This section is intended as an overview of the Shareholder Investment Plan only. For detailed information please review the entire prospectus.

• Shareholder Investment Plan (SIP) Prospectus   (Dated: March 4, 2009)

About the Plan and How to Join

Constellation Energy offers a Shareholder Investment Plan (SIP) that allows you, as a registered shareholder, flexibility in managing your investment with the company.

If you would like to join the SIP, you must first read the prospectus (Dated: March 4, 2009). You may join the SIP at any time by enrolling online at www.amstock.com or by completing and returning an authorization form, which you may obtain online at www.amstock.com or by contacting the plan administrator at the following address or telephone number:

Phone and IVR service: 1-800-258-0499
Calls are answered Monday through Thursday from 8:00 a.m. to 7:00 p.m., and on Friday from 8:00 a.m. to 5:00 p.m., Eastern time. The IVR system is available 24 hours a day, 7 days a week.

Web site: www.amstock.com

SIP Transaction Fees (per transaction)

Reinvestment of dividends = 2% of dividend amount to a maximum of $2.50.
Optional cash investments = $2.50
Custody of certificated shares = $7.50 (if a sale is not also requested)
Sale of shares = $15.00
Termination of account = $15.00
Brokerage commission = $0.10 per share

Shareholder Investment Plan Features

Custody Of Shares

As a registered shareholder, you can deposit your Constellation Energy common stock certificates in the SIP at any time.

Reinvesting Dividends

As a registered shareholder, you can elect to reinvest

• all dividends, both on shares held in certificate form and shares deposited in the SIP, or
• only dividends on shares deposited in the SIP.

Purchasing Shares

As a registered shareholder, you can purchase additional shares of Constellation Energy common stock for your SIP account. Requesting Certificates for SIP Shares

Requesting Certificates for SIP Shares

You can request a stock certificate for some, or all, of the full shares held in your SIP account.

Selling Shares

You can sell shares held in your SIP account at any time.

To sell shares you hold in certificate form, you must first deposit the shares into your SIP account under the custody feature of the plan.

Transferring Plan Shares

You can request to transfer shares held in your SIP account to another existing account or a new account.

All stock transfer requests must be accompanied by an executed stock assignment form from each owner of the shares and each signature requires a Signature Guarantee Medallion*.

The Signature Guarantee Medallion verifies:

• The security is endorsed by the appropriate person(s), and
• The signer has the legal capacity to sign.

The plan administrator can provide you with a stock assignment form, or they are available from your bank or broker. We recommend you call your bank, credit union or broker to determine if they participate in a Signature Guarantee Medallion Program.

*The Signature Guarantee Medallion is not a notarization. It is a statement (stamp and signature) given by a financial institution such as a commercial bank, credit union, brokerage firm, etc., that are members of the Securities Transfer Association Medallion Program (STAMP), New York Stock Exchange Program or the Stock Exchange Medallion Program (SEMP, MSP).