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UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

S QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2013

or

£ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                    to                   

Commission File Number:  001-35358

TC PipeLines, LP

(Exact name of registrant as specified in its charter)

877-290-2772

(Registrant’s telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Yes x                                   No ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).

Yes x                                   No ¨

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

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Yes ¨                                     No x

As of July 29, 2013, there were 62,327,766 of the registrant’s common units outstanding.

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TC PIPELINES, LP

All amounts are stated in United States dollars unless otherwise indicated.

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DEFINITIONS

The abbreviations, acronyms, and industry terminology used in this quarterly report are defined as follows:

Unless the context clearly indicates otherwise, TC PipeLines, LP, its subsidiaries and equity investees are collectively referred to in this quarterly report as “we,” “us,” “our” and “the Partnership.” We use “our pipeline systems” and “our pipelines” when referring to the Partnership’s ownership interests in Great Lakes, Northern Border, GTN, Bison , North Baja and Tuscarora.

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PART I

FORWARD-LOOKING STATEMENTS AND CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

This report includes certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements are identified by words and phrases such as: “anticipate,” “estimate,” “expect,” “project,” “intend,” “plan,” “believe,” “forecast,” “should,” “predict,” “could,” “will,” “may,” and other terms and expressions of similar meaning. The absence of these words, however, does not mean that the statements are not forward-looking. These statements are based on management’s beliefs and assumptions and on currently available information and include, but are not limited to, statements regarding anticipated financial performance, future capital expenditures, liquidity, market or competitive conditions, regulations, organic or strategic growth opportunities, contract renewals and ability to market open capacity, business prospects, outcome of regulatory proceedings and cash distributions to unitholders.

Forward-looking statements involve risks and uncertainties that may cause actual results to differ materially from the results predicted. Factors that could cause actual results to differ materially from those contemplated in forward-looking statements include, but are not limited to:

·                  the ability to grow distributions through accretive expansions or acquisitions;

·                  the ability of our pipeline systems to sell available capacity on favorable terms and renew expiring contracts which are affected by, among other factors:

o                 demand for natural gas;

o                 changes in relative cost structures and production levels of natural gas producing basins;

o                 natural gas prices and regional differences;

o                 weather conditions;

o                 availability and location of natural gas supplies in Canada and the U.S.;

o                 competition from other pipeline systems;

o                 natural gas storage levels;

o                 the level of production of natural gas liquids and the subsequent impact on relative competitiveness of natural gas producing basins; and

o                 rates and terms of service;

·                  increases in operational or compliance costs resulting from changes in laws and governmental regulations affecting our pipeline systems, particularly regulations issued by the Federal Energy Regulatory Commission (FERC), the U.S. Environmental Protection Agency (EPA), U.S. Department of Transportation (DOT) and U.S. DOT Pipeline and Hazardous Materials Safety Administration (PHMSA);

·                  the outcome and frequency of rate proceedings on our pipeline systems;

·                  our ability to identify and complete expansion projects and other accretive growth opportunities;

·                  the performance by the shippers of their contractual obligations on our pipeline systems;

·                  changes in the taxation of master limited partnership investments by states or the federal government such as the elimination of pass-through taxation or tax deferred distributions;

·                  potential conflicts of interest between TC PipeLines GP, Inc., our general partner (General Partner), its affiliates and us;

·                  the ability to maintain secure operation of our information technology;

·                  the impact of any impairment charges;

·                  operating hazards, casualty losses and other matters beyond our control;

·                  the level of our indebtedness, including the indebtedness of our pipeline systems, and the availability of capital; and

·                  unfavorable economic conditions and the impact on capital markets.

These and other risks are described in greater detail in Part II, Item 1A. “Risk Factors” in this Form 10-Q and in our Form 10-K for the year ended December 31, 2012. All forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by these factors. All forward-looking statements are made only as of the date made and except as required by applicable law, we undertake no obligation to update any forward-looking statements to reflect new information, subsequent events or other changes.

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PART I – FINANCIAL INFORMATION

Item 1.                                 Financial Statements

TC PIPELINES, LP

CONSOLIDATED STATEMENT OF INCOME

TC PIPELINES, LP

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME

The accompanying notes are an integral part of these consolidated financial statements.

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TC PIPELINES, LP

CONSOLIDATED BALANCE SHEET

Subsequent events (Note 13)

The accompanying notes are an integral part of these consolidated financial statements.

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TC PIPELINES, LP

CONSOLIDATED STATEMENT OF CASH FLOWS

The accompanying notes are an integral part of these consolidated financial statements.

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TC PIPELINES, LP

CONSOLIDATED STATEMENT OF CHANGES IN PARTNERS’ EQUITY

The accompanying notes are an integral part of these consolidated financial statements.

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TC PIPELINES, LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

NOTE 1                         ORGANIZATION

TC PipeLines, LP and its subsidiaries are collectively referred to herein as the Partnership. The Partnership was formed by TransCanada PipeLines Limited, a wholly-owned subsidiary of TransCanada Corporation (TransCanada Corporation together with its subsidiaries collectively referred to herein as TransCanada), to acquire, own and participate in the management of energy infrastructure assets in North America.

NOTE 2                         SIGNIFICANT ACCOUNTING POLICIES

The accompanying financial statements and related notes have been prepared in accordance with United States generally accepted accounting principles (GAAP) and amounts are stated in U.S. dollars. The results of operations for the three and six months ended June 30, 2013 and 2012 are not necessarily indicative of the results that may be expected for a full fiscal year. The accompanying financial statements should be read in conjunction with the financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2012. That report contains a more comprehensive summary of the Partnership’s major accounting policies. In the opinion of management, the accompanying financial statements contain all of the appropriate adjustments, all of which are normally recurring adjustments unless otherwise noted, considered necessary to present fairly the financial position of the Partnership, the results of operation and cash flows for the respective periods. Our significant accounting policies are consistent with those disclosed in Note 2 of the financial statements in our Annual Report on Form 10-K for the year ended December 31, 2012. Certain items from that Note are repeated or updated below as necessary to assist in understanding the accompanying financial statements.

(a) Basis of Presentation

The Partnership uses the equity method of accounting for its investments in Great Lakes, Northern Border, GTN and Bison, over which it is able to exercise significant influence. The Partnership consolidates its investments in North Baja and Tuscarora.

(b) Use of Estimates

The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Although management believes these estimates are reasonable, actual results could differ from these estimates.

NOTE 3                         ACCOUNTING PRONOUNCEMENTS

Future Accounting Changes

Obligations Resulting from Joint and Several Liability Arrangements

In February 2013, the Financial Accounting Standards Board (FASB) issued guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. Examples of obligations within the scope of this Accounting Standards Update (ASU) include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. This ASU is effective retrospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The Partnership is currently evaluating the impact of the adoption of this ASU on its consolidated financial statements, but does not expect it to have a material impact.

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NOTE 4                         INVESTMENTS IN UNCONSOLIDATED AFFILIATES

Great Lakes, Northern Border, GTN and Bison are regulated by FERC and are operated by TransCanada. The Partnership uses the equity method of accounting for its interests in its equity investees.

(a)           Equity earnings from Northern Border is net of the 12-year amortization of a $10 million transaction fee paid to the operator of Northern Border at the time of the Partnership’s additional 20 percent interest acquisition in April 2006.

Great Lakes

The Partnership made an equity contribution to Great Lakes of $4 million in the first quarter of 2013. This amount represents the Partnership’s 46.45 percent share of a $9 million cash call from Great Lakes to make a scheduled debt repayment.

The Partnership recorded no undistributed earnings from Great Lakes for the six months ended June 30, 2013 and 2012.

The summarized financial information for Great Lakes is as follows:

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Northern Border

In January 2013, FERC gave final approval for the Northern Border Settlement which establishes maximum long-term transportation rates and charges on the Northern Border system effective January 1, 2013. Northern Border’s previous reservation rates were reduced by approximately 11 percent as a result of this settlement.

The Partnership recorded no undistributed earnings from Northern Border for the six months ended June 30, 2013 and 2012.

The summarized financial information for Northern Border is as follows:

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GTN

The Partnership recorded no undistributed earnings from GTN for the six months ended June 30, 2013 and 2012.

The summarized financial information for GTN is as follows:

Bison

The Partnership made an equity contribution to Bison of $6 million in the second quarter of 2013. This amount represents the Partnership’s 25 percent share of a $24 million cash call from Bison to repay inter-affiliate debt primarily related to pipeline construction costs, including reclamation and restoration work.

The Partnership recorded no undistributed earnings from Bison for the six months ended June 30, 2013 and 2012.

The summarized financial information for Bison is as follows:

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NOTE 5                         CREDIT FACILITIES AND LONG-TERM DEBT

The Partnership’s Senior Credit Facility consists of a $500 million senior revolving credit facility with a banking syndicate, maturing November 20, 2017, under which nil was outstanding at June 30, 2013 (December 31, 2012 - $312 million), leaving $500 million available for future borrowing. The nil balance was the result of a repayment from the proceeds of the Partnership’s May 2013 equity offering pending the closing of the 2013 Acquisition (refer to note 13).

The London Interbank Offered Rate (LIBOR) based interest rate on the Senior Credit Facility averaged 1.45 for the three and six months ended June 30, 2013 (2012 – 1.62 and 1.64 percent). The LIBOR-based interest rate was 1.45 percent at June 30, 2013 (2012 – 1.63 percent).

At June 30, 2013, the Partnership was in compliance with its financial covenants, in addition to the other covenants which include restrictions on entering into mergers, consolidations and sales of assets, granting liens, material amendments to the Second Amended and Restated Agreement of Limited Partnership (Partnership Agreement), incurring additional debt and distributions to unitholders.

Series D Senior Notes are secured by Tuscarora’s transportation contracts, supporting agreements and substantially all of Tuscarora’s property. The note purchase agreement contains certain provisions that include, among other items, limitations on additional indebtedness and distributions to partners.

The principal repayments required on the long-term debt are as follows:

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NOTE 6                         PARTNERS’ EQUITY

On May 22, 2013, the Partnership closed a public offering of 8,855,000 common units, including 1,155,000 common units purchased pursuant to the exercise of the underwriters’ option to purchase additional common units, at a price to the public of $43.85 per common unit for gross proceeds of $388 million and net proceeds of $373 million after unit issuance costs. TC PipeLines, GP Inc. (General Partner) maintained its effective two percent general partner interest in the Partnership by contributing $8 million to the Partnership in connection with the offering.

At June 30, 2013, Partners’ Equity included 62,327,766 common units (December 31, 2012 - 53,472,766 common units), representing an aggregate 98 percent limited partner interest in the Partnership (including 5,797,106 common units held by the General Partner and an additional 11,287,725 common units held indirectly by TransCanada), and an aggregate two percent general partner interest. In aggregate, the General Partner’s interests represent an effective 11.1 percent ownership in the Partnership at June 30, 2013 (December 31, 2012 – 12.6 percent).

NOTE 7                         NET INCOME PER COMMON UNIT

Net income per common unit is computed by dividing net income, after deduction of the General Partner’s allocation, by the weighted average number of common units outstanding. The General Partner’s allocation is equal to an amount based upon the General Partner’s effective two percent general partner interest, plus an amount equal to incentive distributions. Incentive distributions are paid to the General Partner if quarterly cash distributions on the common units exceed levels specified in the Partnership Agreement.

Net income per common unit was determined as follows:

NOTE 8                         CASH DISTRIBUTIONS

For the three and six months ended June 30, 2013, the Partnership distributed $0.78 and $1.56 per common unit (2012 – $0.77 and $1.54 per common unit) for a total of $43 million and $85 million, respectively (2012 - $42 million and $84 million). The distributions paid for the three and six months ended June 30, 2013 and 2012 included no incentive distributions to the General Partner.

NOTE 9                         CHANGE IN OPERATING WORKING CAPITAL

NOTE 10                  RELATED PARTY TRANSACTIONS

The Partnership does not have any employees. The management and operating functions are provided by the General Partner. The General Partner does not receive a management fee in connection with its management of the

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Partnership. The Partnership reimburses the General Partner for all costs of services provided, including the costs of employee, officer and director compensation and benefits, and all other expenses necessary or appropriate to the conduct of the business of, and allocable to, the Partnership. Such costs include (i) overhead costs (such as office space and equipment) and (ii) out-of-pocket expenses related to the provision of such services. The Partnership Agreement provides that the General Partner will determine the costs that are allocable to the Partnership in any reasonable manner determined by the General Partner in its sole discretion. Total costs charged to the Partnership by the General Partner were $1 million and $2 million for the three and six months ended June 30, 2013 (2012 – nil and $1 million).

As operator, TransCanada’s subsidiaries provide capital and operating services to our pipeline systems. TransCanada’s subsidiaries incur costs on behalf of our pipeline systems, including, but not limited to, employee salary and benefit costs, and property and liability insurance costs.

Capital and operating costs charged to our pipeline systems for the three and six months ended June 30, 2013 and 2012 by TransCanada’s subsidiaries and amounts payable to TransCanada’s subsidiaries at June 30, 2013 and December 31, 2012 are summarized in the following tables: