AmericasActive:18013672.13 EXELON CORPORATION $1,000,000,000 5.150% Notes Due 2028 $850,000,000 5.300% Notes Due 2033 $650,000,000 5.600% Notes Due 2053 UNDERWRITING AGREEMENT February 16, 2023 To the Representatives of the several Underwriters listed...

AmericasActive:18013672.13 EXELON CORPORATION $1,000,000,000 5.150% Notes Due 2028 $850,000,000 5.300% Notes Due 2033 $650,000,000 5.600% Notes Due 2053 UNDERWRITING AGREEMENT February 16, 2023 To the Representatives of the several Underwriters listed in Schedule 1 hereto Ladies and Gentlemen: Exelon Corporation, a Pennsylvania corporation (the “Company”), proposes to sell to the several Underwriters listed in Schedule 1 hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), $1,000,000,000 principal amount of its 5.150% Notes due 2028 (the “2028 Notes”), $850,000,000 principal amount of its 5.300% Notes due 2033 (the “2033 Notes”) and $650,000,000 principal amount of its 5.600% Notes due 2053 (the “2053 Notes” and, collectively with the 2028 Notes and the 2033 Notes, the “Securities”). The Securities are to be issued under a base indenture, to be dated as of June 11, 2015 (the “Base Indenture”) between the Company and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”), as amended and supplemented by the supplemental indenture, to be dated as of February 1, 2023 (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”). Any reference herein to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 which were filed under the Exchange Act on or before the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be; and any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the filing of any document under the Exchange Act after the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be, deemed to be incorporated therein by reference. Certain terms used herein are defined in Section 20 hereof. The Company hereby confirms its agreement with the several Underwriters concerning the purchase and sale of the Securities, as follows: 1. Registration Statement. As of the date of this Agreement, the Applicable Time of Sale and the Closing Date (as defined herein), the Company represents and warrants to, and agrees with, each Underwriter as set forth below in this Section 1. (a) The Company meets the requirements for use of Form S-3 under the Act and has prepared and filed with the Commission an automatic shelf registration statement, as defined in Rule 405 on Form S-3 (Registration No. 333-266487), including a related base prospectus, for registration under the Act of the offering and sale of the Securities. Such Registration Statement, including any amendments thereto filed prior to the Execution Time, became effective upon filing under Rule 462(e). The Company may have filed one or more amendments thereto, including a Preliminary Prospectus, each of which has previously been furnished to you. The Company will next file with the Commission a final term sheet as contemplated by Section 4(b) hereof and a final prospectus supplement relating to the Securities in accordance with Rules 415 and 424(b). As filed, such final prospectus supplement shall contain all 430B Information, together with all other such required information, and, except to the extent the Representatives shall agree in writing to a modification, shall be in all substantive respects in the form furnished to you prior to the Execution Time or, to the extent not completed at the Execution Time, shall contain only such specific additional information and other changes (beyond that contained in the Base Prospectus, any Preliminary Prospectus EXECUTION VERSION

2 AmericasActive:18013672.13 and Schedule 1 hereto) as the Company has advised you, prior to the Execution Time, will be included or made therein. The Registration Statement, at the Execution Time, meets the requirements set forth in Rule 415(a)(1)(x). (b) (i) At the time of filing the Registration Statement, (ii) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Sections 13 or 15(d) of the Exchange Act or form of prospectus) and (iii) at the time the Company or any person acting on its behalf (within the meaning, for this clause only, of Rule 163(c)) made any offer relating to the Securities in reliance on the exemption in Rule 163, the Company was or is (as the case may be) a “well-known seasoned issuer” as defined in Rule 405. The Company agrees to pay the fees required by the Commission relating to the Securities within the time required by Rule 456(b)(1) without regard to the proviso therein and otherwise in accordance with Rules 456(b) and 457(r). (c) On the Effective Date, the Registration Statement did, and when the Final Prospectus is first filed in accordance with Rule 424(b) and on the Closing Date (as defined herein), the Final Prospectus (and any supplement thereto) will, comply in all material respects with the applicable requirements of the Act, the Exchange Act, the Trust Indenture Act and the respective rules thereunder; on the Effective Date and at the Execution Time and as of the “new effective date” with respect to the Securities pursuant to, and within the meaning of, Rule 430B(f)(2), the Registration Statement did not and will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading; on the Effective Date and on the Closing Date the Indenture did or will comply in all material respects with the applicable requirements of the Trust Indenture Act and the rules thereunder; and, on the date of any filing pursuant to Rule 424(b) and on the Closing Date, the Final Prospectus (together with any supplement thereto) will not include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the Company makes no representations or warranties as to (i) that part of the Registration Statement which shall constitute the Statement of Eligibility and Qualification (Form T-1) under the Trust Indenture Act of the Trustee or (ii) the information contained in or omitted from the Registration Statement or the Final Prospectus (or any supplement thereto) in reliance upon and in conformity with information furnished in writing to the Company by or on behalf of any Underwriter through the Representatives specifically for inclusion in the Registration Statement or the Final Prospectus (or any supplement thereto), it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 6(b) hereof. (d) The Disclosure Package did not, as of the time and date designated as the “Applicable Time of Sale” include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 6(b) hereof. (e) The Company has not made and will not make (other than the final term sheet prepared and filed pursuant to Section 4(b) hereof) any offer relating to the Securities that would constitute a “free writing prospectus” (as defined in Rule 405 under the Act), without the prior written consent of the Representatives; the Company will comply with the requirements of Rule 433 under the Act with respect to any such free writing prospectus; any such free writing prospectus (including the final term sheet prepared and filed pursuant to Section 4(b) hereof) will not, as of its issue date and through the completion of the public offer and sale of the Securities, include any information that is inconsistent with the information contained in the Registration Statement, the Preliminary Prospectus and the Final Prospectus, and any such free writing prospectus, when taken together with the information contained in the Registration Statement, the Disclosure Package and the Final Prospectus, did not, when issued or filed pursuant to Rule 433 under the Act, include an untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. For the purpose of clarity, nothing in this Section 1(e) shall restrict the Company from making any filings required in order to comply with its reporting obligations under the Exchange Act or the rules and regulations of the Commission promulgated thereunder.

3 AmericasActive:18013672.13 (f) At the earliest time after the filing of the Registration Statement that the Company or another offering participant (x) made a bona fide offer of the Securities (within the meaning of Rule 164(h)(2)) and (y) as of the Execution Time (with such date being used as the determination date for purposes of this clause (y)), the Company was not and is not an Ineligible Issuer (as defined in Rule 405), without taking account of any determination by the Commission pursuant to Rule 405 that it is not necessary that the Company be considered an Ineligible Issuer. 2. Purchase of the Securities by the Underwriters. (a) On the basis of the representations and warranties herein contained, but subject to the terms and conditions set forth herein, the Company agrees to sell to each of the Underwriters, and each Underwriter agrees, severally and not jointly, to purchase from the Company, at the purchase prices set forth on Schedule 2 hereto, the principal amount of the Securities set forth opposite such Underwriter’s name in Schedule 1 hereto. The Underwriters agree to make a public offering of their respective Securities specified in Schedule 1 hereto at the prices to public specified in Schedule 2 hereto. It is understood that after such initial offering, the several Underwriters reserve the right to vary the offering price and further reserve the right to withdraw, cancel or modify any subsequent offering without notice. The Company shall not be obligated to deliver any of the Securities, except upon payment for all of the Securities to be purchased on the Closing Date. (b) Delivery of the Securities and payment therefor by the Representatives for the accounts of the several Underwriters shall be made at the offices of Xxxxxxx Xxxxx LLP at 10:00 A.M., New York City time, on February 21, 2023, or at such other time or place on the same or such other date, not later than the fifth Business Day thereafter, as the Representatives and the Company may agree upon in writing. Such time and date for delivery of the Securities is herein called the “Closing Date.” On the Closing Date, the Company, through the facilities of The Depository Trust Company (“DTC”), shall deliver or cause to be delivered a securities entitlement with respect to the Securities to the Representatives for the accounts of each Underwriter against payment of the purchase price by wire transfer of same day funds to a bank account designated by the Company. Time shall be of the essence, and delivery at the time and place specified pursuant to this Agreement is a further condition of the obligation of each Underwriter hereunder. Upon delivery, the Securities shall be registered in the name of Cede & Co., as nominee for DTC. 3. Representations and Warranties of the Company. The Company represents and warrants to and agrees with each Underwriter that: (a) Agreement. This Agreement has been duly authorized, executed and delivered by the Company. (b) The Securities. The Securities have been duly authorized and, when executed and authenticated by the Trustee in accordance with the provisions of the Indenture and delivered to and paid for in accordance with the provisions of the Indenture, will have been duly executed and delivered by the Company and will constitute the legal, valid and binding obligations of the Company enforceable against the Company in accordance with their terms and entitled to the benefits of the Indenture, except as enforceability may be limited by applicable bankruptcy, insolvency or similar laws affecting creditors’ rights generally or by equitable principles relating to enforceability (collectively, the “Enforceability Exceptions”). The Securities will conform in all material respects to the description thereof contained in the Disclosure Package and the Final Prospectus. (c) Indenture. The Indenture has been duly authorized and, when executed and delivered by the Company, will constitute a legal, valid, binding instrument enforceable against the Company in accordance with its terms, subject to the Enforceability Exceptions. The Indenture will conform in all material respects to the descriptions thereof contained in the Disclosure Package and the Final Prospectus. (d) Investment Company Act. The Company is not, and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Disclosure Package and the Final Prospectus, will not be required to register as an “investment company” under the Investment Company Act. (e) No Market Manipulation. The Company has not taken, directly or indirectly, any action designed to cause or which has constituted or which might reasonably be expected to cause or result, under the

6 AmericasActive:18013672.13 Bribery Act 2010, or other similar anti-bribery or anti-corruption law (collectively, “Anti-Corruption Laws”); or (iv) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including, without limitation, any rebate, payoff, influence payment, kickback or other unlawful or improper payment or benefit. The Company and its subsidiaries have conducted, and will continue to conduct, their businesses in compliance with Anti-Corruption Laws and have instituted, maintained and enforced, and will continue to institute, maintain and enforce, policies and procedures designed to promote compliance with all applicable Anti-Corruption Laws. (u) Anti-Money Laundering Laws. The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended (including, without limitation, by Title III of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act)), the money laundering statutes of all jurisdictions where the Company or any of its subsidiaries conducts business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Anti- Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or its subsidiaries with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of the Company, threatened. The Company and its subsidiaries have instituted and maintained and will continue to maintain policies and procedures reasonably designed to promote and achieve compliance with the Anti-Money Laundering Laws. (v) Cybersecurity. Except as disclosed in the Disclosure Package and the Final Prospectus, there has been no material security breach or incident involving unauthorized access or disclosure of any of the Company’s or its subsidiaries’ information technology and computer systems, networks, hardware, software, data (including the data of their respective customers, employees, suppliers, vendors and any third party data maintained by or on behalf of them), equipment or technology (collectively, “IT Systems and Data”) that could reasonably be expected to give rise to a data breach notification obligation to affected individuals under applicable data breach notification law or that could reasonably be expected to require disclosure or a notification thereof to the Commission or other applicable regulatory authority (a “Security Breach”) and (y) the Company and its subsidiaries have not been notified of, and have no knowledge of any event or condition that would reasonably be expected to result in, any Security Breach to their IT Systems and Data; (ii) the Company and its subsidiaries are presently in compliance with all applicable laws or statutes and all judgments, orders, rules and regulations of any court or arbitrator or governmental or regulatory authority, internal policies and contractual obligations relating to the privacy and security of IT Systems and Data and to the protection of such IT Systems and Data from unauthorized use, access, misappropriation or modification, except as would not, in the case of this clause (ii), individually or in the aggregate, have a Material Adverse Effect; and (iii) the Company and its subsidiaries have implemented backup and disaster recovery technology reasonably consistent with industry standards and practices. (w) OFAC. Neither the Company, any of its subsidiaries, or any director, officer, or employee thereof, nor to the knowledge of the Company, any agent affiliate, or other person associated with or acting on behalf of the Company or any of its subsidiaries is currently subject to any sanctions administered or enforced by the United States Government (including the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”) and the U.S. Department of State), the United Nations Security Council, the European Union, His Majesty’s Treasury, or any other relevant sanctions authority (collectively, “Sanctions”); nor is the Company or any of its subsidiaries located, organized or resident in a country or territory that is the subject or the target of Sanctions, including, without limitation, Cuba, Iran, North Korea, Syria, Crimea, the so-called Donetsk People’s Republic, the so-called Luhansk People’s Republic, the non-Ukrainian government controlled areas of the Zaporizhzhia and Kherson regions of Ukraine, or any other Covered Region of Ukraine identified pursuant to Executive Order 14065 (each, a “Sanctioned Country”). The Company and its subsidiaries have instituted and maintained and will continue to maintain policies and procedures reasonably designed to promote and achieve compliance with Sanctions. For the past five (5) years, to the knowledge of the Company, neither the Company nor any of its subsidiaries has engaged in or is now engaged in any dealings or transactions with any Person, or in any country or territory, that at the time of this dealing or transaction is or was, or whose government is or was, the subject of Sanctions, to the extent such dealings or transactions would be prohibited by applicable Sanctions.

12 AmericasActive:18013672.13 each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, officer, employee and agent of an Underwriter shall have the same rights to contribution as such Underwriter and each person who controls the Company within the meaning of either the Act or the Exchange Act, each officer of the Company and each director of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (d). 7. [Reserved]. 8. Termination. This Agreement may be terminated in the absolute discretion of the Representatives by notice to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date (A) at any time prior to such time (i) trading in the common stock of the Company shall have been suspended by the Commission, the New York Stock Exchange (the “NYSE”) or the Nasdaq Global Select Market (“Nasdaq”) or trading in securities generally on the NYSE or Nasdaq shall have been suspended or limited or minimum prices shall have been established on such exchanges, (ii) a banking moratorium shall have been declared either by federal or New York State authorities, (iii) a major disruption of settlements of securities or clearance services in the United States shall have occurred, (iv) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war, or other calamity or crisis, (v) downgrading shall have occurred in the rating accorded the Company’s debt securities by any “nationally recognized statistical rating organization,” as that term is defined by the Commission for purposes of Section 3(a)(62) of the Exchange Act or (vi) such organization shall have publicly announced that it has under surveillance or review, with possible negative implications, its rating of any of the Company’s debt securities and (B) the effect of the event as set forth in the foregoing clauses (iii) and (iv), as the case may be, on the financial markets is such as to make it, in the sole judgment of the Representatives, impractical or inadvisable to proceed with the offering or delivery of the Securities as contemplated by the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto). 9. Defaulting Underwriter. (a) If any one or more Underwriters shall fail to purchase and pay for any of the Securities agreed to be purchased by such Underwriter or Underwriters hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Underwriters shall be obligated severally to take up and pay for (in the respective proportions which the principal amount of the Securities set forth opposite their names in Schedule 1 hereto bears to the aggregate principal amount of the Securities set forth opposite the names of all the remaining Underwriters) the Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate principal amount of the Securities which the defaulting Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of the aggregate principal amount of the Securities set forth in Schedule 1 hereto, the remaining Underwriters shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Securities the defaulting Underwriter failed to purchase. (b) If the non-defaulting Underwriters are not obligated to and do not purchase all the Securities the defaulting Underwriter failed to purchase, the Company shall be entitled to a period of 36 hours within which to procure other persons reasonably satisfactory to the non-defaulting Underwriters to purchase such Shares and if arrangements for the purchase of such Shares by other persons selected by the Company and reasonably satisfactory to the Representative are not made within 36 hours after such default, this Agreement will terminate without liability to any non-defaulting Underwriter or the Company unless the Company elects to reduce the principal amount of the Securities to be offered by the amount of the Securities that the defaulting Underwriter failed to purchase, in which event the non-defaulting Underwriters will have the right to purchase all, but shall not be under any obligation to purchase any, of such reduced principal amount of the Securities. In the event the non-defaulting Underwriters decline to purchase all of such reduced principal amount of the Securities, this Agreement will terminate without any liability on the part of the non-defaulting Underwriters or the Company. (c) In the event of a default by any Underwriter as set forth in this Section 9, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Representatives shall determine in order that the required changes in the Registration Statement and the Final Prospectus or in any other documents or arrangements may be effected. Nothing contained in this Agreement shall relieve any defaulting Underwriter of its liability, if any, to the Company and any non-defaulting Underwriter for damages occasioned by its default hereunder.

14 AmericasActive:18013672.13 “Covered Entity” means any of the following: (i) a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b); (ii) a “covered bank” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or (iii) a “covered FSI” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b). “Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable. “U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Xxxx-Xxxxx Xxxx Street Reform and Consumer Protection Act and the regulations promulgated thereunder. 13. Notices. All communications hereunder will be in writing and effective only on receipt, and, if sent to (i) the Representatives, will be mailed, delivered or telefaxed to Barclays Capital Inc., 000 Xxxxxxx Xxxxxx, Xxx Xxxx, Xxx Xxxx 00000, Attention: Syndicate Registration (fax: 000-000-0000), Citigroup Global Markets Inc., 000 Xxxxxxxxx Xxxxxx, Xxx Xxxx, Xxx Xxxx 00000, Attention: General Counsel (fax: 000-000-0000), Xxxxxxx Xxxxx & Co. LLC, 000 Xxxx Xxxxxx, Xxx Xxxx, Xxx Xxxx 00000, Attention: Registration Department (fax: 000-000-0000), X.X. Xxxxxx Securities LLC, 000 Xxxxxxx Xxxxxx, Xxx Xxxx, Xxx Xxxx 00000, Attention: Investment Grade Syndicate Desk (fax: 000-000-0000) and Xxxxxx Xxxxxxx & Co. LLC, 0000 Xxxxxxxx, Xxx Xxxx, Xxx Xxxx 00000, Attention: Investment Banking Division (fax no.: (000) 000-0000) and (ii) the Company, will be mailed, delivered or telefaxed to Exelon Corporation, 00 Xxxxx Xxxxxxxx Xxxxxx, 00xx Xxxxx, P.O. Box 805398, Chicago, Illinois 60680- 5398, Attention: Vice President and Treasurer (fax no.: (000) 000-0000); E-mail: xxxx.xxxxx@xxxxxxxxxx.xxx and confirmed to the General Counsel (fax no.: (000) 000-0000). 14. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers, directors, employees, agents and controlling persons referred to in Section 6 hereof, and no other person will have any right or obligation hereunder. 15. Research Analyst Independence. The Company and the Underwriters acknowledge that the Underwriters’ research analysts and research departments are required to be independent from their respective investment banking divisions and are subject to certain regulations and internal policies, and that such Underwriters’ research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering of the Securities that differ from the views of their respective investment banking divisions. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the Underwriters with respect to any conflict of interest that may arise from the fact that the views expressed by their independent research analysts and research departments may be different from or inconsistent with the views or advice communicated to the Company by such Underwriters’ investment banking divisions. The Company acknowledges that each of the Underwriters is a full service securities firm and as such from time to time, subject to applicable securities laws, may effect transactions for its own account or the account of its customers and hold long or short positions in debt securities of the Company. 16. Patriot Act Acknowledgment. The parties hereto acknowledge that in accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriters to properly identify their respective clients. 17. No Fiduciary Duty. The Company hereby acknowledges that (a) the purchase and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the Underwriters and any affiliate thereof through which it may be acting, on the other, (b) the Underwriters are acting as principals and not as agents or fiduciaries of the Company and (c) the Company’s engagement of the Underwriters in connection with the offering and the process leading up to the offering is as independent contractors

15 AmericasActive:18013672.13 and not in any other capacity. Furthermore, the Company agrees that it is solely responsible for making its own judgments in connection with the offering (irrespective of whether any of the Underwriters has advised or is currently advising the Company on related or other matters). The Company agrees that it will not claim that the Underwriters have rendered advisory services of any nature or respect, or owe an agency, fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto. 18. Applicable Law. This Agreement will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York. 19. Waiver of Jury Trial. The Company and the Underwriters hereby irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. 20. Counterparts. This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement. 21. Electronic Signature. Counterparts may be delivered via facsimile, electronic mail (including any electronic signature covered by the U.S. federal ESIGN Act of 2000, Uniform Electronic Transactions Act, the Electronic Signatures and Records Act or other applicable law) xxx.xxxxxxxx.xxx or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes. 22. Headings. The section headings used herein are for convenience only and shall not affect the construction hereof. 23. Certain Defined Terms. The terms which follow, when used in this Agreement, shall have the meanings indicated. “Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder. “Agreement” shall mean this Underwriting Agreement including all schedules attached hereto and made a part hereof. “Applicable Time of Sale” shall mean 4:40 P.M. Eastern Time on February 16, 2023. “Base Prospectus” shall mean the base prospectus filed by the Company referred to in paragraph 1(a) above contained in the Registration Statement on the Effective Date. “Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in New York City. “Commission” shall mean the Securities and Exchange Commission. “Disclosure Package” shall mean (i) the Preliminary Prospectus, including the Base Prospectus, as amended and supplemented to the Applicable Time of Sale, (ii) the final term sheet prepared and filed pursuant to Section 4(b) hereof, (iii) any Issuer Free Writing Prospectus and (iv) any other Free Writing Prospectus that the parties hereto shall hereafter expressly agree in writing to treat as part of the Disclosure Package. Notwithstanding any provision hereof to the contrary, each document included in the Disclosure Package shall be deemed to include all documents incorporated therein by reference, whether any such incorporated document is filed before or after the document into which it is incorporated, so long as the incorporated document is filed before the Applicable Time of Sale. “Effective Date” shall mean each date and time that the Registration Statement, any post-effective amendment or amendments thereto became or becomes effective.

Signature Page to Undewriting Agreement Very truly yours, EXELON CORPORATION By: Name: Xxxx Xxxxx Title: Vice President and Treasurer


[SIGNATURE PAGE TO UNDERWRITING AGREEMENT (CITIGROUP GLOBAL MARKETS INC.)] Accepted as of the date first set forth above: Acting on behalf of itself and the several Underwriters listed in Schedule 1 hereto. BARCLAYS CAPITAL INC. By: Name: Title: CITIGROUP GLOBAL MARKETS INC. By: Name: Title: XXXXXXX XXXXX & CO. LLC By: Name: Title: X.X. XXXXXX SECURITIES LLC By: Name: Title: XXXXXX XXXXXXX & CO. LLC By: Name: Title: Xxxxx X. Xxxxxxxxx Managing Director

[SIGNATURE PAGE TO UNDERWRITING AGREEMENT (XXXXXXX XXXXX & CO. LLC)] Accepted as of the date first set forth above: Acting on behalf of itself and the several Underwriters listed in Schedule 1 hereto. BARCLAYS CAPITAL INC. By: Name: Title: CITIGROUP GLOBAL MARKETS INC. By: Name: Title: XXXXXXX XXXXX & CO. LLC By: Name: Title: X.X. XXXXXX SECURITIES LLC By: Name: Title: XXXXXX XXXXXXX & CO. LLC By: Name: Title: Xxxxxx Xxxxxx Vice President

[SIGNATURE PAGE TO UNDERWRITING AGREEMENT (X.X. XXXXXX SECURITIES LLC)] Accepted as of the date first set forth above: Acting on behalf of itself and the several Underwriters listed in Schedule 1 hereto. BARCLAYS CAPITAL INC. By: Name: Title: CITIGROUP GLOBAL MARKETS INC. By: Name: Title: XXXXXXX XXXXX & CO. LLC By: Name: Title: X.X. XXXXXX SECURITIES LLC By: Name: Title: XXXXXX XXXXXXX & CO. LLC By: Name: Title: Xxxxxx Xxxxxxxxx Executive Director


Schedule 1-1 AmericasActive:18013672.13 Schedule 1 Underwriter Principal Amount of 2028 Notes to be Purchased Principal Amount of 2033 Notes to be Purchased Principal Amount of 2053 Notes to be Purchased Barclays Capital Inc. ............................................. $138,000,000 $117,300,000 $89,700,000 Citigroup Global Markets Inc. .............................. 138,000,000 117,300,000 89,700,000 Xxxxxxx Xxxxx & Co. LLC .................................. 138,000,000 117,300,000 89,700,000 X.X. Xxxxxx Securities LLC .................................. 138,000,000 117,300,000 89,700,000 Xxxxxx Xxxxxxx & Co. LLC ................................. 138,000,000 117,300,000 89,700,000 MUFG Securities Americas Inc. ........................... 60,000,000 51,000,000 39,000,000 PNC Capital Markets LLC ................................... 60,000,000 51,000,000 39,000,000 SMBC Nikko Securities America, Inc. ................. 60,000,000 51,000,000 39,000,000 Xxxxx Fargo Securities, LLC ................................ 60,000,000 51,000,000 39,000,000 Huntington Securities, Inc. ................................... 16,700,000 14,200,000 10,800,000 Loop Capital Markets LLC ................................... 16,700,000 14,100,000 10,900,000 Xxxxxxx Xxxxxxxx Xxxxx & Co., LLC .................... 16,600,000 14,200,000 10,800,000 Apto Partners, LLC……………………………… 4,000,000 3,400,000 2,600,000 Xxxxxxxx Van, LLC……………………………… 4,000,000 3,400,000 2,600,000 X.X. Xxxx & Associates, Inc……………………. 4,000,000 3,400,000 2,600,000 Multi-Bank Securities, Inc……………………… 4,000,000 3,400,000 2,600,000 Telsey Advisory Group LLC…………………… 4,000,000 3,400,000 2,600,000 Total……………………………………………. $1,000,000,000 $850,000,000 $650,000,000

Schedule 2-1 AmericasActive:18013672.13 Schedule 2 Underwriting Agreement, dated February 16, 2023 Registration Statement No. 333-266487 Representatives: Barclays Capital Inc. Citigroup Global Markets Inc. Xxxxxxx Xxxxx & Co. LLC X.X. Xxxxxx Securities LLC Xxxxxx Xxxxxxx & Co. LLC A. Title, Purchase Price and Description of 2028 Notes: Title: 5.150% Notes Due 2028 Principal amount: $1,000,000,000 Price to public: 99.832% ($998,320,000) Underwriting discount: 0.600% ($6,000,000) Purchase price: 99.232% ($992,320,000), plus accrued interest, if any Sinking fund provisions: None Redemption provisions: As set forth in the Final Prospectus Other provisions: As set forth in the Final Prospectus B. Title, Purchase Price and Description of 2033 Notes: Title: 5.300% Notes Due 2033 Principal amount: $850,000,000 Price to public: 99.895% ($849,107,500) Underwriting discount: 0.650% ($5,525,000) Purchase price: 99.245% ($843,582,500), plus accrued interest, if any Sinking fund provisions: None Redemption provisions: As set forth in the Final Prospectus Other provisions: As set forth in the Final Prospectus C. Title, Purchase Price and Description of 2053 Notes: Title: 5.600% Notes Due 2053 Principal amount: $650,000,000

Schedule 2-2 AmericasActive:18013672.13 Price to public: 99.691% ($647,991,500) Underwriting discount: 0.875% ($5,687,500) Purchase price: 98.816% ($642,304,000), plus accrued interest, if any Sinking fund provisions: None Redemption provisions: As set forth in the Final Prospectus Other provisions: As set forth in the Final Prospectus D. Other Provisions Relating to the Securities Closing Date, Time and Location: February 21, 2023 at approximately 10:00 A.M. ET Xxxxxxx Xxxxx LLP 0000 Xxxxxx Xxxxxx, 00xx Xxxxx Xxxxxxxxxxxx, Xxxxxxxxxxxx 00000 Type of Offering: Non-delayed Applicable Time of Sale of the Securities pursuant to Section 1(d) of the Underwriting Agreement: 4:40 P.M. ET, February 16, 2023

Schedule 3-1 AmericasActive:18013672.13 Schedule 3 FORM OF COMPANY COUNSEL OPINION 1. The Company is a corporation duly incorporated and presently subsisting under the laws of the Commonwealth of Pennsylvania and duly authorized to exercise all the powers recited in its charter or certificate of incorporation, and to transact business in the Commonwealth of Pennsylvania. 2. The Company has all requisite corporate power and authority to own or lease, as the case may be, its properties and conduct its business as described in the Disclosure Package and the Final Prospectus. 3. The Agreement has been duly authorized, executed and delivered by the Company. 4. The Indenture has been duly authorized, executed and delivered by the Company. The Indenture has been duly qualified under the Trust Indenture Act. 5. The Securities have been duly authorized, executed and delivered by the Company and, when authenticated and delivered by the Trustee against payment therefor, will constitute legal, valid and binding obligations of the Company. 6. The execution and delivery of the Agreement by the Company and the performance of the Company’s obligations thereunder, and the issuance and sale of the Securities to you, do not and will not contravene, result in a breach or violation of, or imposition of any lien, charge or encumbrance upon any property or asset of the Company pursuant to (i) the Articles of Incorporation or By-Laws of the Company, (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company is a party or bound or to which its property is subject that is listed in the Exhibit Index to the Company’s Form 10-K for the fiscal year ended December 31, 2015 or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of its properties. 7. No consent, approval, authorization, or order of, or qualification with, any state commission or regulatory authority or of any other governmental body or agency of the Commonwealth of Pennsylvania is required to be obtained by the Company with respect to the issuance and sale of the Securities and the performance by the Company of its obligations under the Transaction Agreements. 8. Our firm is not representing the Company in any pending litigation in which it is a named defendant, or in any litigation that is overtly threatened in writing against it by a potential claimant, that challenges the validity or enforceability of, or seeks to enjoin the performance of, the transactions contemplated by the Transaction Agreements, and to our knowledge, there are no pending legal proceedings in the Commonwealth of Pennsylvania to which the Company or any subsidiary is a party which is required to be set forth pursuant to Item 103 of Regulation S-K promulgated under the Securities Act in the documents incorporated by reference in the Disclosure Package and the Final Prospectus other than those referred to in such documents. 9. The Registration Statement has become effective under the Act; any required filing of the Base Prospectus, the Preliminary Prospectus and the Final Prospectus, and any supplements thereto, pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); to our knowledge, no stop order suspending the effectiveness of the Registration Statement or any notice by the Commission objecting to its use has been issued, no proceedings for that purpose have been instituted or threatened, and the Registration Statement (other than the financial statements and other financial information contained therein, as to which we express no opinion) as of the date the Registration Statement originally became effective under the Act, and together with the Preliminary Prospectus and the Final Prospectus, as of each “new effective date” within respect to the Securities pursuant to and within the meaning of Rule 430B(f0(2) under the Act, complied, and the Preliminary Prospectus and the Final Prospectus (other than the financial statements and other financial information contained therein, as to which we express no opinion), as of their respective dates, complied, and the Final Prospectus (other than the financial statements and other financial

Schedule 3-2 AmericasActive:18013672.13 information contained therein, as to which we express no opinion), as of the date hereof, complies, in each case as to form in all material respects with the applicable requirements of the Act, the Securities Exchange Act of 1934, as amended, and the Trust Indenture Act and the respective rules thereunder. 10. The statements under the captions “Description of the Notes” and “Material United States Federal Income Tax Considerations” in the Time of Sale Information and the Prospectus, insofar as such statements constitute a summary of the legal matters or documents referred to therein, are accurate in all material respects. 11. The Company is not, and immediately after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described under “Use of Proceeds” in the Time of Sale Information and the Prospectus will not be, required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended. We have participated in the preparation of the Registration Statement, the Disclosure Package and the Final Prospectus, including participation in conferences with officers of the Company and the Company’s accountants. Although we have not undertaken to determine independently and assume no responsibility for the accuracy, completeness or fairness of the statements contained in the Registration Statement, the Disclosure Package or the Final Prospectus (except as provided in paragraph 9 above), based on that participation, we have no reason to believe that (1) the Registration Statement, at each time it became effective under the Act and (2) the Final Prospectus, as of its date and the date hereof in light of the circumstances under which they were made, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading (except, in the case of the Registration Statement, the Form T-1s and in the case of the Registration Statement and the Final Prospectus, the financial statements and other financial and statistical data included or incorporated by reference therein, as to which we express no opinion or belief). Additionally, we have no reason to believe that the Disclosure Package, as of the Applicable Time of Sale, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (other than the financial statements and other financial information contained therein, as to which we express no opinion or belief).

Annex I-1 AmericasActive:18013672.13 ANNEX I Exelon Corporation Pricing Term Sheet $1,000,000,000 5.150% Notes Due 2028 $850,000,000 5.300% Notes Due 2033 $650,000,000 5.600% Notes Due 2053 Issuer: Exelon Corporation Exelon Corporation Exelon Corporation Expected Ratings: -- -- -- Principal Amount: $1,000,000,000 $850,000,000 $650,000,000 Security Type: Notes Notes Notes Trade Date: February 16, 2023 February 16, 2023 February 16, 2023 Settlement Date: February 21, 2023 (T+2) February 21, 2023 (T+2) February 21, 2023 (T+2) Coupon: 5.150% 5.300% 5.600% Maturity Date: March 15, 2028 March 15, 2033 March 15, 2053 Interest Payment Dates: Semi-annually on March 15 and September 15, commencing September 15, 2023 Semi-annually on March 15 and September 15, commencing September 15, 2023 Semi-annually on March 15 and September 15, commencing September 15, 2023 Benchmark Treasury: 3.500% due January 31, 2028 3.500% due February 15, 2033 4.000% due November 15, 2052 Benchmark Treasury Price and Yield: 97-16 / 4.062% 97 00+ / 3.863% 101-12 / 3.921% Spread to Benchmark Treasury: 112.5 basis points 145 basis points 170 basis points Yield to Maturity: 5.187% 5.313% 5.621% Offering Price: 99.832% of Principal Amount 99.895% of Principal Amount 99.691% of Principal Amount Optional Redemption: At any time prior to February 15, 2028 (one month prior to the maturity date) (the “Par Call Date”), at a make whole price equal to the greater of (a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the bonds matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 20 basis points less (b) interest accrued to the date of redemption, and 100% of Any time prior to December 15, 2032 (three months prior to the maturity date) (the “Par Call Date”), at a make whole price equal to the greater of (a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the bonds matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 25 basis points less (b) interest accrued to the date of redemption, and 100% of Any time prior to September 15, 2052 (six months prior to the maturity date) (the “Par Call Date”), at a make whole price equal to the greater of (a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date (assuming the bonds matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 30 basis points less (b) interest accrued to the date of

Annex I-2 AmericasActive:18013672.13 Issuer: Exelon Corporation Exelon Corporation Exelon Corporation the principal amount of the bonds to be redeemed, plus, in each case, accrued and unpaid interest to the redemption date. the principal amount of the bonds to be redeemed, plus, in each case, accrued and unpaid interest to the redemption date. redemption, and 100% of the principal amount of the bonds to be redeemed, plus, in each case, accrued and unpaid interest to the redemption date. CUSIP/ISIN: 00000XXX0 / US30161NBJ90 00000XXX0 / US30161NBK63 00000XXX0 / US30161NBL47 Joint Bookrunners: Barclays Capital Inc. Citigroup Global Markets Inc. Xxxxxxx Xxxxx & Co. LLC Barclays Capital Inc. Citigroup Global Markets Inc. Xxxxxxx Xxxxx & Co. LLC Barclays Capital Inc. Citigroup Global Markets Inc. Xxxxxxx Xxxxx & Co. LLC X.X. Xxxxxx Securities LLC X.X. Xxxxxx Securities LLC X.X. Xxxxxx Securities LLC Xxxxxx Xxxxxxx & Co. LLC Xxxxxx Xxxxxxx & Co. LLC Xxxxxx Xxxxxxx & Co. LLC MUFG Securities Americas Inc. MUFG Securities Americas Inc. MUFG Securities Americas Inc. PNC Capital Markets LLC PNC Capital Markets LLC PNC Capital Markets LLC SMBC Nikko Securities America, Inc. Xxxxx Fargo Securities, LLC SMBC Nikko Securities America, Inc. Xxxxx Fargo Securities, LLC SMBC Nikko Securities America, Inc. Xxxxx Fargo Securities, LLC Senior Co-Managers: Co-Managers: Huntington Securities, Inc. Loop Capital Markets LLC Xxxxxxx Xxxxxxxx Xxxxx & Co., LLC Apto Partners, LLC Xxxxxxxx Van, LLC X.X. Xxxx & Associates Multi-Bank Securities, Inc. Telsey Advisory Group LLC Huntington Securities, Inc. Loop Capital Markets LLC Xxxxxxx Xxxxxxxx Xxxxx & Co., LLC Apto Partners, LLC Xxxxxxxx Van, LLC X.X. Xxxx & Associates Multi-Bank Securities, Inc. Telsey Advisory Group LLC Huntington Securities, Inc. Loop Capital Markets LLC Xxxxxxx Xxxxxxxx Xxxxx & Co., LLC Apto Partners, LLC Xxxxxxxx Van, LLC X.X. Xxxx & Associates Multi-Bank Securities, Inc. Telsey Advisory Group LLC The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting XXXXX on the SEC Web site at xxx.xxx.xxx. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling Barclays Capital Inc. toll-free at 0-000-000-0000, Citigroup Global Markets Inc. toll-free at 1-800-831-9146, Xxxxxxx Xxxxx & Co. LLC at 1-866-471-2526, X.X. Xxxxxx Securities LLC collect at 0-000-000-0000 and Xxxxxx Xxxxxxx & Co. LLC toll-free at 0-000-000-0000.