Core & Main, Inc.

What do I need to do to virtually attend the Annual Meeting?

You will need to go towww.virtualshareholdermeeting.com/CNM2025 and enter the control number located on your proxy card or follow the instructions that accompanied your proxy materials. We recommend that you log in at least 30 minutes before the meeting starts to ensure that you are logged in when the Annual Meeting begins. Only our shareholders and persons holding proxies from our shareholders may attend the Annual Meeting.

Although it will be a virtual-only meeting, the Company wants the Annual Meeting to provide shareholders with the same rights and opportunities to participate as in an in-person meeting, including the ability to ask questions of the Board and management. To support these efforts, the Company will:

•provide for Annual Meeting attendees to begin logging into the Annual Meeting at 8:30 a.m. Central Time on June 24, 2025, 30 minutes in advance of the meeting;

•permit participating shareholders to submit questions via live webcast during the Annual Meeting on the meeting website. Questions relevant to meeting matters will be answered during the meeting, subject to time constraints and discretion of the Chair of the Board. As stated in the rules of conduct, which are accessible on the meeting website, questions can be submitted in the field provided on the website for the Annual Meeting;

•post responses to questions relevant to meeting matters that are not answered during the Annual Meeting due to time constraints on the Company’s Investor Relations website, as soon as practicable after the Annual Meeting;

•provide the ability for participating shareholders of record to vote or revoke their prior vote by following the instructions available on the meeting website during the Annual Meeting. Shares for which a shareholder is the beneficial owner, but not the shareholder of record, also may be voted electronically during the Annual Meeting if the shareholder utilizes the control number located on their proxy card; and

•have technicians ready beginning 30 minutes prior to the Annual Meeting to assist participating shareholders with any technical difficulties they may have accessing the virtual meeting. If participating shareholders encounter any difficulties accessing the virtual meeting during check-in or the meeting, they may call the technical support number that will be posted on the virtual meeting platform login page.

The Company welcomes all of its shareholders to join and participate in the Annual Meeting. Whether you plan to attend, we urge you to vote and submit your proxy in advance of the Annual Meeting by one of the methods described in the proxy materials for the Annual Meeting.

What if the Company encounters technical difficulties during the Annual Meeting?

If we experience technical difficulties during the Annual Meeting (e.g., a temporary or prolonged power outage), our Chair will determine whether the meeting can be promptly reconvened (if the technical difficulty is temporary) or whether the meeting will need to be reconvened on a later day (if the technical difficulty is more prolonged). In any of these situations, we will promptly notify shareholders of the decision viawww.virtualshareholdermeeting.com/CNM2025 andhttps://ir.coreandmain.com. If you encounter technical difficulties accessing the Annual Meeting or asking questions during the Annual Meeting, a support line will be available on the login page of the virtual Annual Meeting website.