Core & Main, Inc.

How do I vote?

The procedures for voting are as follows:

•Shareholder of Record. If you are a shareholder of record, you may vote online during the virtual Annual Meeting, vote by proxy using a proxy card, vote by proxy over the telephone or vote by proxy via the internet. Even if you do not plan to attend the Annual Meeting, we urge you to vote by proxy to ensure your vote is counted. You may still attend the Annual Meeting and vote, even if you have already voted by proxy. The vote you cast during the Annual Meeting will supersede any previous votes that you may have submitted.

•Vote by Internet. To vote by internet during the Annual Meeting, follow the instructions posted atwww.virtualshareholdermeeting.com/CNM2026. Shareholders of record may submit proxies prior to the Annual Meeting over the internet by visiting www.proxyvote.com and following the instructions on the Notice of Internet Availability or, if printed copies of the proxy materials were requested, the instructions on the printed proxy card. Most beneficial owners may vote by accessing the website specified on the voting instruction forms provided by their brokers, trustees, banks or other nominees. Please check your voting instruction form for internet voting availability.

•Vote by Telephone. Shareholders of record may submit proxies using any telephone from within the United States by following the instructions on the Notice of Internet Availability or, if printed copies of the proxy materials were requested, the instructions on the printed proxy card. Most beneficial owners may vote using any telephone by calling the number specified on the voting instruction forms provided by their brokers, trustees, banks or other nominees.

•Vote by Mail. Shareholders of record may submit proxies by mail by requesting printed proxy cards and completing, signing and dating the printed proxy cards and mailing them in the pre-addressed envelopes that will accompany the printed proxy materials. Beneficial owners may vote by completing, signing and dating the voting instruction forms provided and mailing them in the pre-addressed envelopes accompanying the voting instruction forms. If you are a shareholder of record and you return your signed proxy card but do not indicate your voting preferences, the persons named in the proxy card will vote the shares represented by that proxy as recommended by the Board. If you are a beneficial owner and you return your signed voting instruction form but do not indicate your voting preferences, please see “If I hold shares in street name through a broker, can the broker vote my shares for me?” regarding whether your broker, trustee, bank or other nominee may vote your uninstructed shares.

•Beneficial Owner. If you are a beneficial owner of shares registered in the name of your broker, trustee, bank or other nominee, you should have received a notice containing voting instructions from that organization rather than from us. Simply follow the voting instructions in that notice to ensure that your vote is counted. To vote during the Annual Meeting, you must obtain a valid proxy from your broker, trustee, bank or other nominee. Follow the instructions included with these proxy materials, or contact your broker, trustee, bank or other nominee to request a proxy form.

What if I change my mind after I return my proxy?

You may revoke your proxy and change your vote at any time before the polls close at the Annual Meeting. Shareholders of record may do this by:

•delivering written notice by mail, bearing a date later than the proxy, stating that the proxy is revoked, to 1830 Craig Park Court, St. Louis, Missouri 63146, Attn: Secretary;

•submitting a later-dated proxy relating to the same shares by mail, telephone or the internet prior to the vote at the Annual Meeting; or

•virtually attending and voting during the Annual Meeting.

Attendance at the Annual Meeting will not, by itself, revoke a proxy. If you hold shares through a bank, broker, trust or other nominee please refer to your voting instruction form, or other information forwarded by your bank, broker, trustee or other nominee to see how you can revoke your proxy and change your vote.

How many votes do you need to hold the Annual Meeting?

The presence electronically or represented by proxy at the Annual Meeting, of a majority of the voting power of the combined shares of Class A common stock and Class B common stock entitled to vote constitutes a quorum. A quorum must be present to conduct business at the Annual Meeting.

On what items am I voting?

You are being asked to vote on three items: (i) to elect three directors nominated by the Board and named in this proxy statement to serve as Class II directors for a term of three years expiring at the 2029 annual meeting of shareholders; (ii) to ratify the appointment of PwC as our independent registered public accounting firm for fiscal 2026; and (iii) to submit an advisory vote to approve NEO compensation for fiscal 2025.