SUMMARY

This summary, together with the section titled “Questions and Answers About the Transactions and the Special Meeting” immediately preceding this summary, provides a summary of the material terms of the separation, distribution and merger. These sections highlight selected information contained in this proxy statement/prospectus and may not include all the information that is important to you. To better understand the proposed separation, distribution and merger, and the risks related to these transactions, you should read this entire proxy statement/prospectus carefully, including the annexes, as well as those additional documents to which this proxy statement/prospectus refers you. See also “Where You Can Find More Information; Incorporation By Reference.”

Information on ITC (page 73)

ITC Holdings Corp.

27175 Energy Way

Novi, Michigan 48377

(248) 946-3000

ITC Holdings Corp., referred to as ITC, and its subsidiaries are engaged in the transmission of electricity in the United States. ITC’s current operating subsidiaries include International Transmission Company (“ITCTransmission”), Michigan Electric Transmission Company, LLC (“METC”), ITC Midwest LLC (“ITC Midwest”) and ITC Great Plains, LLC (“ITC Great Plains”). ITCTransmission, METC, ITC Midwest and ITC Great Plains are collectively referred to as ITC’s regulated operating subsidiaries. Through ITC’s regulated operating subsidiaries, ITC operates high-voltage systems in Michigan’s Lower Peninsula and portions of Iowa, Minnesota, Illinois, Missouri, Oklahoma and Kansas that transmit electricity from generating stations to local distribution facilities connected to ITC’s systems. ITC’s business strategy is to operate, maintain and invest in transmission infrastructure in order to enhance system integrity and reliability, to reduce transmission constraints and to allow new generating resources to interconnect to ITC’s transmission systems. ITC also is pursuing development projects not within ITC’s existing systems, which are intended to improve overall grid reliability, lower electricity congestion and facilitate interconnections of new generating resources, as well as to enhance competitive wholesale electricity markets. For more information on ITC, see “Information on ITC.”

ITC Midsouth LLC

c/o ITC Holdings Corp.

27175 Energy Way

Novi, Michigan 48377

(248) 946-3000

ITC Midsouth LLC (formerly known as Ibis Transaction Sub LLC), referred to as Merger Sub, is a wholly owned subsidiary of ITC. Merger Sub was organized on December 1, 2011 for the purposes of merging with and into TransCo in the merger. Merger Sub has not carried on any activities other than in connection with the merger agreement and the transactions and approvals contemplated therein.

Information on Entergy (page 80)

Entergy Corporation

639 Loyola Avenue

New Orleans, Louisiana 70113

(504) 576-4000

Entergy Corporation, referred to as Entergy, is an integrated energy company engaged primarily in the electric power production and retail distribution operations. Entergy, through its subsidiaries, owns and operates power plants with approximately 30,000 megawatts of electric generating capacity, including more than 10,000 megawatts of nuclear power, making it one of the nation’s leading nuclear generators. Entergy delivers electricity to 2.8 million utility customers in Arkansas, Louisiana, Mississippi and Texas. Entergy has annual revenues of more than $11 billion and approximately 15,000 employees. Entergy operates its business in two segments: the utility business segment and the Entergy wholesale commodities businesses segment. For more information on Entergy, see “Information on Entergy.”

Mid South TransCo LLC

c/o Entergy Corporation

639 Loyola Avenue

New Orleans, Louisiana 70113

(504) 576-4000

Mid South TransCo LLC, referred to as TransCo, was organized on December 2, 2011 and is currently a wholly owned subsidiary of Entergy. In connection with the separation and distribution, Entergy will cause specified assets and liabilities used in Entergy’s Transmission Business to be transferred to TransCo and then distribute all of the limited liability company interests in TransCo, referred to as the TransCo common units, to Entergy shareholders (excluding any TransCo common units to be contributed to the exchange trust in the event Entergy makes the exchange trust election, as further described below under “—The Exchange Trust”).

The Entergy transmission business, referred to as Entergy’s Transmission Business, consists of the Entergy transmission system, which is comprised of approximately 15,400 circuit miles of transmission lines operated at 69kV to 500kV and approximately 1,400 substations, as well as the employees and assets used to plan, operate and maintain that system. The Entergy transmission system spans portions of Arkansas, Louisiana, Mississippi, Missouri and Texas covering 114,000 square miles. The Entergy transmission system moves high voltage bulk electric power from generating plants of the Utility Operating Companies and other third parties across an interconnected system of transmission lines and substations to distribution points for delivery to wholesale customers such as municipalities and cooperatives, as well as to the approximately 2.8 million retail customers of the Utility Operating Companies. For more information on Entergy’s Transmission Business, see “Information on Entergy’s Transmission Business.”

The Transactions (See “The Transactions” beginning on page 108).

On December 4, 2011, ITC and Entergy agreed to enter into transactions to effect the transfer of Entergy’s Transmission Business to ITC. These transactions provide for the separation of Entergy’s Transmission Business into TransCo, the distribution of TransCo and the subsequent merger of Merger Sub with and into TransCo, with TransCo surviving as a wholly owned subsidiary of ITC. As a result of and immediately following these transactions, Entergy shareholders (and, if applicable, the exchange trust) will collectively own approximately 50.1% of ITC common stock on a “fully diluted basis,” and existing ITC shareholders will collectively own approximately 49.9% of ITC common stock on a “fully diluted basis” (subject to adjustment in limited circumstances as provided in the merger agreement and excluding any ITC equity awards issued to employees of Entergy’s Transmission Business who become employees of TransCo). In no event will Entergy shareholders (and, if applicable, the exchange trust) hold less than 50.1% of the outstanding common stock of ITC immediately after the merger. Entergy shareholders will retain their shares of Entergy common stock.

In order to effect the separation, distribution and merger, ITC, Merger Sub, Entergy and TransCo entered into the merger agreement; Entergy, ITC, TransCo, each of Entergy’s Utility Operating Companies and ESI entered into the separation agreement and Entergy, ITC and TransCo entered into the employee matters agreement. In addition, ITC, Entergy, TransCo or their respective affiliates will also enter into a series of

ancillary agreements in connection with the transactions. These agreements, which are described in greater detail in this proxy statement/prospectus, will govern the relationship among ITC, Entergy, TransCo and their respective affiliates after the separation and distribution. For a more complete discussion of the transaction agreements, see “The Merger Agreement,” “The Separation Agreement,” and “Additional Agreements.”

Transaction Timeline (See “The Transactions—Transaction Timeline” beginning on page 108).

Below is a step-by-step list illustrating the material events relating to the separation, distribution and merger:

Step #1—Entergy Exchangeable Debt. At least fourteen (14) days prior to the debt exchange, Entergy will issue or unrelated creditors will purchase Entergy exchangeable debt (as described below under “—The Financings”). The amount of Entergy exchangeable debt to be issued or purchased is expected to be $575 million, but in any case will be of equal aggregate principal amount as the TransCo debt securities.

Step #2—ITC Financing, ITC Special Dividend and/or Share Repurchase. Prior to the merger, ITC may, in its sole discretion, elect to (i) declare a one-time special dividend payable to pre-merger ITC shareholders, (ii) effect a share repurchase of ITC common stock or (iii) undertake a combination of a one-time special dividend and share repurchase of ITC common stock. The aggregate amount payable to ITC shareholders in connection with a one-time special dividend or share repurchase or a combination of both will not exceed $700 million. Prior to the merger, ITC expects to enter into debt financings to fund any such transactions.

Step #3—Entergy Corporate Reorganization. On or prior to the separation date, Entergy, the Utility Operating Companies and other Entergy affiliates will effectuate a series of restructuring transactions. Such restructuring transactions will include (i) each Utility Operating Company redeeming its outstanding preferred equity interests, if any, and (ii) each Utility Operating Company merging with and into a newly formed, directly or indirectly, wholly owned limited liability company of Entergy with such limited liability company surviving.

Step #4—TransCo Subs Financing; Utility Operating Companies Contribution of Transmission Assets. The TransCo Subs will effectuate the TransCo Subs Financing (as described below under “—The Financings”). The aggregate amount of the TransCo Subs Financing is expected to be $1.2 billion. Simultaneously with or immediately after the TransCo Subs Financing, each Utility Operating Company (now in limited liability company form) will transfer its respective specified transmission assets and liabilities to its respective TransCo Sub and, as part of the consideration for such transfer, each Utility Operating Company will receive its respective portion of the net proceeds of the TransCo Sub Financing.

Step #5—Distribution of TransCo Subs to Entergy. All of the equity interests in each respective TransCo Sub will be distributed to Entergy.

Step #6—Entergy Contribution. Entergy will contribute to TransCo all of the equity interests of each TransCo Sub and cash in exchange for (i) the number of TransCo common units determined pursuant to the merger agreement and (ii) the TransCo debt securities (as described below under “—The Financings”).

Step #7—Transfer of ESI Assets to TransCo or one or more TransCo Subs. Using the cash received in Step #6, TransCo or one or more TransCo Subs will purchase certain assets owned by ESI.

Step #8—The Distribution. Entergy will effect the distribution of the TransCo common units to the Entergy shareholders through a spin-off, split-off exchange offer or a combination of a spin-off and split-off exchange offer. At the closing of the distribution, the TransCo common units will be delivered to the distribution agent, who will hold such shares for the benefit of Entergy shareholders. In the event Entergy makes the exchange trust election, Entergy will contribute the TransCo common units to be held by the exchange trust at or prior to the distribution.

Step #9—The Debt Exchange. At the time of the separation, it is expected that Entergy will effect an exchange of the TransCo debt securities for the Entergy exchangeable debt.

Step #10—The Merger. Merger Sub will be merged with and into TransCo with TransCo surviving the merger as a wholly owned subsidiary of ITC. In the merger, the TransCo common units held by the distribution agent will be converted into the number of shares of ITC common stock such that immediately after the merger, Entergy shareholders (and, if applicable, the exchange trust) will collectively own approximately 50.1% of ITC common stock on a “fully diluted basis,” and existing ITC shareholders will collectively own approximately 49.9% of ITC common stock on a “fully diluted basis” (subject to adjustment in limited circumstances as provided in the merger agreement and excluding any ITC equity awards issued to employees of Entergy’s Transmission Business who become employees of TransCo). In no event will Entergy shareholders (and, if applicable, the exchange trust) hold less than 50.1% of the outstanding common stock of ITC immediately after the merger.

Step #11—Distribution of ITC Common Stock to Entergy Shareholders. The distribution agent will distribute shares of ITC common stock and cash in lieu of fractional share interests to Entergy shareholders on a pro rata (with certain limited exceptions) basis in accordance with the terms of the merger agreement (assuming Entergy elects to effectuate the distribution through a spin-off).

The Separation and Distribution (See “The Transactions—The Separation and Distribution” beginning on page 112).

Prior to the merger of Merger Sub with and into TransCo, Entergy will undergo an internal restructuring to separate and consolidate Entergy’s Transmission Business under TransCo pursuant to the terms of the separation agreement.

On or prior to the separation date, Entergy, the Utility Operating Companies and other Entergy affiliates will effectuate a series of restructuring transactions. Such restructuring transactions will include (i) each Utility Operating Company redeeming its outstanding preferred equity interests, if any, and (ii) each Utility Operating Company merging with and into a newly formed, directly or indirectly, wholly-owned limited liability company of Entergy with such limited liability company surviving.

Simultaneously with or immediately after the TransCo Subs Financing, each Utility Operating Company will transfer its respective specified transmission assets and liabilities to its respective TransCo Sub, referred to as the Utility Operating Companies contributions. In consideration of the Utility Operating Companies contributions, each Utility Operating Company will receive the net proceeds of the respective TransCo Sub Financing.

Immediately thereafter, the Utility Operating Companies and certain other intermediate holding companies of Entergy will distribute the equity interests of the TransCo Subs so that Entergy will be the direct holder of the equity interests of each TransCo Sub. Immediately thereafter, Entergy will contribute cash to certain TransCo Subs, and such TransCo Subs will purchase certain assets of ESI.

Immediately thereafter, Entergy will contribute all the equity interests in each TransCo Sub to TransCo in exchange for (i) a number of TransCo common units not to be less than the number which will be necessary for the Entergy shareholders (and, if applicable, the exchange trust) immediately prior to the merger to constitute the holders of at least 50.1% of the outstanding ITC common stock immediately following the merger and (ii) TransCo debt securities.

Pursuant to the merger agreement and prior to the merger, Entergy will distribute 100% of the TransCo common units (excluding any TransCo common units to be contributed to the exchange trust in the event Entergy makes the exchange trust election) to Entergy’s shareholders through a spin-off, a split-off exchange offer or a combination of the two, referred to as the distribution.

If the distribution includes a spin-off, each record holder of Entergy common stock (other than restricted Entergy common stock) will be entitled to receive its pro rata share of TransCo common units subject to the spin-off.

If the distribution includes a split-off exchange offer of TransCo common units for currently outstanding shares of Entergy common stock, in the event that there are unsubscribed TransCo common units resulting from such split-off exchange offer, Entergy will distribute them to Entergy shareholders, a transaction referred to as the clean-up spin-off. In a clean-up spin-off, each record holder of Entergy common stock (other than Entergy restricted common stock) will be entitled to receive its pro rata share of TransCo common units subject to the clean-up spin-off.

Conditions to the Separation (See “The Separation Agreement—Conditions to the Separation” beginning on page 194).

The obligations of Entergy to effect the separation pursuant to the separation agreement are subject to fulfillment (or waiver by Entergy) at or prior to the separation date of the conditions that:

The Merger; Merger Consideration (See “The Transactions—The Merger” beginning on page 113 and “The Transactions—Calculation of the Merger Consideration” beginning on page 113).

In accordance with the merger agreement and Delaware law, immediately following the distribution, Merger Sub will merge with and into TransCo. As a result of the merger, the separate corporate existence of Merger Sub will cease and TransCo will continue as the surviving entity and will become a wholly-owned direct subsidiary of ITC. Following the merger, ITC will continue the combined business operations of TransCo and ITC.

The merger agreement provides that each TransCo common unit issued and outstanding immediately before the effective time of the merger (which calculation is described below) will automatically convert at the effective time of the merger into the right to receive one fully paid and nonassessable share of ITC common stock. However, each TransCo common unit that is owned, directly or indirectly, by ITC or Merger Sub or held by TransCo, immediately prior to the effective time of the merger, will be automatically cancelled at the effective

time of the merger. Holders of Entergy common stock (who following the distribution will have become holders of TransCo common units) will not be required to pay for the shares of ITC common stock they receive and will also retain all of their Entergy common stock. Existing shares of ITC common stock will remain outstanding.

No fractional shares of ITC common stock will be issued in the merger to holders of fractional TransCo common units. Instead, within 30 business days following the effective time of the merger, the exchange agent will aggregate all fractional shares of ITC common stock and sell them on behalf of those Entergy shareholders who otherwise would be entitled to receive a fractional share of ITC common stock. Those Entergy shareholders will then receive a cash payment in an amount equal to their pro rata share of the total net proceeds of those sales. The receipt of cash in lieu of fractional shares generally will be taxable to the recipient shareholders as described in “Material United States Federal Income Tax Consequences of the Transactions.”

As further described above under “—The Separation and Distribution” and under “The Merger Agreement,” in the separation, TransCo will issue to Entergy a number of TransCo common units equal to the sum of:

The term “fully diluted basis” means Entergy and ITC’s estimate of the number of shares of ITC common stock that will be outstanding on the closing date of the merger, together with the estimated amount of shares of ITC common stock that will be issuable on the closing date of the merger upon the exercise of any options, rights or units based on the treasury stock method (other than the shares of ITC common stock issued or to be issued in the merger, including pursuant to the employee matters agreement) as further detailed in the merger agreement.

The “estimation date” will be the nearest reasonably practicable date prior to the last trading day that ends at least 20 trading days prior to the date the distribution will be expected to occur, as mutually agreed by Entergy and ITC.

The “aggregate disqualified share number” means ITC’s and Entergy’s best estimate of the number of shares of ITC common stock issuable upon the conversion of Entergy stock options and restricted shares to ITC stock options and restricted shares that are reasonably likely to be treated as being issued as part of a plan or series of related events for U.S. federal income tax purposes that would cause the distribution to be treated as a taxable event.

The merger agreement also provides that the number of TransCo common units to be issued to Entergy will in no event be less than that number which will be necessary for the Entergy shareholders (and, if applicable, the exchange trust) immediately prior to the merger to constitute the holders of at least 50.1% of the outstanding common stock immediately following the merger, as determined under U.S. federal income tax rules to ensure that the spin-off or split-off exchange offer is not taxable to Entergy.

Conditions to the Merger (See “The Merger Agreement—Conditions to the Merger” beginning on page 180).

As more fully described in this proxy statement/prospectus, the obligations of each of the parties to effect the closing of the merger are subject to the satisfaction or waiver of a number of conditions, including those described below.

Mutual Conditions. The obligations of Entergy, TransCo, Merger Sub and ITC to effect the merger are subject to the satisfaction (or waiver by all parties) of the following conditions:

ITC Conditions. The obligation of each of ITC and Merger Sub to effect the merger is further subject to the satisfaction of the following conditions (each of which is for the exclusive benefit of ITC and Merger Sub and may be waived by ITC):

Entergy Conditions. The obligation of each of Entergy and TransCo to effect the merger is further subject to the satisfaction of the following conditions (each of which is for the exclusive benefit of Entergy and TransCo and may be waived by Entergy):

The Exchange Trust (See “The Transactions—Exchange Trust” beginning on page 117).

Pursuant to the terms of the merger agreement, Entergy may elect, at least 30 business days prior to the closing of the merger to retain up to the number of TransCo common units that would convert in the merger to up to 4.9999% of the total number of shares of ITC common stock outstanding immediately following the consummation of the merger that otherwise would have been distributed in the distribution, such election is referred to as the exchange trust election. If Entergy makes an exchange trust election, and subject to the conditions in the merger agreement, Entergy, TransCo, ITC and a trustee will enter into a trust agreement, referred to as the exchange trust agreement. Under the terms of the exchange trust agreement, at the time of the distribution, Entergy will transfer such TransCo common units to an irrevocable Delaware trust, referred to as the exchange trust. The TransCo common units transferred to the exchange trust will not be distributed to Entergy shareholders in the distribution and, at the closing of the merger, will subsequently be converted into ITC common stock in the merger. The trustee of the trust will own and hold legal title to the TransCo common units or ITC common stock. Pursuant to the exchange trust agreement, the exchange trust will hold the shares for the benefit of Entergy and Entergy shareholders; provided, however, in no event will the ITC common stock held by the exchange trust be transferred to Entergy. Upon delivery of notice by Entergy, the trustee will conduct an exchange offer whereby Entergy shareholders may exchange Entergy common stock for the ITC common stock held by the exchange trust pursuant to irrevocable terms contained in the trust agreement at the time it is entered into, referred to as the exchange trust exchange offer. Pursuant to the exchange trust agreement, any ITC common stock remaining in the exchange trust after six months following the completion of the merger will be distributed to Entergy shareholders pro rata. If Entergy makes an exchange trust election, Entergy, ITC and the trustee of the exchange trust will also enter into a registration rights agreement whereby ITC will provide the trustee and Entergy certain registration rights with respect to the retained equity. The purpose of the exchange trust is to permit an exchange offer with Entergy shareholders to occur when the trading market for the combined company’s common stock has settled following the merger. This delayed exchange offer, if elected by Entergy, is an option to help Entergy efficiently manage its post-transaction capital structure and improve cash flow and credit metrics. Upon the consummation of a successful exchange offer by the trust, there would be fewer outstanding shares of Entergy common stock, as those shares would have been exchanged for the shares of ITC common stock held by the trust. Consequently, a successful delayed exchange offer would permit Entergy to reduce its common shares outstanding and aggregate cash dividends paid and as a result could improve Entergy’s available cash flow and credit metrics.

For additional information on the exchange trust agreement and the registration rights agreement, see “Additional Agreements—Exchange Trust Agreement” and “Additional Agreements—Registration Rights Agreement.”

Opinions of ITC’s Financial Advisors (See “The Transactions—Opinion of J.P. Morgan” beginning on page 133 and “The Transactions—Opinion of Barclays” beginning on page 141).

Opinion of J.P. Morgan

In deciding to approve the merger, the merger agreement, the separation agreement, the employee matters agreement and the other transactions contemplated thereby, the ITC board of directors considered the opinion delivered to it on December 4, 2011 by J.P. Morgan Securities LLC, its financial advisor, which we refer to herein as J.P. Morgan, that, as of the date of the opinion, and based upon and subject to the various factors,

procedures, assumptions, limitations and qualifications set forth in its opinion, the aggregate consideration (consisting of the issuance of one share of ITC common stock in exchange for each TransCo common unit, plus the payment of cash in lieu of any fractional shares) to be paid by ITC in the proposed transactions was fair, from a financial point of view, to ITC. The full text of the written opinion of J.P. Morgan, dated December 4, 2011, which sets forth the assumptions made, matters considered and qualifications and limitations on the opinion and the review undertaken by J.P. Morgan is attached as Annex D to this proxy statement/prospectus and is incorporated by reference herein in its entirety. You are encouraged to read the opinion and the description included in this proxy statement/prospectus carefully in their entirety. The summary and the description of the opinion are qualified in their entirety by reference to the full text of the opinion. J.P. Morgan’s opinion is limited to the fairness, from a financial point of view, to ITC of the aggregate consideration to be paid by ITC in the proposed transactions and J.P. Morgan expressed no opinion as to any other matter. The opinion does not constitute a recommendation to any shareholder as to how such shareholder should vote with respect to the proposed transactions or any other matter. See “The Transactions—Opinion of J.P. Morgan.”

Opinion of Barclays

In deciding to approve the merger, the merger agreement, the separation agreement, the employee matters agreement and the other transactions contemplated thereby, the ITC board of directors considered the opinion, dated December 4, 2011, of Barclays Capital Inc., referred to herein as Barclays, as to the fairness, from a financial point of view and as of the date of such opinion and subject to the qualifications, limitations and assumptions stated in such opinion, to ITC of the exchange ratio in the merger, which means the right, pursuant to the merger, of holders of TransCo units to receive one share of ITC common stock in exchange for each TransCo common unit they hold. The full text of Barclays’ written opinion is attached as Annex E to this proxy statement/prospectus and is incorporated herein by reference. The written opinion sets forth, among other things, the assumptions made, procedures followed, factors considered and limitations on the review undertaken by Barclays in rendering its opinion. This summary of Barclays’ written opinion is qualified in its entirety by reference to the full text of the opinion. Barclays’ opinion, the issuance of which was approved by Barclays’ fairness opinion committee, was addressed to the ITC board of directors for its use and benefit in connection with its evaluation of the exchange ratio and related only to the fairness, from a financial point of view, to ITC of the exchange ratio in the merger. Barclays was not requested to opine as to, and its opinion did not in any manner address, ITC’s underlying business decision to proceed with or effect the transactions or the likelihood of consummation of the transactions. The opinion was not intended to be and does not constitute a recommendation to any shareholder of ITC as to how such shareholder should vote or act with respect to the transactions or any related matter. See the section entitled “The Transactions—Opinion of Barclays.”

Board of Directors and Management of ITC Following the Merger (See “Information on ITC—Directors and Executive Officers of ITC Before and After the Merger” beginning on page 74 and “The Transactions—Board of Directors and Management of ITC Following the Merger” beginning on page 150).

The directors of ITC immediately prior to the closing of the merger are expected to be the directors of ITC immediately following the closing of the merger, except that at the effective time of the merger, ITC has agreed that there will be at least two vacancies on the ITC board of directors (either through resignations of existing directors, by increasing the size of the board or a combination thereof) pursuant to the merger agreement, which vacancies will be filled immediately after the effective time of the merger with two independent directors nominated by ITC’s nominating/corporate governance committee. Among other qualifications, nominees are expected to have transmission industry knowledge and familiarity with the region in which Entergy operates. Entergy will be entitled to offer to ITC’s nominating/corporate governance committee suggestions on candidates to fill such vacancies in connection with the search process. Any decision with respect to Entergy’s candidates, however, will be made solely by ITC’s nominating/corporate governance committee.

The executive officers of ITC immediately prior to the closing of the merger are expected to be the executive officers of ITC immediately following the closing of the merger. The merger agreement provides that ITC and TransCo will take all necessary action to appoint certain specified individuals to management positions at ITC or TransCo as of the effective time of the merger.

Interests of Certain Persons in the Merger (See “The Transactions—Interests of Certain Persons in the Merger” beginning on page 151).

In considering the ITC board of directors’ determination to approve the merger agreement, the merger and the other transactions contemplated by the merger agreement and to recommend that ITC shareholders vote in favor of the merger proposals, ITC shareholders should be aware that certain officers and directors of ITC may have certain interests in the merger and related transactions that are different from, or in addition to, the interests of ITC shareholders, see “The Transactions—Interests of Certain Persons in the Merger.” The ITC board of directors was aware of these interests and considered them, among other matters, in approving the merger agreement, the merger and the other transactions contemplated by the merger agreement, including the acceleration of certain vesting terms under ITC’s 2006 Long Term Incentive Plan.

Except with respect to the treatment of Entergy restricted common stock, the directors and officers of Entergy and TransCo will receive no extra or special benefit that is not shared on a pro rata basis by all other Entergy shareholders in connection with the transactions. For more information on the treatment of Entergy restricted common stock, see “The Transactions—Effects of the Distribution and the Merger on Entergy Equity Awards/Plans.”

Regulatory Approvals (See “The Transactions—Regulatory Approvals” beginning on page 155, “The Merger Agreement—Antitrust Matters” beginning on page 175 and “The Merger Agreement—Efforts to Close” beginning on page 175).

As further described in this proxy statement/prospectus, to complete the separation, the distribution and the merger, there are certain filings, notices and waiting periods required in order for ITC and Entergy to obtain required authorizations, approvals and/or consents from a number of federal and state public utilities, antitrust and other regulatory authorities, including the FERC, the Nuclear Regulatory Commission, the Arkansas Public Service Commission, the Louisiana Public Service Commission, the Mississippi Public Service Commission, the Public Utility Commission of Texas, the City Council for the City of New Orleans, and the Nuclear Regulatory Commission (the “NRC”), as well as the expiration of the applicable waiting period under the HSR Act. For additional information, see “The Transactions—Regulatory Approvals.”

As further described in this proxy statement/prospectus, the merger agreement generally provides that Entergy and ITC will file all required notifications under the HSR Act with the Federal Trade Commission (the “FTC”) and the Department of Justice (the “DOJ”). The parties made such filings on December 14, 2012. Each party has agreed, subject to certain limitations, to use its reasonable best efforts to obtain early termination of any waiting period under the HSR Act and supply each other, the FTC and the DOJ with any information reasonably required in connection with such filings. The waiting period under the HSR Act expired on January 14, 2013. In addition, the merger agreement generally provides that Entergy and ITC will use their respective reasonable best efforts (as specified in the merger agreement and subject to certain exceptions specified therein) to consummate the transactions, including using reasonable best efforts to file any applications, notices, registrations, filings, reports, petitions and other documents required to be filed with any governmental authority necessary or advisable to consummate the transactions, obtain each required approval, consent, ratification, permission and waiver of authorization from governmental authorities and parties to any material contractual obligations, cooperate with and provide notice to each other and lift any restraint, injunction or other legal bar to the transactions. For additional information, see “The Merger Agreement—Antitrust Matters” and “The Merger Agreement—Efforts to Close.”

No Dissenters’ Rights (See “The Transactions—No Dissenters’ Rights” beginning on page 160).

ITC shareholders will not be entitled to dissenters’ rights under the MBCA in connection with the merger.

The Financings (See “The Financings” beginning on page 162 and “The Separation Agreement—The Financings” beginning on page 192).

Entergy Exchangeable Debt. At least fourteen days prior to the debt exchange, Entergy will issue debt to one or more unrelated creditors or one or more unrelated creditors will purchase existing Entergy corporate debt, in each case, such debt is referred to as Entergy exchangeable debt. As described below, assuming that the desired private letter ruling from the IRS with respect to the financings is obtained, the amount of Entergy exchangeable debt to be issued or purchased is expected to be $575 million, but in any case will be of equal aggregate principal amount as the TransCo debt securities.

Issuance of TransCo Debt Securities. In partial consideration for the equity interests of the TransCo Subs contributed by Entergy to TransCo in the Entergy contribution, TransCo will issue to Entergy debt of TransCo, referred to as TransCo debt securities, in an aggregate principal amount, when combined with the TransCo Subs Financing, of $1.775 billion (as may be adjusted pursuant to the merger agreement), referred to as the transaction maximum principal amount. It is currently expected that the aggregate principal amount of the TransCo debt securities will be $575 million, but in any case will be of equal aggregate principal amount as the Entergy exchangeable debt.

The Debt Exchange. At the time of the separation, it is expected that Entergy will effect an exchange with the holders of the Entergy exchangeable debt for the TransCo debt securities previously issued to Entergy. In the exchange (should the exchange occur), the unrelated creditor or creditors that hold the Entergy exchangeable debt will receive the TransCo debt securities and Entergy will receive the Entergy exchangeable debt. TransCo will not receive any proceeds from the issuance of the TransCo debt securities or the debt exchange.

Working Capital Facility. At the request of ITC, Entergy will use its reasonable best efforts to cause TransCo to arrange a working capital revolving credit facility in a principal amount mutually determined by ITC and Entergy. TransCo will not draw down on the working capital facility without the consent of ITC.

TransCo Subs Financing. Entergy will use its reasonable best efforts to cause the TransCo Subs to arrange a 366-day bridge facility, referred to as the TransCo Subs Financing, based on a targeted capital structure for each TransCo Sub of 40% debt and 60% equity (provided that if the desired private letter ruling from the Internal Revenue Service with respect to the financings cannot be obtained without adjusting the principal amount of the TransCo Subs Financing, then the parties will have the right to increase or decrease the principal amount of the TransCo Subs Financing to an amount equal to the aggregate tax basis of the transmission assets). It is expected that after the merger the TransCo subs will issue first mortgage bonds to refinance the bridge facility. Assuming the desired private letter ruling from the IRS with respect to the financings is obtained, the aggregate amount of the TransCo Subs Financing is expected to be $1.2 billion. No TransCo Sub will retain any proceeds from the TransCo Subs Financing.

For more information on the contractual obligations of Entergy, TransCo and ITC with respect to the financings, see “The Separation Agreement—Financings.”

ITC Recapitalization. Prior to the merger, ITC may, in its sole discretion, elect to (i) declare a one-time special dividend payable to pre-merger ITC shareholders, (ii) effect a share repurchase of ITC common stock, or (iii) undertake a combination of a one-time special dividend and share repurchase of ITC common stock. The aggregate amount payable to ITC shareholders in connection with a one-time special dividend or share

repurchase or a combination of both will not exceed $700 million. Such transactions are expected to be funded by debt securities to be issued by ITC prior to the merger. The decision regarding the form of the recapitalization remains in the sole discretion of the ITC board of directors and will be made closer to the closing of the merger.

Termination (See “The Merger Agreement—Termination of the Merger Agreement” beginning on page 182).

The merger agreement may be terminated at any time prior to the closing date of the merger by the mutual written consent of ITC and Entergy. In addition, either Entergy or ITC may terminate the merger agreement prior to the closing date of the merger if:

In addition, Entergy may terminate the agreement if:

Termination Fees (See “The Merger Agreement—Termination Fee” beginning on page 183).

ITC has agreed to pay Entergy a termination fee of $113,570,800 in the event that the merger agreement is terminated:

Required Vote (See “The Special Meeting of ITC Shareholders—Required Vote” beginning on page 69).

The affirmative vote of a majority of the outstanding shares of ITC common stock entitled to vote at the special meeting is required to approve the merger agreement. The affirmative vote of a majority of the outstanding shares of ITC common stock entitled to vote at the special meeting is required to approve the proposal to amend the amended and restated articles of incorporation of ITC to increase the number of authorized shares of ITC common stock. The affirmative vote of a majority of the votes cast, in person or by proxy, at the special meeting by holders of shares of ITC common stock is required to approve the proposal to issue shares of ITC common stock pursuant to the merger agreement. In accordance with Section 14A of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), ITC is providing its shareholders with the opportunity to approve, by non-binding, advisory vote, certain compensation payments for ITC’s named executive officers in connection with the merger, as reported in the section of this proxy statement/prospectus entitled “Advisory Vote on Merger-Related Compensation for ITC’s Named Executive Officers.” The affirmative vote of a majority of the votes cast, in person or by proxy, at the special meeting by holders of shares of ITC common stock is required to approve this merger-related executive compensation proposal. The affirmative vote of a majority of the votes cast, in person or by proxy, at the special meeting by holders of shares of ITC common stock is required to approve the proposal to permit adjournment of the special meeting.

The approval of each of the merger proposals (which are the proposal to approve the merger agreement, the amendment of the articles of incorporation proposal and the stock issuance proposal) is conditioned upon the approval of each of the other merger proposals, and the merger will not occur unless all of the merger proposals are approved.

No vote of Entergy shareholders is required or being sought in connection with either the spin-off or the split-off exchange offer, the merger or the other transactions described in this proxy statement/prospectus.

Voting by ITC Executive Officers and Directors (See “The Special Meeting of ITC Shareholders—Certain Ownership of ITC Common Stock” beginning on page 72).

As of February 22, 2013, ITC’s executive officers and directors beneficially owned 1,571,571 shares of ITC common stock, representing approximately 3.01% of the shares outstanding as of such date. ITC currently expects that each of its directors and executive officers will vote their shares of ITC common stock in favor of all proposals, although none of them has entered into an agreement requiring them to do so.

Material United States Federal Income Tax Consequences of the Transactions (See “Material United States Federal Income Tax Consequences of the Transactions” beginning on page 230).

Entergy shareholders are not expected to recognize any gain or loss for U.S. federal income tax purposes as a result of the separation, distribution, merger, exchange trust exchange offer and mandatory trust distribution except for any gain or loss attributable to the receipt of cash in lieu of a fractional share of ITC common stock in the merger, exchange trust exchange offer, or mandatory trust distribution or cash, if any, received by an Entergy shareholder in addition to the shares of ITC common stock in an exchange trust exchange offer or mandatory trust distribution (other than cash received instead of fractional shares). ITC shareholders will not receive any stock or other consideration in respect of their ITC common stock pursuant to the aforementioned transactions and accordingly are not expected to realize any gain or loss as a result of such transactions (excluding any effects of the ITC $700 million recapitalization in the form of a one-time special dividend and/or share repurchase).

Risk Factors (See “Risk Factors” beginning on page 53).

ITC and Entergy shareholders should carefully consider the matters described in the section “Risk Factors,” as well as other information included in this proxy statement/prospectus and the other documents to which they have been referred.

SUMMARY HISTORICAL AND PRO FORMA FINANCIAL DATA

The following summary historical combined financial data of Entergy’s Transmission Business, summary historical consolidated financial data of ITC, summary unaudited condensed combined pro forma financial data of ITC and comparative historical and pro forma per share data of ITC are being provided to help you in your analysis of the financial aspects of the transaction. You should read this information in conjunction with the financial information included elsewhere and incorporated by reference in this document. See “Where You Can Find More Information; Incorporation By Reference,” “Information on ITC,” “Information on Entergy’s Transmission Business” and “Selected Financial Statements Data.”

Summary of Historical Combined Financial Data of Entergy’s Transmission Business

Entergy’s Transmission Business’ combined statement of income data for the three years ended December 31, 2011, 2010 and 2009 and the combined balance sheet data as of December 31, 2011 and 2010 have been derived from Entergy’s Transmission Business’ audited combined financial statements, included elsewhere in this document. The summary combined financial data below is not necessarily indicative of the results that may be expected for any future period. This information is only a summary and should be read in conjunction with the financial statements of Entergy’s Transmission Business and the accompanying notes and the related “Management’s Discussion and Analysis of Financial Condition and Results of Operations for Entergy’s Transmission Business” thereto included elsewhere in the document.

The financial information of Entergy’s Transmission Business included in this document has been derived from the consolidated financial statements and accounting records of Entergy and reflects assumptions and allocations made by Entergy. The financial position, results of operations and cash flows of Entergy’s Transmission Business presented may be different from those that would have resulted had Entergy’s Transmission Business been operated as a stand-alone company. Additionally, the financial position, results of operations and cash flows of Entergy’s Transmission Business presented reflects its existing state and local jurisdictional rate regulation as a component of the Utility Operating Companies as compared to the FERC rate regulation expected for Entergy’s Transmission Business under ITC’s ownership. As a result, the historical financial information of Entergy’s Transmission Business is not a reliable indicator of future results. See “Risk Factors.”

Summary of Historical Consolidated Financial Data of ITC

ITC’s summary historical consolidated financial data presented below have been derived from, and should be read in conjunction with ITC’s consolidated financial statements and the accompanying notes and the related “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections in ITC’s Annual Report on Form 10-K, as amended by the Annual Report on Form 10-K/A, for the year ended December 31, 2011 (which is incorporated herein by reference). The data shown below is not necessarily indicative of results to be expected for any future period. To find where you can obtain copies of ITC’s documents that have been incorporated by reference, see “Where You Can Find More Information; Incorporation By Reference.”

Summary Unaudited Condensed Combined Pro Forma Financial Data

The summary unaudited condensed combined pro forma financial data presented below have been prepared by ITC and are being provided for illustrative purposes only and are not necessarily indicative of what the operating results or financial position of ITC or Entergy’s Transmission Business would have been had the transaction been completed at the beginning of the periods or on the dates indicated, nor are they necessarily indicative of any future operating results or financial position. The results of operations and cash flows of the acquired business reflect its existing state and local jurisdictional rate regulation as a component of the Utility Operating Companies, as compared to the FERC rate regulation expected for Entergy’s Transmission Business under ITC’s ownership. The pro forma financial statements do not reflect the impact of transitioning Entergy’s

Transmission Business to FERC rate regulation under ITC ownership. The selected unaudited pro forma combined consolidated financial information has been derived from, and should be read in conjunction with, the Unaudited Pro Forma Condensed Combined Consolidated Financial Statements and related notes beginning on page 41 of this proxy statement/prospectus.

Comparative Historical and Pro Forma Per Share Data

The following tables set forth historical and pro forma per share data of ITC. The ITC historical data have been derived from, and should be read in conjunction with, the audited consolidated financial statements of ITC and the related notes thereto included in ITC’s Annual Report on Form 10-K, as amended by the Annual Report on Form 10-K/A, for the year ended December 31, 2011 and the unaudited financial statements of ITC and related notes thereto included in ITC’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2012, each of which is incorporated by reference into this document.

This summary of comparative historical and pro forma per share data is being provided for illustrative purposes only and is not necessarily indicative of the results that would have been achieved had the transaction been completed during the period presented, nor are they necessarily indicative of any future results. ITC and Entergy’s Transmission Business may have performed differently had the transaction occurred prior to the period presented. The results of operations and cash flows of the acquired business reflect its existing state and local jurisdictional rate regulation as a component of the Utility Operating Companies, as compared to the FERC rate regulation expected for Entergy’s Transmission Business under ITC’s ownership. The pro forma financial

statements do not reflect the impact of transitioning Entergy’s Transmission Business to FERC rate regulation under ITC ownership. You should not rely on the pro forma per share data presented as being indicative of the results that would have been achieved had ITC and Entergy’s Transmission Business been combined during the period presented or of the future results of ITC following the transaction.

The following table presents certain historical and pro forma per share data for ITC:

HISTORICAL MARKET PRICE DATA AND DIVIDEND INFORMATION

Historical Market Price Data

Historical market price data for TransCo has not been presented because TransCo is currently a wholly-owned subsidiary of Entergy and its equity interests are not publicly traded.

ITC common stock is listed and traded on the NYSE under the symbol “ITC.” The following table sets forth, for the periods indicated, the high and low sales prices per share of ITC common stock, as reported on the NYSE. In addition, the table also sets forth the quarterly cash dividends per share declared by ITC with respect to its common stock. On February 22, 2013, the last practicable trading day prior to the date of this proxy statement/prospectus, there were 52,272,168 shares of ITC common stock outstanding.

The following table presents the last reported sale price of a share of ITC common stock, as reported on the NYSE on December 2, 2011, the last full trading day prior to the public announcement of the proposed transactions, and on February 22, 2013, the last practicable trading day prior to the date of this proxy statement/prospectus:

Dividend Policy

The declaration and payment of dividends is subject to the discretion of the ITC board of directors and depends on various factors, including ITC’s net income, financial condition, cash requirements, future prospects and other factors deemed relevant by the ITC board of directors. The debt agreements to which ITC is a party

contain financial covenants that could limit ITC’s ability to pay dividends, as well as covenants that prohibit ITC from paying dividends if ITC is in default under its revolving credit facilities. The ITC board of directors intends to adjust the dividend rate from time to time, subject to prevailing business conditions, applicable restrictions on dividend payments, the availability of capital resources and ITC’s investment opportunities.

In connection with the transactions, prior to closing the merger, ITC expects to effectuate a $700 million recapitalization, which may take the form of a one-time special dividend to ITC’s pre-merger shareholders, a repurchase of ITC common stock from the ITC shareholders, or a combination of a one-time special dividend and a share repurchase. The decision regarding the form of the recapitalization remains in the sole discretion of the ITC board of directors and will be made closer to the closing of the merger.

Following the date of the merger agreement and prior to the effective time of the merger, ITC will not pay any dividends with respect to any shares of its capital stock other than (i) quarterly cash dividends not to exceed the amounts set forth on ITC’s confidential disclosure letter, declared and paid in the ordinary course and with record dates and payment dates consistent with past practice, (ii) dividends payable by a wholly owned subsidiary of ITC to ITC or another wholly owned subsidiary and (iii) if elected, a one-time special dividend to ITC’s pre-merger shareholders in accordance with the merger agreement.

For more information on ITC’s dividend policy, see “The Transactions—ITC’s Dividend Policy and $700 Million Recapitalization.”

SELECTED FINANCIAL STATEMENT DATA

Selected Historical Combined Financial Data of Entergy’s Transmission Business

Entergy’s Transmission Business’ selected combined statement of income data for the three years ended December 31, 2011, 2010 and 2009 and combined balance sheet data as of December 31, 2011 and 2010 have been derived from Entergy’s Transmission Business’ audited combined financial statements, included elsewhere in this proxy statement/prospectus. Entergy’s Transmission Business’ selected combined balance sheet data as of December 31, 2009, 2008, and 2007 and its selected statements of income data presented below for the years ended December 31, 2008 and 2007 have been derived from Entergy’s Transmission Business’ historical accounting records, which are unaudited and are not included in this proxy statement/prospectus. Entergy’s Transmission Business’ selected combined statement of income data for the nine months ended September 30, 2012 and 2011 and selected combined balance sheet data as of September 30, 2012 have been derived from Entergy’s Transmission Business’ unaudited condensed combined financial statements, included elsewhere in this proxy statement/prospectus. The selected historical combined financial data below is not necessarily indicative of the results that may be expected for any future period. This information should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations for Entergy’s Transmission Business” and the financial statements of Entergy’s Transmission Business and the notes thereto included elsewhere in this proxy statement/prospectus.

The financial information of Entergy’s Transmission Business included in this proxy statement/prospectus has been derived from the financial statements and accounting records of Entergy and reflects assumptions and allocations made by Entergy. The financial position, results of operations and cash flows of Entergy’s Transmission Business presented may be different from those that would have resulted had Entergy’s Transmission Business been operated as a stand-alone company. Additionally, the financial position, results of operations and cash flows of Entergy’s Transmission Business presented reflect its existing state and local jurisdictional rate regulation as a component of the Utility Operating Companies, as compared to the FERC rate regulation expected for Entergy’s Transmission Business under ITC’s ownership. As a result, the historical financial information of Entergy’s Transmission Business is not a reliable indicator of future results. See “Risk Factors.”