, the name, date of birth and country(ies) of citizenship must be the same as on Form W-7.

2. If applicable, a letter or correspondence that you received if you applied for a US Social Security Number previously, but were not able to obtain one (i.e., a rejection letter).

3. To renew your ITIN, you must also include your previously assigned ITIN number on line 6f in Form W-7 to avoid delays in processing. The name under which you applied for your original ITIN must be included on line 6f. If your legal name has changed since the original assignment of your ITIN, you will need to attach documentation to Form W-7, such as your marriage certificate or a court order, to support your legal name change.

2. Mail Form W-7, a certified copy of your passport, and your completed US federal income tax return to (if you are not using a private delivery service, i.e., courier):

Internal Revenue Service ITIN Operation P.O. Box 149342 Austin, TX 78714-9342

To document the filing of the documents, we suggest that you obtain proof of mailing. Proof of mailing can be accomplished by sending the documents via private delivery service or registered mail (if outside of Canada) and keeping the receipt as evidence of filing.

If you are using a private delivery service (i.e., courier) to submit your Form W-7 and certified copy of your passport, use the following address:

Internal Revenue Service ITIN Operation Mail Stop 6090-AUSC 3651 S. Interregional, Hwy 35

Austin, TX 78741-0000

Please allow eight to ten weeks for the IRS to notify you of your ITIN. If you have not received any correspondence at the end of that time, you can call the IRS at 1-267-941-1000 to enquire about the status of your application. We recommend that you have copies of all documents submitted as you may be asked to fax in these documents while speaking to an IRS agent.

For individuals who have confirmed directly with Sunstone and are applying for their US Individual Tax Identification Number, we recommend filing your Form W-7 with your personal US tax return to minimize the risk of your application being rejected by the IRS.

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Appendix D Filing Instructions for Entity US Tax ID Application

Form SS-4 Filing Instructions

1. Please have your Form SS-4 signed and dated by:

1. The president, vice president or other principal officer if the applicant is a corporation;

2. A responsible and duly authorized member or officer having knowledge of its affairs if the applicant is a partnership; or

3. The fiduciary if the applicant is a trust or an estate.

2. You can receive your US Tax ID (i.e., Employer Identification Number) by telephone (non-US applicants) or online (US applicants) and use it immediately:

Non-US applicants: 1-267-941-1099 US applicants: https://sa.www4.irs.gov/modiein/individual/index.jsp

The person making the call must be authorized to sign the form. Please be ready to FAX your signed and completed Form SS-4, if requested. An IRS representative will provide you with a fax number.

An IRS representative will use the information from the Form SS-4 to establish your account and assign you an Employer Identification Number. Write the number you are given on the upper right corner of the form and sign and date it. Keep this copy for your records.

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Appendix E Form PPTC 516 – Request for Certified True Copy of Canadian Travel Document