    <SEC-DOCUMENT>0001628280-24-001787-index.html : 20240119
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    <ACCEPTANCE-DATETIME>20240119171425
    ACCESSION NUMBER:		0001628280-24-001787
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		19
    CONFORMED PERIOD OF REPORT:	20240115
    ITEM INFORMATION:		Entry into a Material Definitive Agreement
    ITEM INFORMATION:		Unregistered Sales of Equity Securities
    ITEM INFORMATION:		Submission of Matters to a Vote of Security Holders
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20240119
    DATE AS OF CHANGE:		20240119

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			FIRSTSUN CAPITAL BANCORP
    		CENTRAL INDEX KEY:			0001709442
    		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
    		ORGANIZATION NAME:           	02 Finance
    		IRS NUMBER:				814552413
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	333-258176
    		FILM NUMBER:		24546431

    	BUSINESS ADDRESS:
    		STREET 1:		1400 16TH STREET
    		CITY:			DENVER
    		STATE:			CO
    		ZIP:			80202
    		BUSINESS PHONE:		785-827-5565

    	MAIL ADDRESS:
    		STREET 1:		1400 16TH STREET
    		CITY:			DENVER
    		STATE:			CO
    		ZIP:			80202
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>fcb-20240115.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: fcb-20240115.htm

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    <DOCUMENT>
    <TYPE>EX-2.1
    <SEQUENCE>2
    <FILENAME>exhibit21-8xk.htm
    <DESCRIPTION>EX-2.1
    <TEXT>
    Document 2 - file: exhibit21-8xk.htm

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    <DOCUMENT>
    <TYPE>EX-4.1
    <SEQUENCE>3
    <FILENAME>exhibit41-8xk.htm
    <DESCRIPTION>EX-4.1
    <TEXT>
    Document 3 - file: exhibit41-8xk.htm

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    <DOCUMENT>
    <TYPE>EX-10.1
    <SEQUENCE>4
    <FILENAME>exhibit101-8xk.htm
    <DESCRIPTION>EX-10.1
    <TEXT>
    Document 4 - file: exhibit101-8xk.htm

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    <SEQUENCE>5
    <FILENAME>exhibit102-8xk.htm
    <DESCRIPTION>EX-10.2
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    Document 5 - file: exhibit102-8xk.htm

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    <SEQUENCE>6
    <FILENAME>exhibit103-8xk.htm
    <DESCRIPTION>EX-10.3
    <TEXT>
    Document 6 - file: exhibit103-8xk.htm

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    <SEQUENCE>7
    <FILENAME>exhibit104-8xk.htm
    <DESCRIPTION>EX-10.4
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    Document 7 - file: exhibit104-8xk.htm

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    <SEQUENCE>9
    <FILENAME>fcb-20240115.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 9 - file: fcb-20240115.xsd

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    <TYPE>EX-101.LAB
    <SEQUENCE>10
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    <TEXT>
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    <TYPE>EX-101.PRE
    <SEQUENCE>11
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    <TEXT>
    Document 11 - file: fcb-20240115_pre.xml

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    <TYPE>XML
    <SEQUENCE>12
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 12 - file: R1.htm

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    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>fcb-20240115_htm.xml
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    <TEXT>
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    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>14
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
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    <TYPE>XML
    <SEQUENCE>15
    <FILENAME>Show.js
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    <TEXT>
    Document 15 - file: Show.js

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    <TYPE>XML
    <SEQUENCE>16
    <FILENAME>report.css
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    <TEXT>
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    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>17
    <FILENAME>FilingSummary.xml
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    <TEXT>
    Document 17 - file: FilingSummary.html

    Document 17 - RAW XML: FilingSummary.xml

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    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>19
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    <TEXT>
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    <SEQUENCE>20
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    <TEXT>
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