U.S. Securities and Exchange Commission
Washington, D.C. 20549
Form 40-F/A
Amendment No. 1
For the fiscal year ended December 31, 2017           Commission File Number 1-8887
(Exact name of Registrant as specified in its charter)
(Province or other jurisdiction of incorporation or organization)
4922, 4923, 4924, 5172
(Primary Standard Industrial Classification Code Number (if applicable))
52 - 2179728
(I.R.S. Employer Identification Number (if applicable))
TransCanada Tower, 450 - 1 Street S.W.
Calgary, Alberta, Canada, T2P 5H1
(403) 920-2000
(Address and telephone number of Registrant's principal executive offices)
TransCanada PipeLine USA Ltd., 700 Louisiana Street, Suite 700
Houston, Texas, 77002-2700; (832) 320-5201
(Name, address (including zip code) and telephone number (including area code)
of agent for service in the United States
Securities registered or to be registered pursuant to Section 12(b) of the Act: None
Securities registered or to be registered pursuant to Section 12(g) of the Act: None
Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act: Debt Securities
For annual reports, indicate by check mark the information filed with this Form:
x Annual information form
o Audited annual financial statements
Indicate the number of outstanding shares of each of the issuer's classes of capital or common stock as of the close of the period covered by the annual report.
At December 31, 2017, 871,760,696 common shares,
which were all owned by TransCanada Corporation, were issued and outstanding.

Indicate by check mark whether the Registrant by filing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934 (the "Exchange Act"). If "Yes" is marked, indicate the file number assigned to the Registrant in connection with such Rule. Yes ¨    82-___________ No x

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Exchange Act during the preceding 12 months (or 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 is an emerging growth company as defined in Rule 12b-2 of the Exchange Act.
Emerging growth company ¨

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the Registrant has elected not to us the extended transition period for complying with any new or revised financial accounting standardsprovided pursuant to Section 13(a) of the Exchange Act.

The term "new or revised financial accounting standard" refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.

The documents (or portions thereof) forming part of this Form 40-F/A are incorporated by reference into the following registration statements under the Securities Act of 1933, as amended:
Registration No.


TransCanada PipeLines Limited ("TCPL") is filing this Form 40-F/A Amendment No. 1 to its annual report on Form 40-F for the year ended December 31, 2017 which was filed with the Securities and Exchange Commission (the "Commission") on February 16, 2018, to include TCPL's Annual information form for the year ended December 31, 2017.
Other than as expressly set forth above, this Form 40-F/A does not, and does not purport to, amend, update, or restate the information in any item of the Form 40-F or reflect any events that have occurred after the Form 40-F was filed.


The Registrant undertakes to make available, in person or by telephone, representatives to respond to inquiries made by the Commission staff, and to furnish promptly, when requested to do so by the Commission staff, information relating to: the securities registered pursuant to Form 40-F; the securities in relation to which the obligation to file an annual report on Form 40-F arises; or transactions in said securities.
We disclose forward-looking information to help current and potential investors understand management's assessment of our future plans and financial outlook, and our future prospects overall.
Statements that are forward-looking are based on certain assumptions and on what we know and expect today and generally include words like anticipate, expect, believe, may, will, should, estimate or other similar words.
Forward-looking statements in this document include information about the following, among other things:
planned changes in our business
our financial and operational performance, including the performance of our subsidiaries
expectations or projections about strategies and goals for growth and expansion
expected cash flows and future financing options available to us
expected dividend growth
expected costs for planned projects, including projects under construction, permitting and in development
expected schedules for planned projects (including anticipated construction and completion dates)
expected regulatory processes and outcomes
expected outcomes with respect to legal proceedings, including arbitration and insurance claims
expected capital expenditures and contractual obligations
expected operating and financial results
the expected impact of future accounting changes, commitments and contingent liabilities
the expected impact of H.R. 1, the Tax Cuts and Jobs Act (U.S. Tax Reform)
expected industry, market and economic conditions.
Forward-looking statements do not guarantee future performance. Actual events and results could be significantly different because of assumptions, risks or uncertainties related to our business or events that happen after the date of this document.
Our forward-looking information is based on the following key assumptions, and subject to the following risks and uncertainties:
planned wind-down of our U.S. Northeast power marketing business
inflation rates and commodity prices
nature and scope of hedging
regulatory decisions and outcomes
interest, tax and foreign exchange rates, including the impact of U.S. Tax Reform
planned and unplanned outages and the use of our pipeline and energy assets
integrity and reliability of our assets
access to capital markets
anticipated construction costs, schedules and completion dates.

Risks and uncertainties
our ability to successfully implement our strategic priorities and whether they will yield the expected benefits
the operating performance of our pipeline and energy assets
amount of capacity sold and rates achieved in our pipeline businesses
the availability and price of energy commodities
the amount of capacity payments and revenues from our energy business
regulatory decisions and outcomes
outcomes of legal proceedings, including arbitration and insurance claims
performance and credit risk of our counterparties
changes in market commodity prices
changes in the political environment
changes in environmental and other laws and regulations
competitive factors in the pipeline and energy sectors
construction and completion of capital projects
costs for labour, equipment and materials
access to capital markets
interest, tax and foreign exchange rates, including the impact of U.S. Tax Reform
cyber security
technological developments
economic conditions in North America as well as globally.
You can read more about these factors and others in reports we have filed with Canadian securities regulators and the Commission.
As actual results could vary significantly from the forward-looking information, you should not put undue reliance on forward-looking information and should not use future-oriented information or financial outlooks for anything other than their intended purpose. We do not update our forward-looking statements due to new information or future events, unless we are required to by law.


Pursuant to the requirements of the Exchange Act, the Registrant certifies that it meets all of the requirements for filing on Form 40-F/A and has duly caused this amendment to the annual report to be signed on its behalf by the undersigned, thereto duly authorized, in the City of Calgary, Province of Alberta, Canada.

Executive Vice-President and Chief Financial Officer
Date: March 12, 2018


Management's discussion and analysis (included on pages 1 through 102 of the TCPL 2017 Management's discussion and analysis and audited consolidated financial statements to shareholders).
2017 Audited consolidated financial statements (included on pages 103 through 175 of the TCPL 2017 Management's discussion and analysis and audited consolidated financial statements to shareholders), including the auditors' report thereon.
TCPL's Annual information form for the year ended December 31, 2017.
Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
A copy of the Registrant's Code of Business Ethics Policy as amended (filed with the Securities and Exchange Commission as part of a Form 6-K report on February 2, 2018 and incorporated by reference herein).
*  previously filed