PLAINS ALL AMERICAN PIPELINE, L.P.
(Exact Name of Registrant as Specified in its Charter)

333 Clay Street, Suite 1600
Houston, Texas 77002
(713) 646-4100
(Address, Including Zip Code, and Telephone Number, including Area Code, of Registrant's Principal Executive Offices)

Richard McGee
Executive Vice President, General Counsel and Secretary
333 Clay Street, Suite 1600
Houston, Texas 77002
(713) 646-4100
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copy to:
David P. Oelman
Alan Beck
Vinson & Elkins L.L.P.
First City Tower
1001 Fannin Street, Suite 2500
Houston, Texas 77002
(713) 758-2222

Approximate date of commencement of proposed sale to the public:
From time to time after the effective date of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box: o

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box: ý

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. o

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Title of Securities to be Registered	Amount to be Registered	Proposed Maximum Offering Price Per Unit	Proposed Maximum Aggregate Offering Price	Amount of Registration Fee




Common units representing limited partner interests	69,696,542(1)(2)	$18.65(3)	$1,299,840,508.30(3)	$161,830.14(3)

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. Securities may not be sold pursuant to this prospectus until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

This prospectus relates to up to 69,696,542 common units representing limited partner interests in us ("common units") issuable upon conversion of 69,696,542 Series A Convertible Preferred Units representing limited partnership interests in us ("Series A preferred units") that the selling unitholders named in this prospectus may from time to time, in one or more offerings, offer and sell. For a detailed discussion of the selling unitholders, please read "Selling Unitholders."

The selling unitholders may offer and sell these common units to or through one or more underwriters, dealers or agents, or directly to investors, in amounts, at prices and on terms to be determined by market conditions and other factors at the time of the offering. This prospectus describes only the general terms of these common units and the general manner of offering these common units by the selling unitholders. We may file one or more prospectus supplements that may describe the specific manner in which the selling unitholders will offer the common units and also may add, update or change information contained in this prospectus.

You should read this prospectus and any applicable prospectus supplement and the documents incorporated by reference herein or therein carefully before you invest in any of our common units. You should also read the documents we have referred you to in the "Where You Can Find More Information" section of this prospectus for information about us, including our financial statements.

Our common units are listed on the New York Stock Exchange ("NYSE") under the symbol "PAA."

Limited partnerships are inherently different than corporations, and investing in our common units involves a high degree of risk. You should carefully consider the risks relating to investing in our common units and each of the other risk factors described under "Risk Factors" on page 8 of this prospectus before you make an investment in our common units.

Neither the Securities and Exchange Commission (the "SEC") nor any state securities commission has approved or disapproved of the common units or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

In making your investment decision, you should rely only on the information contained or incorporated by reference in this prospectus. We have not authorized anyone to provide you with any other information. If anyone provides you with different or inconsistent information, you should not rely on it.

You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus. You should not assume that the information contained in the documents incorporated by reference in this prospectus is accurate as of any date other than the respective dates of those documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus is part of a registration statement on Form S-3 that we filed with the SEC utilizing a "shelf" registration process. Under this shelf registration process, the selling unitholders may over time, in one or more offerings, offer and sell up to 69,696,542 of our common units.

We may file one or more prospectus supplements that may describe the specific manner in which the selling unitholders will offer the common units and may also add, update or change information in this prospectus. If there is any inconsistency between the information in this prospectus and any prospectus supplement, you should rely on the information in such prospectus supplement. Before you invest in our common units, you should carefully read both this prospectus and any prospectus supplement, together with additional information described under the heading "Where You Can Find More Information," and any additional information you may need to make your investment decision.

We "incorporate by reference" information into this prospectus, which means that we disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, except for any information superseded by information contained expressly in this prospectus or any prospectus supplement, and the information we file later with the SEC will automatically supersede this information. You should not assume that the information in this prospectus is current as of any date other than the date on the front page of this prospectus, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of such document.

We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), including all such documents we may file with the SEC (excluding any information furnished pursuant to Item 2.02 or 7.01 of any Current Report on Form 8-K) after the initial filing date of the registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement and, following the effectiveness of the registration statement, until all offerings under the registration statement and this prospectus are completed:

You may request a copy of any document incorporated by reference in this prospectus and any exhibit specifically incorporated by reference in those documents, at no cost, by writing or telephoning us at the following address or phone number:

Plains All American Pipeline, L.P.
333 Clay Street, Suite 1600
Houston, Texas 77002
Attention: Corporate Secretary
Telephone: (713) 646-4100

Additionally, you may read and copy any documents filed by us at the SEC's public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-732-0330 for further information on its Public Reference Room. Our SEC filings are also available to the public from commercial document retrieval services and at the SEC's website www.sec.gov.

We also make available free of charge on our website at ir.paalp.com our Annual Reports on Form 10-K, our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K, and any amendments to those reports, as soon as reasonably practicable after we electronically file such material with the SEC. Information contained on our website is not incorporated by reference into this prospectus and you should not consider information contained on our website as part of this prospectus.

All statements included or incorporated by reference in this prospectus or the accompanying prospectus supplement, other than statements of historical fact, are forward-looking statements, including but not limited to statements incorporating the words "anticipate," "believe," "estimate," "expect," "plan," "intend" and "forecast," as well as similar expressions and statements regarding our business strategy, plans and objectives for future operations. The absence of such words, expressions or statements, however, does not mean that the statements are not forward-looking. Any such forward-looking statements reflect our current views with respect to future events, based on what we believe to be reasonable assumptions. Certain factors could cause actual results or outcomes to differ materially from the results or outcomes anticipated in the forward-looking statements. The most important of these factors include, but are not limited to:

Other factors described herein or incorporated by reference, or factors that are unknown or unpredictable, could also have a material adverse effect on future results. Please read "Risk Factors" beginning on page 8 of this prospectus and in Item 1A. "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2016 (File No. 001-14569), which is incorporated into this prospectus by reference. Except as required by applicable securities laws, we do not intend to update these forward-looking statements and information.

We are a Delaware limited partnership formed in 1998. Our operations are conducted directly and indirectly through our primary operating subsidiaries. We own and operate midstream energy infrastructure and provide logistics services for crude oil, NGL, natural gas and refined products.

We own an extensive network of pipeline transportation, terminalling, storage, and gathering assets in key crude oil and NGL producing basins and transportation corridors and at major market hubs in the United States and Canada. Our business activities are conducted through three operating segments: Transportation, Facilities and Supply and Logistics.

For purposes of this prospectus, unless the context clearly indicates otherwise, "Partnership," "Plains," "PAA," "we," "us," "our," "ours" and similar terms refer to Plains All American Pipeline, L.P. and its subsidiaries. References to our "general partner," as the context requires, include any or all of PAA GP Holdings LLC ("PAGP GP"), Plains GP Holdings, L.P. ("PAGP"), PAA GP LLC ("PAA GP"), Plains AAP, L.P. ("AAP") and Plains All American GP LLC ("GP LLC").

Consistent with our business strategy, we are continuously engaged in the evaluation of potential acquisitions, joint ventures and capital projects. As a part of these efforts, we often engage in discussions with potential sellers or other parties regarding the possible purchase of or investment in assets and operations that are strategic and complementary to our existing operations. In addition, we have in the past evaluated and pursued, and intend in the future to evaluate and pursue, the acquisition of or investment in other energy-related assets that have characteristics and opportunities similar to our existing business lines and enable us to leverage our assets, knowledge and skill sets. Such efforts may involve participation by us in processes that have been made public and involve a number of potential buyers or investors, commonly referred to as "auction" processes, as well as situations in which we believe we are the only party or one of a limited number of parties who are in negotiations with the potential seller or other party. These acquisition and investment efforts often involve assets which, if acquired or constructed, could have a material effect on our financial condition and results of operations.

From time to time, we may also (i) sell assets that we regard as non-core or that we believe might be a better fit with the business or assets of a third-party buyer or (ii) sell partial interests in assets to strategic joint venture partners, in each case to optimize our asset portfolio and strengthen our balance sheet and leverage metrics. With respect to a potential divestiture, we may conduct an auction process or may negotiate a transaction with one or a limited number of potential buyers.

We typically do not announce a transaction until after we have executed a definitive agreement. However, in certain cases in order to protect our business interests or for other reasons, we may defer public announcement of a transaction until closing or a later date. Past experience has demonstrated that discussions and negotiations regarding a potential transaction can advance or terminate in a short period of time. Moreover, the closing of any transaction for which we have entered into a definitive agreement may be subject to customary and other closing conditions, which may not ultimately be satisfied or waived. Accordingly, we can give no assurance that our current or future acquisition or investment efforts will be successful or that our strategic asset divestitures will be completed. Although we expect the acquisitions and investments we make to be accretive in the long term, we can provide no assurance that our expectations will ultimately be realized.

Our principal executive offices are located at 333 Clay Street, Suite 1600, Houston, Texas 77002 and our telephone number is (713) 646-4100. We maintain a website at www.plainsallamerican.com that provides information about our business and operations. We make our periodic and current reports and other information filed with or furnished to the SEC available, free of charge, through our website, as soon as reasonably practicable after those reports and other information are electronically filed with or furnished to the SEC. Information contained on or available through our website or any other website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus.

For additional information about us please refer to the documents set forth under "Where You Can Find More Information" in this prospectus, including our Annual Report on Form 10-K for the year ended December 31, 2016 and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2017, each of which is incorporated by reference herein.

An investment in our common units involves a high degree of risk. Before you invest in our common units, you should carefully consider the risk factors included in Item 1A. "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2016 (File No. 001-14569), which is incorporated into this prospectus by reference, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our common units. If any of these risks were to occur, our business, financial condition or results of operations could be materially adversely affected. In such case, the trading price of our common units could decline and you could lose all or part of your investment. When we offer and sell any securities pursuant to a prospectus supplement, we may include additional risk factors relevant to such securities in the prospectus supplement.

We will not receive any of the proceeds from the sale of common units by the selling unitholders in any offering. We will cause the selling unitholders to pay certain expenses, pro rata, including underwriting discounts and commissions, associated with the sale of common units by the selling unitholder.

Please see our registration statement on Form 8-A/A filed on November 16, 2016 (together with any amendments thereto and the other documents incorporated by reference therein), which is incorporated by reference herein, for a description of our common units, our cash distribution policy and our partnership agreement.

This section summarizes the material U.S. federal income tax consequences that may be relevant to prospective unitholders and is based upon current provisions of the Internal Revenue Code of 1986, as amended (the "Code"), existing and proposed Treasury regulations thereunder (the "Treasury Regulations"), and current administrative rulings and court decisions, all of which are subject to change. Changes in these authorities may cause the federal income tax consequences to a prospective unitholder to vary substantially from those described below, possibly on a retroactive basis. Unless the context otherwise requires, references in this section to "we" or "us" are references to Plains All American Pipeline, L.P. and its subsidiaries.

Legal conclusions contained in this section, unless otherwise noted, are the opinion of Vinson & Elkins L.L.P. and are based on the accuracy of representations made by us to them for this purpose. However, this section does not address all federal income tax matters that may affect us or our unitholders, such as the application of the alternative minimum tax. This section also does not address local taxes, state taxes, non-U.S. taxes, or other taxes that may be applicable, except to the limited extent that such tax considerations are addressed below under "—Administrative Matters—State, Local and Other Tax Considerations." Furthermore, this section focuses on unitholders who are individual citizens or residents of the United States (for federal income tax purposes), who have the U.S. dollar as their functional currency, who use the calendar year as their taxable year, who purchase units in this offering, who do not materially participate in the conduct of our business activities and who hold such units as capital assets (typically, property that is held for investment). This section has limited applicability to corporations (including other entities treated as corporations for federal income tax purposes), partnerships (including other entities treated as partnerships for federal income tax purposes), estates, trusts, non-resident aliens or other unitholders subject to specialized tax treatment, such as tax-exempt entities, non-U.S. persons, individual retirement accounts ("IRAs"), employee benefit plans, real estate investment trusts or mutual funds. Accordingly, we encourage each prospective unitholder to consult the unitholder's own tax advisor in analyzing the federal, state, local and non-U.S. tax consequences particular to that unitholder resulting from ownership or disposition of units and potential changes in applicable tax laws.

No ruling has been or will be requested from the IRS with respect to the partnership's classification as a partnership for federal income tax purposes or as to the classification of our partnership and limited liability company operating subsidiaries. We will rely on the opinions and advice of Vinson & Elkins L.L.P. with respect to the matters described herein. An opinion of counsel represents only that counsel's best legal judgment and does not bind the Internal Revenue Service (the "IRS") or a court. Accordingly, the opinions and statements made herein may not be sustained by a court if contested by the IRS. Any such contest of the matters described herein may materially and adversely impact the market for our units and the prices at which our units trade. In addition, our costs of any contest with the IRS will be borne indirectly by our unitholders and our general partner because the costs will reduce our cash available for distribution. Furthermore, the tax consequences of an investment in us may be significantly modified by future legislative or administrative changes or court decisions, which may be retroactively applied.

For the reasons described below, Vinson & Elkins L.L.P. has not rendered an opinion with respect to the following federal income tax issues: (1) the treatment of a unitholder whose units are the subject of a securities loan (e.g., a loan to a short seller to cover a short sale of units) (please read "—Tax Consequences of Unit Ownership—Treatment of Securities Loans"); (2) whether our monthly convention for allocating taxable income and losses is permitted by existing Treasury Regulations (please read "—Disposition of Units—Allocations Between Transferors and Transferees"); (3) whether our method for taking into account Section 743 adjustments is sustainable in certain cases (please read "—Tax Consequences of Unit Ownership—Section 754 Election" and "—Disposition of Units—Uniformity of Units") and (4) whether our allocations of income, gain, loss and deduction will be given

effect for U.S. federal income tax purposes (please read "—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction").

We expect to be treated as a partnership for U.S. federal income tax purposes and, therefore, subject to the discussion below under "—Administrative Matters—Information Returns and Audit Procedures", generally will not be liable for entity-level federal income taxes. Instead, as described below, each of our unitholders will take into account its respective share of our items of income, gain, loss and deduction in computing its federal income tax liability as if the unitholder had earned such income directly, even if we make no cash distributions to the unitholder. Distributions we make to a unitholder will not give rise to income or gain taxable to such unitholder, unless the amount of cash distributed exceeds the unitholder's adjusted tax basis in its units. Please read "—Tax Consequences of Unit Ownership—Treatment of Distributions" and "—Disposition of Units").

Section 7704 of the Code provides that a publicly traded partnership will be treated as a corporation for federal income tax purposes. However, if 90% or more of a partnership's gross income for every taxable year it is publicly traded consists of "qualifying income," the partnership may continue to be treated as a partnership for federal income tax purposes (the "Qualifying Income Exception"). Qualifying income includes (i) interest, (ii) dividends, (iii) real property rents within the meaning of Section 856(d) of the Code, as modified by Section 7704(d)(3) of the Code, (iv) gains from the sale or other disposition of real property, (v) income and gains derived from the exploration, development, mining or production, processing, refining, transportation (including pipelines transporting gas, oil, or products thereof) or the marketing of any "mineral or natural resource", and (vi) gains from the sale or disposition of a capital asset (or property described in Section 1231(b) of the Code) held for the production of qualifying income. We estimate that less than 5 percent of our current gross income is not qualifying income; however, this estimate could change from time to time.

Vinson & Elkins L.L.P. is of the opinion that we will be treated as a partnership for federal income tax purposes and each of our operating subsidiaries, other than those that have been identified as corporations to Vinson & Elkins L.L.P., will be treated as a partnership or will be disregarded as an entity separate from us. In rendering its opinion, Vinson & Elkins L.L.P. has relied on the factual representations made by us and our general partner, including, without limitation:

If we fail to meet the Qualifying Income Exception, other than a failure that is determined by the IRS to be inadvertent and that is cured within a reasonable time after discovery (in which case the IRS may also require us to make adjustments with respect to our unitholders or pay other amounts), we will

be treated as transferring all of our assets, subject to all of our liabilities, to a newly formed corporation, on the first day of the year in which we fail to meet the Qualifying Income Exception, in return for stock in that corporation and then as distributing that stock to our unitholders in liquidation. This deemed contribution and liquidation should not result in the recognition of taxable income by our unitholders or us so long as the aggregate amount of our liabilities does not exceed the adjusted tax basis of our assets. Thereafter, we would be treated as an association taxable as a corporation for federal income tax purposes.

The present federal income tax treatment of publicly traded partnerships, including us, or an investment in our units may be modified by administrative or legislative action or judicial interpretation at any time. From time to time, members of the U.S. Congress propose and consider substantive changes to the existing federal income tax laws that affect publicly traded partnerships. One such legislative proposal would have eliminated the Qualifying Income Exception upon which we rely for our treatment as a partnership for federal income tax purposes.

In addition, on January 24, 2017, final regulations regarding which activities give rise to qualifying income (the "Final Regulations") were published in the Federal Register. The Final Regulations are effective as of January 19, 2017, and apply to taxable years beginning on or after January 19, 2017. We do not believe the Final Regulations affect our ability to qualify as a publicly traded partnership.

It is possible that a change in law could affect us and may be applied retroactively. Any such changes could negatively impact the value of an investment in our units. If for any reason we are taxable as a corporation in any taxable year, our items of income, gain, loss and deduction would be taken into account by us in determining the amount of our liability for federal income tax, rather than being passed through to our unitholders.

At the state level, several states have been evaluating ways to subject partnerships to entity-level taxation through the imposition of state income, franchise, or other forms of taxation. Imposition of a similar tax on us in the jurisdictions in which we operate or in other jurisdictions to which we may expand could substantially reduce our cash available for distribution to our unitholders.

Our partnership agreement provides that if a law is enacted or existing law is modified or interpreted in a manner that subjects us to taxation as a corporation or otherwise subjects us to entity-level taxation for federal, state or local income tax purposes, the minimum quarterly distribution amount and the target distribution amounts may be adjusted to reflect the impact of that law on us. Our taxation as a corporation would materially reduce the cash available for distribution to unitholders and thus would likely substantially reduce the value of our units. Any distribution made to a unitholder at a time we are treated as a corporation would be (i) a taxable dividend to the extent of our current or accumulated earnings and profits, then (ii) a nontaxable return of capital to the extent of the unitholder's adjusted tax basis in its units (determined separately for each unit), and thereafter (iii) taxable capital gain.

The remainder of this discussion is based on the opinion of Vinson & Elkins L.L.P. that we will be treated as a partnership for federal income tax purposes.

Unitholders of the partnership who are admitted as limited partners of the partnership and unitholders whose units are held in street name or by a nominee and who have the right to direct the nominee in the exercise of all substantive rights attendant to the ownership of their units will be treated as partners of the partnership for federal income tax purposes.

As there is no direct or indirect controlling authority addressing assignees of units who are entitled to execute and deliver transfer applications and thereby become entitled to direct the exercise of attendant rights, but who fail to execute and deliver transfer applications, Vinson & Elkins L.L.P.'s opinion does not extend to these persons. Furthermore, a purchaser or other transferee of units who does not execute and deliver a transfer application may not receive some federal income tax information or reports furnished to record holders of units unless the units are held in a nominee or street name account and the nominee or broker has executed and delivered a transfer application for those units.

In addition, a beneficial owner of units whose units have been transferred to a short seller to complete a short sale would appear to lose status as a partner with respect to such units for federal income tax purposes. Please read "—Tax Consequences of Unit Ownership—Treatment of Securities Loans."

Income, gain, deductions or losses would not appear to be reportable by a unitholder who is not a partner for federal income tax purposes, and any cash distributions received by a unitholder who is not a partner for federal income tax purposes would therefore appear to be fully taxable as ordinary income. A unitholder who is not treated as a partner in us as described above is urged to consult its own tax advisors with respect to the tax consequences applicable to such unitholder under its particular circumstances.

Subject to the discussion below under "—Entity-Level Collections of Unitholder Taxes" and "—Administrative Matters—Information Returns and Audit Procedures" with respect to payments we may be required to make on behalf of our unitholders, and aside from any taxes paid by a corporate subsidiary, we will not pay any federal income tax. Rather, each unitholder will be required to report on its federal income tax return each year its share of our income, gains, losses and deductions for our taxable year or years ending with or within its taxable year . Consequently, we may allocate income to a unitholder even if that unitholder has not received a cash distribution.

A unitholder's tax basis in its units initially will be the amount paid for those units increased by the unitholder's initial allocable share of our liabilities. That basis generally will be (i) increased by the unitholder's share of our income and any increases in such unitholder's share of our liabilities, and (ii) decreased, but not below zero, by the amount of all distributions to the unitholder, the unitholder's share of our losses, and any decreases in its share of our liabilities. The IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all of those interests.

Distributions made by us to a unitholder generally will not be taxable to the unitholder, unless such distributions are of cash or marketable securities that are treated as cash and exceed the unitholder's tax basis in its units, in which case the unitholder generally will recognize gain taxable in the manner described below under "—Disposition of Units."

Any reduction in a unitholder's share of our "nonrecourse liabilities" (liabilities for which no partner bears the economic risk of loss) will be treated as a distribution by us of cash to that unitholder. A decrease in a unitholder's percentage interest in us because of our issuance of additional units may decrease such unitholder's share of our nonrecourse liabilities. For purposes of the foregoing, a unitholder's share of our nonrecourse liabilities generally will be based upon such unitholder's share of the unrealized appreciation (or depreciation) in our assets, to the extent thereof, with any excess

nonrecourse liabilities allocated based on the unitholder's share of our profits. Please read "—Disposition of Units."

A non-pro rata distribution of money or property (including a deemed distribution as a result of the reallocation of our nonrecourse liabilities described above) may cause a unitholder to recognize ordinary income if the distribution reduces the unitholder's share of our "unrealized receivables," including depreciation recapture and substantially appreciated "inventory items," both as defined in Section 751 of the Code ("Section 751 Assets"). To the extent of such reduction, the unitholder would be deemed to receive its proportionate share of the Section 751 Assets and exchange such assets with us in return for a portion of the non-pro rata distribution. This deemed exchange will generally result in the unitholder's recognition of ordinary income in an amount equal to the excess of (1) the non-pro rata portion of that distribution over (2) the unitholder's tax basis (typically zero) in the Section 751 Assets deemed to be relinquished in the exchange.

A unitholder may not be entitled to deduct the full amount of loss we allocate to it because its share of our losses will be limited to the lesser of (i) the unitholder's adjusted tax basis in its units, and (ii) in the case of a unitholder that is an individual, estate, trust or certain types of closely-held corporations, the amount for which the unitholder is considered to be "at risk" with respect to our activities. A unitholder will be at risk to the extent of its adjusted tax basis in its units, reduced by (1) any portion of that basis attributable to the unitholder's share of our nonrecourse liabilities, (2) any portion of that basis representing amounts otherwise protected against loss because of a guarantee, stop loss agreement or similar arrangement, and (3) any amount of money the unitholder borrows to acquire or hold its units, if the lender of those borrowed funds owns an interest in us, is related to another unitholder or can look only to the units for repayment. A unitholder subject to the at risk limitation must recapture losses deducted in previous years to the extent that distributions (including distributions deemed to result from a reduction in a unitholder's share of nonrecourse liabilities) cause the unitholder's at risk amount to be less than zero at the end of any taxable year.

Losses disallowed to a unitholder or recaptured as a result of the basis or at risk limitations will carry forward and will be allowable as a deduction in a later year to the extent that the unitholder's adjusted tax basis or at risk amount, whichever is the limiting factor, is subsequently increased. Upon a taxable disposition of units, any gain recognized by a unitholder can be offset by losses that were previously suspended by the at risk limitation but not losses suspended by the basis limitation. Any loss previously suspended by the at risk limitation in excess of that gain can no longer be used, and will not be available to offset a unitholder's salary or active business income.

In addition to the basis and at risk limitations, a passive activity loss limitation limits the deductibility of losses incurred by individuals, estates, trusts, some closely-held corporations and personal service corporations from "passive activities" (such as, trade or business activities in which the taxpayer does not materially participate). The passive loss limitations are applied separately with respect to each publicly traded partnership. Consequently, any passive losses we generate will be available to offset only passive income generated by us. For this purpose, any income from a guaranteed payment for the use of capital generally will not be treated as passive income. As a result, holders of certain of our preferred units treated as receiving guaranteed payment for the use of capital generally may not be able to offset that income with losses or deductions allocated to our common units. Passive losses that exceed a unitholder's share of passive income we generate may be deducted in full when a unitholder disposes of all of its units in a fully taxable transaction with an unrelated party. The passive loss rules are applied after other applicable limitations on deductions, including the at risk and basis limitations.

The deductibility of a non-corporate taxpayer's "investment interest expense" is generally limited to the amount of that taxpayer's "net investment income." Investment interest expense includes:

The computation of a unitholder's investment interest expense will take into account interest on any margin account borrowing or other loan incurred to purchase or carry a unit. Net investment income includes gross income from property held for investment and amounts treated as portfolio income under the passive loss rules, less deductible expenses, other than interest, directly connected with the production of investment income. Net investment income does not include qualified dividend income (if applicable) or gains attributable to the disposition of property held for investment. A unitholder's share of a publicly traded partnership's portfolio income and, according to the IRS, net passive income will be treated as investment income for purposes of the investment interest expense limitation.

If we are required or elect under applicable law to pay any federal, state, local or non-U.S. tax on behalf of any current or former unitholder or our general partner, our partnership agreement authorizes us to treat the payment as a distribution of cash to the relevant unitholder or general partner. Where the tax is payable on behalf of all unitholders or we cannot determine the specific unitholder on whose behalf the tax is payable, our partnership agreement authorizes us to treat the payment as a distribution to all current unitholders. Payments by us as described above could give rise to an overpayment of tax on behalf of a unitholder, in which event the unitholder may be entitled to claim a refund of the overpayment amount. Please read "—Administrative Matters—Information Returns and Audit Procedures." Each unitholder is urged to consult its tax advisor to determine the consequences to them of any tax payment we make on its behalf.

Except as described below, our items of income, gain, loss and deduction will be allocated among our unitholders in accordance with their percentage interests in us. Specified items of our income, gain, loss and deduction will be allocated under Section 704(c) of the Code (or the principles of Section 704(c) of the Code) to account for any difference between the adjusted tax basis and fair market value of our assets at the time such assets are contributed to us and at the time of any subsequent offering of our units (a "Book-Tax Disparity"). As a result, the federal income tax burden associated with any Book-Tax Disparity immediately prior to an offering will be borne by our partners holding interests in us prior to such offering. In addition, items of recapture income will be specially allocated to the extent possible (subject to the limitations described above) to the unitholder who was allocated the deduction giving rise to that recapture income in order to minimize the recognition of ordinary income by other unitholders.

An allocation of items of our income, gain, loss or deduction, other than an allocation required by the Code to eliminate a Book-Tax Disparity, will be given effect for federal income tax purposes in determining a unitholder's share of an item of income, gain, loss or deduction only if the allocation has "substantial economic effect." In any other case, a unitholder's share of an item will be determined on the basis of the unitholder's interest in us, which will be determined by taking into account all the facts and circumstances, including (i) the unitholder's relative contributions to us, (ii) the interests of all the

partners in profits and losses, (iii) the interest of all the partners in cash flow and (iv) the rights of all the partners to distributions of capital upon liquidation. Our allocations and liquidation provisions are designed in a way to give effect to our allocations, except to the extent required to achieve parity among the preferred units.

A unitholder whose units are the subject of a securities loan (for example, a loan to a "short seller" to cover a short sale of units) may be treated as having disposed of those units. If so, such unitholder would no longer be treated for tax purposes as a partner with respect to those units during the period of the loan and may recognize gain or loss as a result of such deemed disposition. As a result, during this period (i) any of our income, gain, loss or deduction allocated to those units would not be reportable by the lending unitholder, and (ii) any cash distributions received by the lending unitholder as to those units may be treated as ordinary taxable income.

Due to a lack of controlling authority, Vinson & Elkins L.L.P. has not rendered an opinion regarding the tax treatment of a unitholder that enters into a securities loan with respect to its units. A unitholder desiring to assure its status as a partner and avoid the risk of income recognition from a loan of its units is urged to modify any applicable brokerage account agreements to prohibit its brokers from borrowing and lending its units. The IRS has announced that it is studying issues relating to the tax treatment of short sales of partnership interests. Please read "—Disposition of Units—Recognition of Gain or Loss."

Under current law, the highest marginal federal income tax rates for individuals applicable to ordinary income and long-term capital gains (generally, gains from the sale or exchange of certain investment assets held for more than one year) are 39.6% and 20%, respectively. These rates are subject to change by new legislation at any time.

In addition, a 3.8% net investment income tax applies to certain net investment income earned by individuals, estates, and trusts. For these purposes, net investment income generally includes a unitholder's allocable share of our income and gain realized by a unitholder from a sale of units. In the case of an individual, the tax will be imposed on the lesser of (i) the unitholder's net investment income from all investments, or (ii) the amount by which the unitholder's modified adjusted gross income exceeds $250,000 (if the unitholder is married and filing jointly or a surviving spouse), $125,000 (if married filing separately) or $200,000 (if the unitholder is unmarried or in any other case). In the case of an estate or trust, the tax will be imposed on the lesser of (i) undistributed net investment income, or (ii) the excess adjusted gross income over the dollar amount at which the highest income tax bracket applicable to an estate or trust begins.

We have made the election permitted by Section 754 of the Code that permits us to adjust the tax bases in our assets as to specific purchasers of our units under Section 743(b) of the Code to reflect the unit purchase price upon subsequent purchases of units. That election is irrevocable without the consent of the IRS. The Section 743(b) adjustment separately applies to unitholder who purchases units from another unitholder based upon the values and adjusted tax basis of each of our assets at the time of the relevant purchase, and the adjustment will reflect the purchase price paid. The Section 743(b) adjustment does not apply to a person who purchases units directly from us. For purposes of this discussion, a unitholder's basis in our assets will be considered to have two components: (1) its share of the tax basis in our assets as to all unitholders and (2) its Section 743(b) adjustment to that tax basis (which may be positive or negative).

Under our partnership agreement, we are authorized to take a position to preserve the uniformity of units even if that position is not consistent with applicable Treasury Regulations. A literal application of Treasury Regulations governing a 743(b) adjustment attributable to properties depreciable under Section 167 of the Code may give rise to differences in the taxation of unitholders purchasing units from us and unitholders purchasing from other unitholders. If we have any such properties, we intend to adopt methods employed by other publicly traded partnerships to preserve the uniformity of units, even if inconsistent with existing Treasury Regulations, and Vinson & Elkins L.L.P. has not opined on the validity of this approach. Please read "—Disposition of Units—Uniformity of Units."

The IRS may challenge the positions we adopt with respect to depreciating or amortizing the Section 743(b) adjustment to preserve the uniformity of units due to lack of controlling authority. Because a unitholder's adjusted tax basis for its units is reduced by its share of our items of deduction or loss, any position we take that understates deductions will overstate a unitholder's basis in its units, and may cause the unitholder to understate gain or overstate loss on any sale of such units. Please read "—Disposition of Units—Recognition of Gain or Loss." If a challenge to such treatment were sustained, the gain from the sale of units may be increased without the benefit of additional deductions.

The calculations involved in the Section 754 election are complex and are made on the basis of assumptions as to the value of our assets and other matters. The IRS could seek to reallocate some or all of any Section 743(b) adjustment we allocated to our assets subject to depreciation to goodwill or nondepreciable assets. Goodwill, as an intangible asset, is amortizable over a longer period of time or under a less accelerated method than certain of our tangible assets. We cannot assure any unitholder that the determinations we make will not be successfully challenged by the IRS or that the resulting deductions will not be reduced or disallowed altogether. Should the IRS require a different tax basis adjustment to be made, and should, in our opinion, the expense of compliance exceed the benefit of the election, we may seek permission from the IRS to revoke our Section 754 election. If permission is granted, a subsequent purchaser of units may be allocated more income than it would have been allocated had the election not been revoked.

We will use the year ending December 31 as our taxable year and the accrual method of accounting for federal income tax purposes. Each unitholder will be required to include in its tax return its share of our income, gain, loss and deduction for each taxable year ending within or with its taxable year. In addition, a unitholder who has a taxable year ending on a date other than December 31 and who disposes of all of its units following the close of our taxable year but before the close of its taxable year must include its share of our income, gain, loss and deduction in income for its taxable year, with the result that it will be required to include in income for its taxable year its share of more than twelve months of our income, gain, loss and deduction. Please read "—Disposition of Units—Allocations Between Transferors and Transferees."

The tax basis of each of our assets will be used for purposes of computing depreciation and cost recovery deductions and, ultimately, gain or loss on the disposition of these assets. If we dispose of depreciable property by sale, foreclosure or otherwise, all or a portion of any gain, determined by reference to the amount of depreciation and deductions previously taken, may be subject to the recapture rules and taxed as ordinary income rather than capital gain. Similarly, a unitholder who has taken cost recovery or depreciation deductions with respect to property we own will likely be required to recapture some or all of those deductions as ordinary income upon a sale of its interest in us. Please read "—Tax Consequences of Unit Ownership—Allocation of Income, Gain, Loss and Deduction" and "—Disposition of Units—Recognition of Gain or Loss."

The costs we incur in offering and selling our units (called "syndication expenses") must be capitalized and cannot be deducted currently, ratably or upon our termination. While there are uncertainties regarding the classification of certain costs as organization expenses, which may be amortized by us, and as syndication expenses, which may not be amortized by us, the underwriting discounts and commissions we incur will be treated as syndication expenses. Please read "—Disposition of Units—Recognition of Gain or Loss."

The federal income tax consequences of the ownership and disposition of units will depend in part on our estimates of the relative fair market values and the tax basis of each of our assets. Although we may from time to time consult with professional appraisers regarding valuation matters, we will make many of the relative fair market value estimates ourselves. These estimates and determinations of tax basis are subject to challenge and will not be binding on the IRS or the courts. If the estimates of fair market value or tax basis are later found to be incorrect, the character and amount of items of income, gain, loss or deduction previously reported by a unitholder could change, and such unitholder could be required to adjust its tax liability for prior years and incur interest and penalties with respect to those adjustments.

A unitholder will be required to recognize gain or loss on a sale or exchange of a unit equal to the difference, if any, between the unitholder's amount realized and the adjusted tax basis in the unit sold. A unitholder's amount realized generally will equal the sum of the cash and the fair market value of other property it receives plus its share of our nonrecourse liabilities with respect to the unit sold or exchanged. Because the amount realized includes a unitholder's share of our nonrecourse liabilities, the gain recognized on the sale or exchange of a unit could result in a tax liability in excess of any cash received from the sale or exchange.

Except as noted below, gain or loss recognized by a unitholder on the sale or exchange of a unit held for more than one year generally will be taxable as long-term capital gain or loss. However, gain or loss recognized on the disposition of units will be separately computed and taxed as ordinary income or loss under Section 751 of the Code to the extent attributable to Section 751 Assets, such as depreciation recapture and our "inventory items," regardless of whether such inventory item is substantially appreciated in value. Ordinary income attributable to Section 751 Assets may exceed net taxable gain realized on the sale or exchange of a unit and may be recognized even if there is a net taxable loss realized on the sale or exchange of a unit. Thus, a unitholder may recognize both ordinary income and capital gain or loss upon a sale or exchange of a unit. Net capital loss may offset capital gains and, in the case of individuals, up to $3,000 of ordinary income per year.

For purposes of calculating gain or loss on the sale or exchange of a unit, the unitholder's adjusted tax basis will be adjusted by its allocable share of our income or loss in respect of its unit for the year of the sale. Furthermore, as described above, the IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all those interests. Upon a sale or other disposition of less than all of those interests, a portion of that tax basis must be allocated to the interests sold using an "equitable apportionment" method, which generally means that the tax basis allocated to the interest sold equals an amount that bears the same relation to the partner's tax basis in its entire interest in the partnership as the value of the interest sold bears to the value of the partner's entire interest in the partnership.

Treasury Regulations under Section 1223 of the Code allow a selling unitholder who can identify units transferred with an ascertainable holding period to elect to use the actual holding period of the

units transferred. Thus, according to the ruling discussed in the paragraph above, a unitholder will be unable to select high or low basis units to sell or exchange as would be the case with corporate stock, but, according to the Treasury Regulations, such unitholder may designate specific units sold for purposes of determining the holding period of the units transferred. A unitholder electing to use the actual holding period of any unit transferred must consistently use that identification method for all subsequent sales or exchanges of our units. A unitholder considering the purchase of additional units or a sale or exchange of units purchased in separate transactions is urged to consult its tax advisor as to the possible consequences of this ruling and application of the Treasury Regulations.

Specific provisions of the Code affect the taxation of some financial products and securities, including partnership interests, by treating a taxpayer as having sold an "appreciated" financial position, including a partnership interest with respect to which gain would be recognized if it were sold, assigned or terminated at its fair market value, in the event the taxpayer or a related person enters into:

Moreover, if a taxpayer has previously entered into a short sale, an offsetting notional principal contract or a futures or forward contract with respect to the partnership interest, the taxpayer will be treated as having sold that position if the taxpayer or a related person then acquires the partnership interest or substantially identical property. The Secretary of the Treasury is authorized to issue Treasury Regulations that treat a taxpayer that enters into transactions or positions that have substantially the same effect as the preceding transactions as having constructively sold the financial position. Please read "—Tax Consequences of Unit Ownership—Treatment of Securities Loans."

In general, our taxable income or loss will be determined annually, will be prorated on a monthly basis and will be subsequently apportioned among the unitholders in proportion to the number of units owned by each of them as of the opening of the applicable exchange on the first business day of the month (the "Allocation Date"). Nevertheless, we allocate certain deductions for depreciation of capital additions based upon the date the underlying property is placed in service, and gain or loss realized on a sale or other disposition of our assets or, in the discretion of the general partner, any other extraordinary item of income, gain, loss or deduction will be allocated among the unitholders on the Allocation Date in the month in which such income, gain, loss or deduction is recognized. As a result, a unitholder transferring units may be allocated income, gain, loss and deduction realized after the date of transfer.

Although simplifying conventions are contemplated by the Code and most publicly traded partnerships use similar simplifying conventions, existing Treasury Regulations do not specifically authorize the use of the proration method we have adopted. Accordingly, Vinson & Elkins L.L.P. is unable to opine on the validity of this method of allocating income and deductions between transferee and transferor unitholders. If the IRS determines that this method is not allowed under the Treasury Regulations our taxable income or losses could be reallocated among our unitholders. Under our partnership agreement, we are authorized to revise our method of allocation between transferee and transferor unitholders, as well as among unitholders whose interests vary during a taxable year, to conform to a method permitted under the Treasury Regulations.

A unitholder who disposes of units prior to the record date set for a cash distribution for that quarter will be allocated items of our income, gain, loss and deduction attributable to the month of disposition but will not be entitled to receive a cash distribution for that period.

A unitholder who sells or exchanges any of its units is generally required to notify us in writing of that transaction within 30 days after the transaction (or, if earlier, January 15 of the year following the transaction in the case of a seller). Upon receiving such notifications, we are required to notify the IRS of that transaction and to furnish specified information to the transferor and transferee. Failure to notify us of a transfer of units may, in some cases, lead to the imposition of penalties. However, these reporting requirements do not apply to a sale by an individual who is a citizen of the United States and who effects the sale or exchange through a broker who will satisfy such requirements.

We will be considered to have technically terminated our partnership for federal income tax purposes upon the sale or exchange of 50% or more of the total interests in our capital and profits within a twelve-month period. For purposes of measuring whether the 50% threshold is reached, multiple sales of the same unit are counted only once. A technical termination results in the closing of our taxable year for all unitholders. In the case of a unitholder reporting on a taxable year other than the calendar year, the closing of our taxable year may result in more than twelve months of our taxable income or loss being includable in such unitholder's taxable income for the year of termination.

A technical termination occurring on a date other than December 31 would require that we file two tax returns for one fiscal year, thereby increasing our administration and tax preparation costs. However, pursuant to an IRS relief procedure, the IRS may allow a technically terminated partnership to provide a single Schedule K-1 for the calendar year in which a termination occurs. Following a technical termination, we would be required to make new tax elections, including a new election under Section 754 of the Code, and the termination would result in a deferral of our deductions for depreciation and thus may increase the taxable income allocable to our unitholders. A technical termination could also result in penalties if we were unable to determine that the technical termination had occurred. Moreover, a technical termination may either accelerate the application of, or subject us to, any tax legislation enacted before the technical termination that would not otherwise have been applied to us as a continuing partnership as opposed to a terminating partnership.

Because we cannot match transferors and transferees of units and for other reasons, we must maintain uniformity of the economic and tax characteristics of the units to a purchaser of these units. As a result of the need to preserve uniformity, we may be unable to completely comply with a number of federal income tax requirements. Any non-uniformity could have a negative impact on the value of our units. Please read "—Tax Consequences of Unit Ownership—Section 754 Election."

Our partnership agreement permits our general partner to take positions in filing our tax returns that preserve the uniformity of our units. These positions may include reducing the depreciation, amortization or loss deductions to which a unitholder would otherwise be entitled or reporting a slower amortization of Section 743(b) adjustments for some unitholders than that to which they would otherwise be entitled. Vinson & Elkins L.L.P. is unable to opine as to the validity of such filing positions.

A unitholder's adjusted tax basis in units is reduced by its share of our deductions (whether or not such deductions were claimed on an individual income tax return) so that any position that we take that understates deductions will overstate the unitholder's basis in its units, and may cause the unitholder to understate gain or overstate loss on any sale of such units. Please read "—Disposition of Units—Recognition of Gain or Loss" and "—Tax Consequences of Unit Ownership—Section 754 Election" above. The IRS may challenge one or more of any positions we take to preserve the uniformity of units. If such a challenge were sustained, the uniformity of units might be affected, and,

under some circumstances, the gain from the sale of units might be increased without the benefit of additional deductions.

Ownership of units by employee benefit plans and other tax-exempt organizations, as well as by non-resident alien individuals, non-U.S. corporations and other non-U.S. persons (collectively, "Non-U.S. Unitholders") raises issues unique to those investors and, as described below, may have substantially adverse tax consequences to them. Each prospective unitholder that is a tax-exempt entity or a Non-U.S. Unitholder should consult its tax advisors before investing in our units.

Employee benefit plans and most other tax-exempt organizations, including IRAs and other retirement plans, are subject to federal income tax on unrelated business taxable income. Virtually all of our income will be unrelated business taxable income and will be taxable to a tax-exempt unitholder.

Non-U.S. Unitholders are taxed by the United States on income effectively connected with a U.S. trade or business ("effectively connected income") and on certain types of U.S.-source non-effectively connected income (such as dividends), unless exempted or further limited by an income tax treaty. Each Non-U.S. Unitholder will be considered to be engaged in business in the United States because of its ownership of our units. Furthermore, it is probable that Non-U.S. Unitholders will be deemed to conduct such activities through a permanent establishment in the United States within the meaning of any applicable tax treaty. Consequently, each Non-U.S. Unitholder will be required to file federal tax returns to report its share of our income, gain, loss or deduction and pay federal income tax on its share of our net income or gain. Moreover, under rules applicable to publicly traded partnerships, distributions to Non-U.S. Unitholders are subject to withholding at the highest applicable effective tax rate. Each Non-U.S. Unitholder must obtain a taxpayer identification number from the IRS and submit that number to our transfer agent on a Form W-8BEN or W-8BEN-E (or other applicable or successor form) in order to obtain credit for these withholding taxes.

In addition, if a Non-U.S. Unitholder is classified as a non-U.S. corporation, it will be treated as engaged in a United States trade or business and may be subject to the U.S. branch profits tax at a rate of 30%, in addition to regular federal income tax, on its share of our income and gain as adjusted for changes in the foreign corporation's "U.S. net equity" to the extent reflected in the corporation's earnings and profits. That tax may be reduced or eliminated by an income tax treaty between the United States and the country in which the foreign corporate unitholder is a "qualified resident." In addition, this type of unitholder is subject to special information reporting requirements under Section 6038C of the Code.

A Non-U.S. Unitholder who sells or otherwise disposes of a unit will be subject to federal income tax on gain realized from the sale or disposition of that unit to the extent the gain is effectively connected with a U.S. trade or business of the Non-U.S. Unitholder. Under a ruling published by the IRS interpreting the scope of "effectively connected income," gain realized by a Non-U.S. Unitholder from the sale of its interest in a partnership that is engaged in a trade or business in the United States will be considered to be "effectively connected" with a U.S. trade or business. Although one court that recently reviewed the IRS position rejected it as unpersuasive, part or all of a Non-U.S. Unitholder's gain from the sale or other disposition of units may be treated as effectively connected with a unitholder's indirect U.S. trade or business constituted by its investment in us.

Moreover, under the Foreign Investment in Real Property Tax Act, as long as our partnership units continue to be regularly traded on an established securities market, a Non-U.S. Unitholder generally will only be subject to federal income tax upon the sale or disposition of a unit if at any time during the shorter of the five-year period ending on the date of the disposition or the Non-U.S. Unitholder's holding period for the unit (i) such Non-U.S. Unitholder owned (directly or indirectly constructively applying certain attribution rules) more than 5% of our units and (ii) 50% or more of the fair market

value of our real property interests and other assets used or held for use in a trade or business consisted of U.S. real property interests (which include U.S. real estate, including land, improvements, and associated personal property, and interests in certain entities holding U.S. real estate). If our units were not considered to be regularly traded on an established securities market, such Non-U.S. Unitholder (regardless of the percentage of units owned) would be subject to U.S. federal income tax on a taxable disposition of our units, and a 15% withholding tax would apply to the gross proceeds from such disposition (as described in the preceding paragraph). More than 50% of our assets may consist of U.S. real property interests. Therefore, each Non-U.S. Unitholder may be subject to federal income tax on gain from the sale or disposition of its units.

We intend to furnish to each unitholder, within 90 days after the close of each taxable year, specific tax information, including a Schedule K-1, which describes its share of our income, gain, loss and deduction for our preceding taxable year. In preparing this information, which will not be reviewed by counsel, we will take various accounting and reporting positions, some of which have been mentioned earlier, to determine each unitholder's share of income, gain, loss and deduction. We cannot assure our unitholders that those positions will yield a result that conforms to all of the requirements of the Code, Treasury Regulations or administrative interpretations of the IRS.

The IRS may audit our federal income tax information returns. Neither we nor Vinson & Elkins L.L.P. can assure prospective unitholders that the IRS will not successfully challenge the positions we adopt, and such a challenge could adversely affect the value of the units. Adjustments resulting from an IRS audit may require each unitholder to adjust a prior year's tax liability and may result in an audit of the unitholder's own return. Any audit of a unitholder's return could result in adjustments unrelated to our returns.

Publicly traded partnerships are treated as entities separate from its owners for purposes of federal income tax audits, judicial review of administrative adjustments by the IRS and tax settlement proceedings. The tax treatment of partnership items of income, gain, loss and deduction are determined in a partnership proceeding rather than in separate proceedings of the partners. The Code requires that one partner be designated as the "Tax Matters Partner" for these purposes, and our partnership agreement designates our general partner.

The Tax Matters Partner can extend the statute of limitations for assessment of tax deficiencies against unitholders for items in our returns. The Tax Matters Partner may bind a unitholder with less than a 1% profits interest in us to a settlement with the IRS unless that unitholder elects, by filing a statement with the IRS, not to give that authority to the Tax Matters Partner. The Tax Matters Partner may seek judicial review, by which all the unitholders are bound, of a final partnership administrative adjustment and, if the Tax Matters Partner fails to seek judicial review, judicial review may be sought by any unitholder having at least a 1% interest in profits or by any group of unitholders having in the aggregate at least a 5% interest in profits. However, only one action for judicial review may go forward, and each unitholder with an interest in the outcome may participate in that action.

A unitholder must file a statement with the IRS identifying the treatment of any item on its federal income tax return that is not consistent with the treatment of the item on our return. Intentional or negligent disregard of this consistency requirement may subject a unitholder to substantial penalties.

Pursuant to the Bipartisan Budget Act of 2015 (the "Bipartisan Budget Act"), for taxable years beginning after December 31, 2017, if the IRS makes audit adjustments to our income tax returns, it may assess and collect any taxes (including any applicable penalties and interest) resulting from such

audit adjustment directly from us, unless we elect to have our general partner and unitholders take any audit adjustment into account in accordance with their interests in us during the taxable year under audit. Similarly, for such taxable years, if the IRS makes audit adjustments to income tax returns filed by an entity in which we are a member or partner, it may assess and collect any taxes (including penalties and interest) resulting from such audit adjustment directly from such entity. Generally, we expect to elect to have our general partner and unitholders take any such audit adjustment into account in accordance with their interests in us during the taxable year under audit, but there can be no assurance that such election will be effective in all circumstances. With respect to audit adjustments as to an entity in which we are a member or partner, the Joint Committee of Taxation has stated that we would not be able to have our general partner and our unitholders take such audit adjustment into account. If we are unable to have our general partner and our unitholders take such audit adjustment into account in accordance with their interests in us during the taxable year under audit, our then current unitholders may bear some or all of the tax liability resulting from such audit adjustment, even if such unitholders did not own our units during the taxable year under audit. If, as a result of any such audit adjustment, we are required to make payments of taxes, penalties, and interest, our cash available for distribution to our unitholders might be substantially reduced. These rules are not applicable for taxable years beginning on or prior to December 31, 2017. Congress has proposed changes to the Bipartisan Budget Act, and we anticipate that amendments may be made. Accordingly, the manner in which these rules may apply to us in the future is uncertain.

Additionally, pursuant to the Bipartisan Budget Act, the Code will no longer require that we designate a Tax Matters Partner. Instead, for taxable years beginning after December 31, 2017, we will be required to designate a partner, or other person, with a substantial presence in the United States as the partnership representative ("Partnership Representative"). The Partnership Representative will have the sole authority to act on our behalf for purposes of, among other things, federal income tax audits and judicial review of administrative adjustments by the IRS. If we do not make such a designation, the IRS can select any person as the Partnership Representative. We currently anticipate that we will designate our general partner as the Partnership Representative. Further, any actions taken by us or by the Partnership Representative on our behalf with respect to, among other things, federal income tax audits and judicial review of administrative adjustments by the IRS, will be binding on us and all of the unitholders.

Withholding taxes may apply to certain types of payments made to "foreign financial institutions" (as defined in the Code) and certain other non-U.S. entities. Specifically, a 30% withholding tax may be imposed on interest, dividends and other fixed or determinable annual or periodical gains, profits and income from sources within the United States ("FDAP Income"), or gross proceeds from the sale or other disposition of any property of a type which can produce interest or dividends from sources within the United States ("Gross Proceeds") paid to a foreign financial institution or to a "non-financial foreign entity" (as defined in the Code), unless (i) the foreign financial institution undertakes certain diligence and reporting, (ii) the non-financial foreign entity either certifies it does not have any substantial U.S. owners or furnishes identifying information regarding each substantial U.S. owner or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. If the payee is a foreign financial institution and is subject to the diligence and reporting requirements in clause (i) above, it must enter into an agreement with the U.S. Department of the Treasury requiring, among other things, that it undertake to identify accounts held by certain U.S. persons or U.S.-owned foreign entities, annually report certain information about such accounts, and withhold 30% on payments to noncompliant foreign financial institutions and certain other account holders. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing these requirements may be subject to different rules.

These rules generally apply to payments of FDAP Income currently and generally will apply to payments of relevant Gross Proceeds made on or after January 1, 2019. Thus, to the extent we have FDAP Income or we have Gross Proceeds on or after January 1, 2019 that are not treated as effectively connected with a U.S. trade or business (please read "—Tax-Exempt Organizations and Other Investors"), a unitholder who is foreign financial institution or certain other non-U.S. entity, or a person that hold its units through such foreign entities, may be subject to withholding on distributions they receive from us, or its distributive share of our income, pursuant to the rules described above.

Each prospective unitholder should consult its own tax advisors regarding the potential application of these withholding provisions to its investment in our units.

Persons who hold an interest in us as a nominee for another person are required to furnish to us:

Each broker and financial institution is required to furnish additional information, including whether such broker or financial institution is a U.S. person and specific information on units such broker or financial institution acquires, holds or transfers for its own account. A penalty of $260 per failure, up to a maximum of $3,218,500 per calendar year, is imposed by the Code for failure to report that information to us. The nominee is required to supply the beneficial owner of the units with the information furnished to us.

Certain penalties may be imposed as a result of an underpayment of tax that is attributable to one or more specified causes, including negligence or disregard of rules or regulations, substantial understatements of income tax and substantial valuation misstatements. No penalty will be imposed, however, for any portion of an underpayment if it is shown that there was a reasonable cause for the underpayment of that portion and that the taxpayer acted in good faith regarding the underpayment of that portion. We do not anticipate that any accuracy-related penalties will be assessed against us.

In addition to federal income taxes, unitholders may be subject to other taxes, including state and local income taxes, unincorporated business taxes, and estate, inheritance or intangibles taxes that may be imposed by the various jurisdictions in which we conduct business or own property now or in the future or in which the unitholder is a resident. We conduct business or own property in many states in the United States. Some of these states may impose an income tax on individuals, corporations and

other entities. As we make acquisitions or expand our business, we may own property or conduct business in additional states that impose a personal income tax. Although an analysis of those various taxes is not presented here, each prospective unitholder should consider its potential impact on its investment in us.

A unitholder may be required to file income tax returns and pay income taxes in some or all of the jurisdictions in which we do business or own property, though such unitholder may not be required to file a return and pay taxes in certain jurisdictions because its income from such jurisdictions falls below the jurisdiction's filing and payment requirement. Further, a unitholder may be subject to penalties for a failure to comply with any filing or payment requirement applicable to such unitholder. Some of the jurisdictions may require us, or we may elect, to withhold a percentage of income from amounts to be distributed to a unitholder who is not a resident of the jurisdiction. Withholding, the amount of which may be greater or less than a particular unitholder's income tax liability to the jurisdiction, generally does not relieve a nonresident unitholder from the obligation to file an income tax return.

It is the responsibility of each unitholder to investigate the legal and tax consequences, under the laws of pertinent jurisdictions, of its investment in us. We strongly recommend that each prospective unitholder consult, and depend upon, its own tax counsel or other advisor with regard to those matters. Further, it is the responsibility of each unitholder to file all state, local and non-U.S., as well as federal tax returns that may be required of it. Vinson & Elkins L.L.P. has not rendered an opinion on the state, local, alternative minimum tax or non-U.S. tax consequences of an investment in us.

This prospectus covers the offering for resale from time to time, in one or more offerings, of up to 69,696,542 common units issuable upon conversion of 69,696,542 Series A preferred units by the selling unitholders. Such common units will be issued to each selling unitholder upon such holder's exercise of its right to convert (the "Conversion Right") its Series A preferred units on a one-for-one basis, subject to customary anti-dilution adjustments, at any time after January 28, 2018 (or prior to a liquidation), in whole or in part, subject to certain limitations. The Series A preferred units were acquired by the selling unitholders on January 28, 2016 through a private placement of 61,030,127 Series A preferred units and through subsequent quarterly distributions of additional Series A preferred units thereafter by us in lieu of cash.

Any issuance of the common units to the selling unitholders in connection with exercise of the Conversion Right will be, and each issuance of the Series A preferred units was, exempt from the registration requirements of the Securities Act of 1933, as amended (the "Securities Act"). We are registering the offering by the selling unitholders of the common units described below pursuant to the provisions of the Registration Rights Agreement dated January 28, 2016 between us and the purchasers named on Schedule A thereto.

The following table sets forth information relating to the selling unitholders as of November 28, 2017 based on information supplied to us by the selling unitholders on or prior to that date. We have not sought to verify such information. Information concerning the selling unitholders may change over time and selling unitholders may be added; if necessary, we will supplement this prospectus accordingly. Except as set forth below, none of the selling unitholders is a broker-dealer registered under Section 15 of the Exchange Act or an affiliate of a broker-dealer registered under Section 15 of the Exchange Act. The selling unitholders may hold or acquire at any time common units in addition to those offered by this prospectus and may have acquired additional common units since the date on which the information reflected herein was provided to us. In addition, the selling unitholders may have sold, transferred or otherwise disposed of some or all of their common units since the date on which the information reflected herein was provided to us and may in the future sell, transfer or otherwise dispose of some or all of their common units in private placement transactions exempt from or not subject to the registration requirements of the Securities Act.

The beneficial ownership information presented below assumes that all 69,696,542 Series A preferred units have been exchanged pursuant to the Conversion Right on a one-for-one basis into common units and such common units are held by the selling unitholders.

Selling Unitholders

EMG Fund IV PAA Holdings, LLC(1)	19,976,725		2.5	%	19,976,725		—	—
EnCap Energy Capital Fund X, L.P.(2)	12,429,961		1.6	%	12,429,961		—	—
EnCap Flatrock Midstream Fund III, L.P.(2)	12,429,961		1.6	%	12,429,961		—	—
FR KA Plains Holdings, LLC	12,429,961		1.6	%	12,429,961		—	—
Stonepeak PAA Holdings LLC	6,214,979		*		6,214,979		—	—
Kaiser Foundation Hospitals	4,439,269		*		4,439,269		—	—
Kayne Anderson MLP Fund, L.P.(3)	1,398,787	(4)	*		554,905	(4)	843,882	*
Massachusetts Mutual Life Insurance Company	1,119,211	(5)	*		443,923	(5)	675,288	*
Kayne Anderson Midstream Institutional Fund, L.P.(3)	443,923		*		443,923		—	—
Kanti (QP), L.P.(3)	356,773	(6)	*		195,323	(6)	161,450	*
Kayne Select Midstream Recovery Fund, L.P.(3)	110,978		*		110,978		—	—
Kayne Anderson Non-Traditional Investments, L.P.(3)	76,421	(7)	*		26,634	(7)	49,787	*

*: Less than one percent.
(1): John T. Raymond is the Chief Executive Officer of the selling unitholder. Mr. Raymond also serves on the board of directors of PAGP GP as the designee of an affiliate of the selling unitholder.
(2): Gary Petersen serves on the board of managers of the controlling entity of the selling unitholder. Mr. Petersen also serves on the board of directors of PAGP GP.
(3): Representatives of the selling unitholder have advised us that the selling unitholder is an affiliate of a U.S. registered broker-dealer; however, the selling unitholder acquired the common units in the ordinary course of business and, at the time of acquisition, had no agreements or understandings, directly or indirectly, with any party to distribute the common units held by the selling unitholder. Kayne Anderson Capital Advisors, L.P. ("KACALP") serves as the investment manager of the selling unitholder. Robert Sinnott is the co-chair of KACALP. In addition, Mr. Sinnott serves on the board of directors of PAGP GP as the designee of an affiliate of the selling unitholder.
(4): The selling unitholder will receive 554,905 common units upon exercise of the Conversion Right; 843,882 common units were previously owned.
(5): The selling unitholder will receive 443,923 common units upon exercise of the Conversion Right; 675,288 common units were previously owned.
(6): The selling unitholder will receive 195,323 common units upon exercise of the Conversion Right; 161,450 common units were previously owned.
(7): The selling unitholder will receive 26,634 common units upon exercise of the Conversion Right; 49,787 common units were previously owned.

In the event a prospectus supplement is used to reflect the sale of common units hereunder, it will set forth, with respect to the selling unitholders:

All expenses incurred with the registration of the common units owned by the selling unitholders will be borne by us.

We are registering the common units offered by this prospectus on behalf of the selling unitholders. As used in this prospectus, "selling unitholders" includes partners, pledgees, donees (including charitable organizations), transferees or other successors-in-interest selling common units received from any selling unitholder identified in this prospectus after the date of this prospectus.

Subject to certain restrictions on transfer that may be applicable to the selling unitholders, the selling unitholders intend to offer and sell the common units offered by this prospectus by one or more of, or a combination of, the following methods:

The offering price per common unit will be determined from time to time by the selling unitholders in connection with, and at the time of, the sale by such selling unitholders. The selling unitholders may price the common units at:

In addition, the selling unitholders may from time to time sell common units in compliance with Rule 144 under the Securities Act, if available, or pursuant to other available exemptions from the registration requirements under the Securities Act, rather than pursuant to this prospectus. The selling unitholders may be required by the securities laws of certain states to offer and sell the common units only through registered or licensed brokers or dealers.

The selling unitholders may act independently of us in making decisions with respect to the timing, manner and size of each of their sales.

The selling unitholders may authorize underwriters acting as their agent to offer and sell common units upon the terms and conditions as are set forth in an applicable prospectus supplement. In connection with the sale of these common units, underwriters may be deemed to have received compensation from the selling unitholders in the form of underwriting discounts or commissions and may also receive commissions from purchasers of common units for whom they may act as agent or to whom they sell as principals, or both. Underwriters may sell common units to or through dealers. Dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agent or to whom they sell as principals, or both. A member firm of the NYSE may be engaged to act as the agent of the selling unitholders in the sale of common units.

As of the date of this prospectus, the selling unitholders have not engaged any underwriter, broker, dealer or agent in connection with the offer and sale of common units pursuant to this prospectus by the selling unitholders. To the extent required, the names of the specific managing underwriter or underwriters, if any, as well as other important information, will be set forth in an applicable prospectus supplement. In that event, any underwriting compensation paid by the selling unitholders to underwriters or agents in connection with the offering of these common units, and any discounts, concessions or commissions allowed by underwriters to participating dealers, will be set forth in the applicable prospectus supplement.

Broker-dealers may also receive compensation in the form of underwriting discounts or commissions and may receive commissions from purchasers of the common units for whom they may act as agents. If any broker-dealer purchases the common units as principal, it may effect resales of the common units from time to time to or through other broker-dealers, and other broker-dealers may receive compensation in the form of concessions or commissions from the purchasers of common units for whom they may act as agents.

We will pay the costs and expenses related to the registration and offering of the common units offered hereby. We will not pay any underwriting fees, discounts and selling commissions (and similar fees or arrangements associated therewith) allocable to each selling unitholder's sale of its common units; these expenses will be paid by the selling unitholders.

We have agreed to indemnify the selling unitholders against certain liabilities to which they may become subject in connection with the sale of the common units owned by the selling unitholders and registered under this prospectus, including liabilities arising under the Securities Act. We may indemnify underwriters, brokers, dealers and agents against specific liabilities to which they may become subject in connection with the sale of the common units owned by the selling unitholders and registered under this prospectus, including liabilities under the Securities Act.

Any underwriters, brokers, dealers and agents who participate in any sale of the common units may also engage in transactions with, or perform services for, us or our affiliates in the ordinary course of their businesses.

Because FINRA views our common units as interests in a direct participation program, any offering of common units under the registration statement of which this prospectus forms a part will be made in compliance with Rule 2310 of the FINRA Rules.

In connection with offerings under this shelf registration statement and in compliance with applicable law, underwriters, brokers or dealers may engage in transactions which stabilize or maintain the market price of the common units at levels above those that might otherwise prevail in the open market. Specifically, underwriters, brokers or dealers may overallot in connection with offerings, creating a short position in the common units for their own accounts. For the purpose of covering a syndicate short position or stabilizing the price of the common units, the underwriters, brokers or dealers may place bids for the common units or effect purchases of the common units in the open market. Finally, the underwriters may impose a penalty whereby selling concessions allowed to syndicate members or other brokers or dealers for distribution of the common units in offerings may be reclaimed by the syndicate if the syndicate repurchases the previously distributed common units in transactions to cover short positions, in stabilization transactions or otherwise. These activities may stabilize, maintain or otherwise affect the market price of the common units, which may be higher than the price that might otherwise prevail in the open market, and, if commenced, may be discontinued at any time.

To the extent required, this prospectus may be amended or supplemented from time to time to describe a specific plan of distribution. The place and time of delivery for the common units in respect of which this prospectus is delivered will be set forth in the accompanying prospectus supplement.

The validity of the common units will be passed upon for us by Vinson & Elkins L.L.P., Houston, Texas. If certain legal matters in connection with an offering of the common units made by this prospectus and a related prospectus supplement are passed on by counsel for the underwriters of such offering, that counsel will be named in the applicable prospectus supplement related to that offering.

The financial statements and management's assessment of the effectiveness of internal control over financial reporting (which is included in Management's Report on Internal Control over Financial Reporting) incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2016 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

Set forth below are the expenses (other than underwriting discounts and commissions) expected to be incurred in connection with the issuance and distribution of the securities registered hereby. With the exception of the SEC registration fee, the amounts set forth below are estimates.


SEC registration fee	$	161,830
Legal fees and expenses		100,000
Accounting fees and expenses		10,000
Printing expenses		20,000

Total	$	291,830

Section 17-108 of the Delaware Revised Uniform Limited Partnership Act empowers a Delaware limited partnership to indemnify and hold harmless any partner or other person from and against all claims and demands whatsoever. The partnership agreement of Plains All American Pipeline, L.P. provides that Plains All American Pipeline, L.P. will indemnify the general partner, any departing partner, any person who is or was an affiliate of the general partner or any departing partner, and any person who is or was a member, partner, officer, director, employee, agent or trustee of the general partner or any departing partner or any affiliate of the general partner or any departing partner, or any person who is or was serving at the request of the general partner or any departing partner or any affiliate of the general partner or any departing partner as an officer, director, employee, member, partner, agent, fiduciary or trustee of another person (each, an "Indemnitee"), to the fullest extent permitted by law, from and against any and all losses, claims, damages, liabilities (joint or several), expenses (including, without limitation, legal fees and expenses), judgments, fines, penalties, interest, settlements and other amounts arising from any and all claims, demands, actions, suits or proceedings, whether civil, criminal, administrative or investigative, in which any Indemnitee may be involved, or is threatened to be involved, as a party or otherwise, by reason of its status as any of the foregoing; provided that in each case the Indemnitee acted in good faith and in a manner that such Indemnitee reasonably believed to be in or not opposed to the best interests of Plains All American Pipeline, L.P. and, with respect to any criminal proceeding, had no reasonable cause to believe his, her or its conduct was unlawful. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to any Indemnitee pursuant to the foregoing provisions, the registrant has been informed that in the opinion of the SEC such indemnification is against public policy as expressed in the Act and is therefore unenforceable.

Any indemnification under these provisions will be only out of the assets of Plains All American Pipeline, L.P., and the general partner shall not be personally liable for, or have any obligation to contribute or loan funds or assets to Plains All American Pipeline, L.P. to enable it to effectuate such indemnification. Plains All American Pipeline, L.P. is authorized to purchase (or to reimburse PAA GP Holdings LLC or its affiliates for the cost of) insurance against liabilities asserted against and expenses incurred by such persons in connection with Plains All American Pipeline, L.P.'s activities, regardless of whether Plains All American Pipeline, L.P. would have the power to indemnify such person against such liabilities under the provisions described above.

Section 18-108 of the Delaware Limited Liability Company Act provides that, subject to such standards and restrictions, if any, as are set forth in its limited liability company agreement, a Delaware limited liability company may, and has the power to, indemnify and hold harmless any member or

manager or other person from and against any and all claims and demands whatsoever. The limited liability company agreement of PAA GP Holdings LLC provides for the indemnification of (a) any of its original members ("Existing Owner") or any owner of a direct or indirect 10% ownership interest in Plains AAP, L.P.'s Class A units ("Qualifying Interest Holder"), (b) any Person who is or was an affiliate of PAA GP Holdings LLC, any Existing Owner or any Qualifying Interest Holder, (c) any person who is or was a managing member, manager, general partner, shareholder, director, officer, fiduciary, agent or trustee of PAA GP Holdings LLC, any Existing Owner or any Qualifying Interest Holder or any affiliate thereof, (d) any Person who is or was serving at the request of PAA GP Holdings LLC, any Existing Owner or any Qualifying Interest Holder or any affiliate of thereof as a member, manager, partner, director, officer, fiduciary, agent or trustee of another person in furtherance of the business or affairs of PAA GP Holdings LLC or its subsidiaries (provided, that a person shall not be indemnified by reason of providing, on a fee-for-services basis, trustee, fiduciary or custodial services), and (e) any person the board of directors of PAA GP Holdings LLC designates an indemnitee (collectively, the "Indemnitees"), from and against any and all losses, claims, demands, costs, damages, liabilities, expenses of any nature (including reasonable attorneys' fees and disbursements), judgments, fines, settlements and other amounts arising from any and all claims, demands, actions, suits or proceedings, civil, criminal, administrative or investigative, in which such person may be involved, or threatened to be involved, as a party or otherwise, by reason of his, her or its status as an Indemnitee, regardless of whether an Indemnitee continues to be an Indemnitee at the time any such liability or expense is paid or incurred, if such Indemnitee acted in good faith and in a manner he, she or it reasonably believed to be in, or not opposed to, the interests of PAA GP Holdings LLC and with respect to any criminal proceeding, had no reason to believe his, her or its conduct was unlawful. Expenses incurred by an Indemnitee in defending any such claim, demand, action, suit or proceeding will, from time to time, be advanced by PAA GP Holdings LLC prior to the final disposition of such claim, demand, action, suit or proceeding upon receipt by PAA GP Holdings LLC of an undertaking by or on behalf of the Indemnitee to repay such amounts if it is ultimately determined that the Indemnitee is not entitled to be indemnified. PAA GP Holdings LLC is authorized to purchase and maintain insurance, on behalf of the members of its Board of Directors, its officers and such other persons as the Board of Directors may determine, against any liability that may be asserted against or expense that may be incurred by such person in connection with the activities of PAA GP Holdings LLC.

The underwriting agreements that we may enter into with respect to the offer and sale of securities covered by this registration statement will contain certain provisions for the indemnification of directors and officers and the underwriters or sales agent, as applicable, against civil liabilities under the Securities Act.

B. The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of Plains All American Pipeline, L.P.'s annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in this registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of the securities at that time shall be deemed to be the initial bona fide offering thereof.

C. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers, and controlling persons of the registrant pursuant to the provisions described in Item 15 above, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer, or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by a director, officer, or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of the issue.

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Houston, State of Texas on November 30, 2017.



PLAINS ALL AMERICAN PIPELINE, L.P.
By:	PAA GP LLC, its general partner
By:	Plains AAP, L.P., its sole member
By:	Plains All American GP LLC, its general partner
By:	Plains GP Holdings, L.P., its sole member
By:	PAA GP Holdings LLC, its general partner
By:	/s/ GREG L. ARMSTRONG
	Name:	Greg L. Armstrong
	Title:	Chairman of the Board and Chief Executive Officer

All those persons whose signatures appear below do hereby constitute and appoint Al Swanson and Richard McGee, and each of them, our true and lawful attorney-in-fact and agent, to do any and all acts and things in our names and on our behalf in our capacities as directors and officers and to execute any and all instruments for us and in our name in the capacities indicated below, which said attorney and agent may deem necessary or advisable to enable said registrant to comply with the Securities Act of 1933, as amended, and any rules, regulations and requirements of the Securities and Exchange Commission, in connection with the registration statements, or any registration statement for this offering that is to be effective upon filing pursuant to Rule 462 under the Securities Act of 1933, as amended, including specifically, but without limitation, power and authority to sign for us or any of us in our names in the capacities indicated below, any and all amendments (including post-effective amendments) hereof; and we do hereby ratify and confirm all that said attorneys and agents shall do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated below.

PAA GP HOLDINGS LLC, for itself as the general partner of PLAINS GP HOLDINGS, L.P., which is the sole member of PLAINS ALL AMERICAN GP LLC, which is the general partner of PLAINS AAP, L.P., which is the sole member of PAA GP LLC, which is the general partner of PLAINS ALL AMERICAN PIPELINE, L.P.


/s/ HARRY N. PEFANIS Harry N. Pefanis	President, Chief Operating Officer and Director	November 30, 2017
/s/ WILLIE C. CHIANG Willie C. Chiang	Executive Vice President, Chief Operating Officer (U.S.) and Director	November 30, 2017
/s/ AL SWANSON Al Swanson	Executive Vice President and Chief Financial Officer (Principal Financial Officer)	November 30, 2017
/s/ CHRIS HERBOLD Chris Herbold	Vice President—Accounting and Chief Accounting Officer (Principal Accounting Officer)	November 30, 2017
/s/ OSCAR K. BROWN Oscar K. Brown	Director	November 30, 2017
/s/ VICTOR BURK Victor Burk	Director	November 30, 2017
/s/ EVERARDO GOYANES Everardo Goyanes	Director	November 30, 2017
Gary R. Petersen	Director	November 30, 2017
/s/ JOHN T. RAYMOND John T. Raymond	Director	November 30, 2017
/s/ BOBBY S. SHACKOULS Bobby S. Shackouls	Director	November 30, 2017
/s/ ROBERT V. SINNOTT Robert V. Sinnott	Director	November 30, 2017
/s/ J. TAFT SYMONDS J. Taft Symonds	Director	November 30, 2017
/s/ CHRISTOPHER M. TEMPLE Christopher M. Temple	Director	November 30, 2017


Large accelerated filer ý		Accelerated filer o		Non-accelerated filer o (Do not check if a smaller reporting company)		Smaller reporting company o Emerging growth company o


1.1	+	—	Form of Underwriting Agreement
4.1		—	Registration Rights Agreement, dated as of January 28, 2016, by and among Plains All American Pipeline, L.P. and the other parties signatory thereto (incorporated by reference to Exhibit 4.1 to our Current Report on Form 8-K filed on February 2, 2016).
5.1*		—	Opinion of Vinson & Elkins L.L.P. as to the legality of the securities being registered
8.1*		—	Opinion of Vinson & Elkins L.L.P. relating to tax matters
23.1*		—	Consent of PricewaterhouseCoopers LLP
23.2*		—	Consent of Vinson & Elkins L.L.P. (contained in Exhibits 5.1 and 8.1)
24.1*		—	Powers of Attorney (included on the signature page)


Delaware (State or Other Jurisdiction of Incorporation or Organization)		76-0582150 (I.R.S. Employer Identification No.)


About This Prospectus			2
Where You Can Find More Information			3
Forward-Looking Statements			4
About Plains All American Pipeline, L.P.			6
Risk Factors			8
Use of Proceeds			9
Description of Our Common Units			10
Material U.S. Federal Income Tax Consequences			11
Selling Unitholders			27
Plan of Distribution			30
Legal Matters			32
Experts			32


/s/ GREG L. ARMSTRONG Greg L. Armstrong		Chairman of the Board and Chief Executive Officer (Principal Executive Officer)		November 30, 2017