Mirant Spin-Off

Canadian taxpayers should consult their tax advisors as to the tax treatment of the Distribution under Canadian tax law. A recently effective change to the Canada Income Tax Act allows tax-free treatment of distributions to Canadian shareholders of U.S. companies under certain circumstances. Canadian authorities do consider our spin as tax free. Also, Canadian residents should consider whether the cash received for fractional shares is taxable, even if the distribution of the Mirant shares is not. Under U.S. tax law, a fractional share is treated as if it had been physically distributed to the shareholder and as if the shareholder had then sold it. Under U.S. tax law, a minor amount of gain or loss is recognized depending on the shareholder's basis in the fractional share.

On April 9, 2001, Distribution Statements were mailed to all Southern Company stockholders of record who owned Southern common stock as of March 21, 2001. This included stockholders owning shares in certificate form as well as shares held in book-entry form through the Southern Investment Plan. The Statement contained three primary sections:

Mirant Corporation and RRI Energy, Inc. completed their merger on 12/03/2010 to form GenOn Energy, Inc. (NYSE:GEN). In connection with the all-stock, tax-free merger, RRI Energy, Inc. changed its name to GenOn Energy, Inc. Each share of RRI stock will become a share of GenOn Energy common stock. Mirant stockholders will receive a fixed ratio of 2.835 shares of GenOn Energy common stock for each share of Mirant common stock. Please contact the Corporate Action Agent-Computershare directly regarding this transaction. The address is PO Box 43078, Providence, RI 02940-3078. Their web site is www.computershare.com

As Allen Franklin stated in the 2000 Annual Report, "Both Mirant and our traditional business were very successful and were continuing to meet or exceed all our financial targets. But we were not seeing the value of Mirant reflected in our stock price. The two parts of the business each offered something different to investors, and there was not a strong investor constituency for both under the same roof. As separate companies, investors have a clear choice between two "pure play" investments. The two businesses are worth more separated than they were together. With Mirant having grown big enough and strong enough to succeed independently, the time was right and it made good sense in the interests of our shareholders to separate. We have created two strong energy companies?Southern Company and Mirant?from one. In the process, we delivered the value of Mirant to our shareholders."

The "Record Date" for the Mirant distribution was 5:00 p.m., Eastern Time, on March 21, 2001. The record date is the date on which the number of Southern Company shares outstanding is established in order to calculate the distribution ratio. Southern Company stockholders who held shares outstanding as of the record date were eligible to receive the Mirant distribution.

The "Distribution Date" was 5:00 p.m., Eastern Time, on April 2, 2001. As of that time, Mirant shares were registered in accounts established on the ownership records of Mirant Corporation at its Transfer Agent, Mellon Investor Services, LLC.

Based on the number of shares of Southern Company common stock outstanding on the Record Date, stockholders received .397614 of a share of Mirant common stock for each share of Southern Company common stock owned on the Record Date. The actual rate was determined by dividing the number of Mirant shares to be issued - 272,000,000 - by the number of Southern Company common stock shares outstanding as of March 21, 2001 at 5:00 p.m., Eastern Time.

Southern Company common stock shares held in the Southern Investment Plan (SIP) was treated the same as any other shares during the spin-off. The Mirant shares distributed with respect to Southern Company shares held in the SIP were registered in your name and you became a record holder. The Mirant shares were issued in book-entry form, through the Direct Registration System, and, as more fully explained in the Information Statement, Mirant?s transfer agent, Mellon Investor Services, LLC, will hold your book-entry shares.

Your shares were be credited to you in book-entry form through the Direct Registration System on the books of Mirant Corporation. Following the Distribution Date of April 2, 2001, you were sent a Distribution Statement showing the number of shares you have been issued. Carefully review both sides of the Distribution Statement for important information about your Mirant shares, definitions and tax information.

No. The Distribution Agent was instructed to aggregate the fractional shares and sell them through an independent broker-dealer on the open market. A check for the fractional share proceeds was attached to the Distribution Statement.

The distribution was credited to the account of your broker or nominee who in turn credited the shares to your account. Any questions about shares held in street name should be directed to your broker or account representative.

Beginning on March 19, 2001, the NYSE established a "regular-way" and "when-issued" market for Southern Company common stock. Southern Company shares purchased in the regular way market included the right to receive the Mirant spin-off shares. Southern Company shares purchased in the "when-issued" market did not include the right to receive the Mirant spin-off shares. These two markets concluded with the close of the market on April 2, 2001.

No. Trading prices did not affect the number of shares you received or the distribution ratio.

The spin-off has no impact on the number of Southern Company shares that you own. Continue to safeguard the Southern Company certificates you have in your possession.

Southern Company has received a private letter ruling from the Internal Revenue Service stating that, based on representations made by Southern Company, the distribution of whole shares of Mirant common stock is tax-free for U.S. federal income tax purposes. Any cash payments received in lieu of fractional shares are taxable for U.S. federal income tax purposes. Consult the Information Statement for additional details. Stockholders are advised to consult their own tax advisors as to the particular tax consequences to them of the spin-off, including the federal, state, local and (if applicable) foreign tax consequences.

If you hold a mutual fund that owns Southern Company common stock, you need to check with the mutual fund advisor to see how the distribution was treated by the mutual fund.

The final distribution ratio calculated as of the Record Date, March 21, 2001, at 5:00 p.m., ET was 0.397614. This means that for each share of Southern Company common stock, owners of record were entitled to receive .397614 Mirant shares. For example, if a stockholder owned 100 shares of Southern, they are entitled to receive 39 shares of Mirant and a check for the sale of the .7614 fractional share.

Information on calculating basis can be found in IRS Publication 550. You are advised to consult your tax advisor.

Historical statement information is available by calling Stockholder Services at (800) 554-7626.

One such method is to allocate the tax basis in your shares of Southern Company stock immediately prior to the spin-off between your Southern Company stock and Mirant common stock, in proportion to the fair market value of each stock on April 2, 2001, the last trading day before the distribution. The closing price per share for Southern Company WI (without the distribution) on April 2, 2001, was $21.60. The closing price per share of Mirant WI on April 2, 2001, was $34.60. Using this methodology, and the 0.397614 distribution ratio, 61.09% of your basis would be allocated to Southern Company common stock, and the remaining 38.91% would be allocated to the shares of Mirant common stock received in the distribution (including any fractional share interest). You should consult your tax advisor regarding the application of this calculation to your particular circumstances.

Distribution Statements, including the fractional share check, IRS Form 1099B, Important U.S. Tax Information, and Information Statement to the IRS, were mailed on or about April 9, 2001.

The weighted average price per share paid for fractional shares of Mirant Corporation was $33.8517. The distribution agent aggregated all fractional shares into whole shares and had them sold in the open market by an independent broker-dealer.