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            <identifier scheme="http://www.sec.gov/CIK">0002013639</identifier>
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    <dei:EntityRegistrantName contextRef="P01_01_2024To12_31_2024" id="ixv-4334">FB Bancorp, Inc.</dei:EntityRegistrantName>
    <ecd:AwardTmgMnpiDiscTextBlock contextRef="P01_01_2024To12_31_2024" id="ixv-3125">&lt;div style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold"&gt;Policies and Practices Related to the Grant of Certain Equity Awards &lt;/div&gt;&lt;div style="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman"&gt;While the Company does not have formal policy or obligation that requires it to grant or award equity-based compensation on specific date, the Compensation Committee and the Board have a historical practice of not granting stock options to executive officers during closed quarterly trading windows as determined under the Company&#x2019;s insider trading policy. Consequently, the Company has not granted, and does not expect to grant, any stock options to any named executive officers within four business days preceding the filing with the Securities and Exchange Commission of any report on Forms &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;10-K,&lt;/div&gt; &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;10-Q&lt;/div&gt; or &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;8-K&lt;/div&gt; that discloses material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information. The Compensation Committee and the Board do not take material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information into account when determining the timing of equity awards and do not time the disclosure of material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information in order to impact the value of executive compensation. &lt;/div&gt;&lt;div style="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman"&gt;The Company did not grant any stock options to its executive officers, including the named executive officers, during the year ended December&#160;31, 2024. &lt;/div&gt;</ecd:AwardTmgMnpiDiscTextBlock>
    <ecd:AwardTmgMethodTextBlock contextRef="P01_01_2024To12_31_2024" id="ixv-3132">The Compensation Committee and the Board do not take material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information into account when determining the timing of equity awards and do not time the disclosure of material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information in order to impact the value of executive compensation.</ecd:AwardTmgMethodTextBlock>
    <ecd:AwardTmgHowMnpiCnsdrdTextBlock contextRef="P01_01_2024To12_31_2024" id="ixv-3133">The Compensation Committee and the Board do not take material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information into account when determining the timing of equity awards and do not time the disclosure of material &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;non-public&lt;/div&gt; information in order to impact the value of executive compensation.</ecd:AwardTmgHowMnpiCnsdrdTextBlock>
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