Exhibit 4.2


 


Execution Version


 


FIRST SUPPLEMENTAL INDENTURE


 


dated as of June 26, 2020


 


to


 


SUBORDINATED DEBT INDENTURE


 


dated as of June 26, 2020


 


BYLINE BANCORP, INC.,

Company


 


and


 


U.S. BANK NATIONAL ASSOCIATION,

Trustee


 


6.000% FIXED-TO-FLOATING RATE SUBORDINATED
NOTES DUE 2030


 






     

     


    

 


Table
of Contents


 


	 	 	Page
	 	 	 
	Article I             DEFINITIONS	 	2
	 	 	 	 	 	 
	 	Section 1.1	 	Definitions	 	2
	 	 	 	 	 	 
	Article II            GENERAL TERMS AND CONDITIONS OF THE NOTES	 	9
	 	 	 	 	 	 
	 	Section 2.1	 	Designation and Principal Amount	 	9
	 	 	 	 	 	 
	 	Section 2.2	 	Form and Denomination of Notes	 	9
	 	 	 	 	 	 
	 	Section 2.3	 	Initial Limit on Amount of Series	 	9
	 	 	 	 	 	 
	 	Section 2.4	 	Rank; Subordination	 	9
	 	 	 	 	 	 
	 	Section 2.5	 	Further Issues Without Holders’ Consent	 	9
	 	 	 	 	 	 
	 	Section 2.6	 	Form and Payment	 	10
	 	 	 	 	 	 
	 	Section 2.7	 	Interest	 	10
	 	 	 	 	 	 
	 	Section 2.8	 	Redemption	 	13
	 	 	 	 	 	 
	 	Section 2.9	 	No Sinking Fund	 	14
	 	 	 	 	 	 
	 	Section 2.10	 	Notes Not Convertible or Exchangeable	 	14
	 	 	 	 	 	 
	 	Section 2.11	 	Events of Default	 	14
	 	 	 	 	 	 
	 	Section 2.12	 	Global Securities	 	14
	 	 	 	 	 	 
	 	Section 2.13	 	No Additional Amounts	 	14
	 	 	 	 	 	 
	Article III          ORIGINAL ISSUE OF NOTES	 	15
	 	 	 	 	 	 
	 	Section 3.1	 	Original Issue of Notes	 	15
	 	 	 	 	 	 
	Article IV          DEFEASANCE	 	15
	 	 	 	 	 	 
	 	Section 4.1	 	Defeasance Applicable to Notes	 	15
	 	 	 	 	 	 
	Article V           MISCELLANEOUS	 	15
	 	 	 	 	 	 
	 	Section 5.1	 	Ratification of Indenture	 	15
	 	 	 	 	 	 
	 	Section 5.2	 	Conflict with Trust Indenture Act	 	15
	 	 	 	 	 	 
	 	Section 5.3	 	Effect of Headings and Table of Contents	 	15
	 	 	 	 	 	 
	 	Section 5.4	 	Successors and Assigns	 	15
	 	 	 	 	 	 
	 	Section 5.5	 	Separability Clause	 	16
	 	 	 	 	 	 
	 	Section 5.6	 	Benefits of Indenture	 	16
	 	 	 	 	 	 
	 	Section 5.7	 	Governing Law	 	16
	 	 	 	 	 	 
	 	Section 5.8	 	Waiver of Jury Trial	 	16
	 	 	 	 	 	 
	 	Section 5.9	 	Counterparts	 	16
	 	 	 	 	 	 
	 	Section 5.10	 	Electronic Signatures	 	16
	 	 	 	 	 	 
	 	Section 5.11	 	Trustee	 	17




 



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THIS FIRST SUPPLEMENTAL
INDENTURE, dated as of June 26, 2020 (this “Supplemental Indenture”), by and between Byline Bancorp, Inc.,
a Delaware corporation having its principal place of business at 180 North LaSalle Street, Suite 300, Chicago, Illinois
60601 (hereinafter called the “Company,” which term shall include any successors and assigns pursuant to the
terms of this Supplemental Indenture), and U.S. Bank National Association, a national banking association duly organized and existing
under the laws of the United States of America, as Trustee (hereinafter called the “Trustee”).


 


WHEREAS, the
Company executed and delivered the Subordinated Debt Indenture (the “Indenture”), dated as of June 26,
2020, to the Trustee, to provide for the issuance from time to time of the Company’s unsecured subordinated notes or other
evidences of indebtedness (the “Securities”), to be issued in one or more series;


 


WHEREAS, pursuant
to the terms of the Indenture, the Company desires to provide for the establishment of a series of its Securities under the Indenture
to be known as its “6.000% Fixed-to-Floating Rate Subordinated Notes due 2030” (the “Notes”), the
form and substance of and the terms, provisions and conditions thereof to be set forth as provided in the Indenture and this Supplemental
Indenture;


 


WHEREAS, the
Board of Directors of the Company, pursuant to resolutions duly adopted on May 18 and June 9, 2020, has duly authorized
the issuance of the Notes and the amendments to the Indenture provided for in this Supplemental Indenture, and has authorized the
proper officers of the Company to execute any and all appropriate documents necessary or appropriate to effect each such issuance;


 


WHEREAS, this
Supplemental Indenture is being entered into pursuant to the provisions of Section 201, Section 301, Section 303
and Article Nine of the Indenture;


 


WHEREAS, the
Company has requested that the Trustee execute and deliver this Supplemental Indenture; and


 


WHEREAS, all
things necessary to make this Supplemental Indenture a valid agreement of the Company, in accordance with its terms, and to make
each of the Notes, when executed by the Company and authenticated and delivered by the Trustee or an authentication agent, the
valid obligations of the Company, have been performed, and the execution and delivery of this Supplemental Indenture has been duly
authorized in all respects;


 


NOW THEREFORE,
in consideration of the premises and the purchase and acceptance of the Notes by the Holders thereof, and for the purpose of setting
forth, as provided in the Indenture, the forms and terms of the Notes, the Company covenants and agrees with the Trustee, for the
equal and proportionate benefit of the Holders of the Notes, as follows:


 






     

     


    

 


Article I


 


DEFINITIONS


 


Section 1.1           Definitions.
For all purposes of this Supplemental Indenture, except as otherwise expressly provided or unless the context otherwise requires:


 


(a)          all
references in this instrument to designated “Articles,” “Sections” and other subdivisions are to be designated
Articles, Sections and other subdivisions of this instrument unless the context otherwise requires; the words “herein,”
 “hereof” and “hereunder” and other words of similar import refer to this Supplemental Indenture as a whole
and not to any particular Article, Section or other subdivision;


 


(b)          each
term defined in the Indenture has the same meaning when used in this Supplemental Indenture, except to the extent specifically
defined herein, in which case the meaning ascribed to it in this Supplemental Indenture shall control; and


 


(c)          Section 101
of the Indenture is amended and supplemented, solely with respect to the Notes, by inserting the following additional defined terms
in their appropriate alphabetical positions:


 


“Additional
Amounts” means amounts, if any, that may be required hereby or by the Notes, under circumstances specified herein or
therein, to be paid by the Company to Holders in respect of U.S. federal income tax or other tax or assessments.


 


“Administrative
or Judicial Action” has the meaning provided in the definition of “Tax Event.”


 


“Benchmark”
means, initially, Three-Month Term SOFR; provided that if the Calculation Agent determines on or prior to the Reference Time that
a Benchmark Transition Event and its related Benchmark Replacement Date have occurred with respect to Three-Month Term SOFR or
the then-current Benchmark, then “Benchmark” means the applicable Benchmark Replacement.


 


“Benchmark
Replacement” means the Interpolated Benchmark with respect to the then-current Benchmark, plus the Benchmark Replacement
Adjustment for such Benchmark; provided that if (a) the Calculation Agent cannot determine the Interpolated Benchmark as of
the Benchmark Replacement Date or (b) the then-current Benchmark is Three-Month Term SOFR and a Benchmark Transition Event
and its related Benchmark Replacement Date have occurred with respect to Three-Month Term SOFR (in which event no Interpolated
Benchmark with respect to Three-Month Term SOFR shall be determined), then “Benchmark Replacement” means the
first alternative set forth in the order below that can be determined by the Calculation Agent as of the Benchmark Replacement
Date:


 


(1)            Compounded
SOFR;


 


(2)            the
sum of: (a) the alternate rate that has been selected or recommended by the Relevant Governmental Body as the replacement
for the then-current Benchmark for the applicable Corresponding Tenor and (b) the Benchmark Replacement Adjustment;


 






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(3)            the
sum of: (a) the ISDA Fallback Rate, and (b) the Benchmark Replacement Adjustment;


 


(4)            the
sum of: (a) the alternate rate that has been selected by the Calculation Agent as the replacement for the then-current Benchmark
for the applicable Corresponding Tenor, giving due consideration to any industry-accepted rate as a replacement for the then-current
Benchmark for U.S. dollar-denominated floating rate securities at such time, and (b) the Benchmark Replacement Adjustment.


 


“Benchmark
Replacement Adjustment” means the first alternative set forth in the order below that can be determined by the Calculation
Agent as of the Benchmark Replacement Date:


 


(1)            the
spread adjustment, or method for calculating or determining such spread adjustment (which may be a positive or negative value or
zero), that has been selected or recommended by the Relevant Governmental Body for the applicable Unadjusted Benchmark Replacement;


 


(2)            if
the applicable Unadjusted Benchmark Replacement is equivalent to the ISDA Fallback Rate, then the ISDA Fallback Adjustment; and


 


(3)            the
spread adjustment (which may be a positive or negative value or zero) that has been selected by the Calculation Agent giving due
consideration to any industry-accepted spread adjustment or method for calculating or determining such spread adjustment, for the
replacement of the then-current Benchmark with the applicable Unadjusted Benchmark Replacement for U.S. dollar-denominated floating
rate securities at such time.


 


“Benchmark
Replacement Conforming Changes” means, with respect to any Benchmark Replacement, any technical, administrative or operational
changes (including changes to the definition of “interest period,” timing and frequency of determining rates with respect
to each interest period and making payments of interest, rounding of amounts or tenors, and other administrative matters) that
the Calculation Agent decides may be appropriate to reflect the adoption of such Benchmark Replacement in a manner substantially
consistent with market practice (or, if the Calculation Agent decides that adoption of any portion of such market practice is not
administratively feasible or if the Calculation Agent determines that no market practice for use of the Benchmark Replacement exists,
in such other manner as the Calculation Agent determines is reasonably necessary).


 


“Benchmark
Replacement Date” means the earliest to occur of the following events with respect to the then-current Benchmark:


 


(1)            in
the case of clause (1) of the definition of “Benchmark Transition Event,” the relevant Reference Time in
respect of any determination;


 






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(2)            in
the case of clause (2) or (3) of the definition of “Benchmark Transition Event,” the later of (a) the
date of the public statement or publication of information referenced therein and (b) the date on which the administrator
of the Benchmark permanently or indefinitely ceases to provide the Benchmark; or


 


(3)            in
the case of clause (4) of the definition of “Benchmark Transition Event,” the date of the public statement
or publication of information referenced therein.


 


For the avoidance of
doubt, for purposes of the definitions of Benchmark Replacement Date and Benchmark Transition Event, references to the Benchmark
also include any reference rate underlying the Benchmark (for example, if the Benchmark becomes Compounded SOFR, references to
the Benchmark would include SOFR).


 


For the avoidance of
doubt, if the event giving rise to the Benchmark Replacement Date occurs on the same day as, but earlier than, the Reference Time
in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for
such determination.


 


“Benchmark
Transition Event” means the occurrence of one or more of the following events with respect to the then-current Benchmark:


 


(1)            if
the Benchmark is Three-Month Term SOFR, (a) the Relevant Governmental Body has not selected or recommended a forward-looking
term rate for a tenor of three months based on SOFR, (b) the development of a forward-looking term rate for a tenor of three
months based on SOFR that has been recommended or selected by the Relevant Governmental Body is not complete or (c) the Company
determines that the use of a forward-looking rate for a tenor of three months based on SOFR is not administratively feasible;


 


(2)            a
public statement or publication of information by or on behalf of the administrator of the Benchmark announcing that such administrator
has ceased or will cease to provide the Benchmark, permanently or indefinitely, provided that, at the time of such statement or
publication, there is no successor administrator that will continue to provide the Benchmark;


 


(3)            a
public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark, the central
bank for the currency of the Benchmark, an insolvency official with jurisdiction over the administrator for the Benchmark, a resolution
authority with jurisdiction over the administrator for the Benchmark or a court or an entity with similar insolvency or resolution
authority over the administrator for the Benchmark, which states that the administrator of the Benchmark has ceased or will cease
to provide the Benchmark permanently or indefinitely, provided that, at the time of such statement or publication, there is no
successor administrator that will continue to provide the Benchmark; or


 


(4)            a
public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark announcing that
the Benchmark is no longer representative.


 






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“Business
Day” means any day, other than a Saturday or Sunday, that is neither a legal holiday nor a day on which banking institutions
in The City of New York or in the city where the Corporate Trust Office of the Trustee is located are authorized or required by
law, regulation or executive order to close.


 


“Calculation
Agent” means the agent appointed by the Company prior to the commencement of the Floating Rate Period (which may include
the Company or any of its Affiliates) to act in accordance with Section 2.7. The Company shall initially act as the Calculation
Agent.


 


“Compounded
SOFR” means the compounded average of SOFRs for the applicable Corresponding Tenor, with the rate, or methodology for
this rate, and conventions for this rate being established by the Calculation Agent in accordance with:


 


(1)            the
rate, or methodology for this rate, and conventions for this rate selected or recommended by the Relevant Governmental Body for
determining compounded SOFR; provided that:


 


(2)            if,
and to the extent that, the Calculation Agent determines that Compounded SOFR cannot be determined in accordance with clause (1) above,
then the rate, or methodology for this rate, and conventions for this rate that have been selected by the Calculation Agent giving
due consideration to any industry-accepted market practice for U.S. dollar-denominated floating rate securities at such time.


 


For the avoidance of
doubt, the calculation of Compounded SOFR shall exclude the Benchmark Replacement Adjustment (if applicable) and the spread of
588 basis points per annum.


 


“Corresponding
Tenor” with respect to a Benchmark Replacement means a tenor (including overnight) having approximately the same length
(disregarding business day adjustment) as the applicable tenor for the then-current Benchmark.


 


“DTC”
means The Depository Trust Company.


 


“Federal
Reserve” has the meaning provided in the definition of “Tier 2 Capital Event.”


 


“Federal
Reserve Bank of New York’s Website” means the website of the Federal Reserve Bank of New York at http://www.newyorkfed.org,
or any successor source.


 


“Fixed
Rate Interest Payment Date” has the meaning provided in Section 2.7(a).


 


“Fixed
Rate Period” has the meaning provided in Section 2.7(a).


 


“Fixed
Rate Regular Record Date” has the meaning provided in Section 2.7(a).


 






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“Floating
Rate Interest Payment Date” has the meaning provided in Section 2.7(b).


 


“Floating
Rate Period” has the meaning provided in Section 2.7(b).


 


“Floating
Rate Regular Record Date” has the meaning provided in Section 2.7(b).


 


“Interest
Payment Date” has the meaning provided in Section 2.7(b).


 


“interest
period” means the period from and including the immediately preceding Interest Payment Date in respect of which interest
has been paid or duly provided for or, if no interest has been paid or duly provided for, from and including the Issue Date to,
but excluding, the applicable Interest Payment Date or the Maturity Date or date of earlier redemption, if applicable.


 


“Interpolated
Benchmark” with respect to the Benchmark means the rate determined for the Corresponding Tenor by interpolating on a
linear basis between: (1) the Benchmark for the longest period (for which the Benchmark is available) that is shorter than
the Corresponding Tenor, and (2) the Benchmark for the shortest period (for which the Benchmark is available) that is longer
than the Corresponding Tenor.


 


“ISDA
Definitions” means the 2006 ISDA Definitions published by the International Swaps and Derivatives Association, Inc.
or any successor thereto, as amended or supplemented from time to time, or any successor definitional booklet for interest rate
derivatives published from time to time.


 


“ISDA
Fallback Adjustment” means the spread adjustment (which may be a positive or negative value or zero) that would apply
for derivatives transactions referencing the ISDA Definitions to be determined upon the occurrence of an index cessation event
with respect to the Benchmark for the applicable tenor.


 


“ISDA
Fallback Rate” means the rate that would apply for derivatives transactions referencing the ISDA Definitions to be effective
upon the occurrence of an index cessation date with respect to the Benchmark for the applicable tenor excluding the applicable
ISDA Fallback Adjustment.


 


“Issue
Date” means June 26, 2020.


 


“Maturity
Date” has the meaning provided in Section 2.2.


 


“Redemption
Date” has the meaning provided in Section 2.8.


 


“Reference
Time” with respect to any determination of the Benchmark means (1) if the Benchmark is Three-Month Term SOFR, the
time determined by the Calculation Agent after giving effect to the Three-Month Term SOFR Conventions, and (2) if the Benchmark
is not Three-Month Term SOFR, the time determined by the Calculation Agent after giving effect to the Benchmark Replacement Conforming
Changes.


 






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“Relevant
Governmental Body” means the Federal Reserve and/or the Federal Reserve Bank of New York, or a committee officially endorsed
or convened by the Federal Reserve and/or the Federal Reserve Bank of New York or any successor thereto.


 


“Senior
Indebtedness” means (i) the principal and any premium or interest for money borrowed or purchased by the Company,
including but not limited to indebtedness evidenced by bonds, debentures, notes or similar instruments; (ii) an obligation
arising from off-balance sheet guarantees and direct credit substitutes; (iii) reimbursement obligations with respect to letters
of credit, bankers’ acceptances or similar facilities; (iv) obligations issued or assumed as the deferred purchase price
of property or services (but excluding trade accounts payable or accrued liabilities arising in the ordinary course of business);
(v) capital lease obligations; (vi) any obligations associated with derivative products including but not limited to
securities contracts, foreign currency exchange contracts, swap agreements (including interest rate and foreign exchange rate swap
agreements), cap agreements, floor agreements, collar agreements, interest rate agreements, foreign exchange rate agreements, options,
commodity futures contracts, commodity option contracts and similar financial instruments; (vii) debt of others described
in the preceding clauses that we have guaranteed or for which we are otherwise liable or that are secured by any lien on any of
our property or assets; and (viii) obligations to general creditors, in each case, whether outstanding on the date this Indenture
becomes effective, or created, assumed or incurred after that date, unless in the instrument creating or evidencing any such indebtedness
or obligation, or pursuant to which the same is outstanding, it is provided that such indebtedness or obligation is not superior
in right of payment to the Notes or to other debt that is pari passu with or subordinate to the Notes.


 


Senior Indebtedness
excludes any (i) trade accounts payables arising in the ordinary course of the Company’s business; (ii) any indebtedness
of the Company that when incurred and without respect to any election under Section 1111(b) of the United States Bankruptcy
Code of 1978, as amended, was without recourse to the Company; (iii) any indebtedness to an employee of the Company; or (iv) indebtedness
that expressly states that it is junior to, or ranks equally in right of payment with, the Notes.


 


“SOFR”
means the secured overnight financing rate published by the Federal Reserve Bank of New York, as the administrator of the Benchmark
(or a successor administrator), on the Federal Reserve Bank of New York’s Website.


 


“Tax
Event” means the receipt by the Company of an opinion of independent tax counsel to the effect that as a result of (a) an
amendment to or change (including any announced prospective amendment or change) in any law or treaty, or any regulation thereunder,
of the United States or any of its political subdivisions or taxing authorities; (b) a judicial decision, administrative action,
official administrative pronouncement, ruling, regulatory procedure, regulation, notice or announcement, including any notice or
announcement of intent to adopt or promulgate any ruling, regulatory procedure or regulation (any of the foregoing, an “Administrative
or Judicial Action”); or (c) an amendment to or change in any official position with respect to, or any interpretation
of, an Administrative or Judicial Action or a law or regulation of the United States that differs from the previously generally
accepted position or interpretation, in each case, which change or amendment or challenge becomes effective or which pronouncement,
decision or challenge is announced on or after the original issue date of the Notes, there is more than an insubstantial risk that
interest payable by the Company on the Notes is not, or, within 90 days of the date of such opinion, will not be, deductible by
the Company, in whole or in part, for United States federal income tax purposes.


 






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“Term
SOFR” means the forward-looking term rate based on SOFR that has been selected or recommended by the Relevant Governmental
Body.


 


“Term
SOFR Administrator” means any entity designated by the Relevant Governmental Body as the administrator of Term SOFR (or
a successor administrator).


 


“Three-Month
Term SOFR” means the rate for Term SOFR for a tenor of three months that is published by the Term SOFR Administrator
at the Reference Time for any interest period, as determined by the Calculation Agent after giving effect to the Three-Month Term
SOFR Conventions. All percentages used in or resulting from any calculation of Three-Month Term SOFR shall be rounded, if necessary,
to the nearest one-hundred-thousandth of a percentage point, with 0.000005% rounded up to 0.00001%.


 


“Three-Month
Term SOFR Conventions” means any determination, decision or election with respect to any technical, administrative or
operational matter (including with respect to the manner and timing of the publication of Three-Month Term SOFR, or changes to
the definition of “interest period,” timing and frequency of determining Three-Month Term SOFR with respect to each
interest period and making payments of interest, rounding of amounts or tenors, and other administrative matters) that the Calculation
Agent decides may be appropriate to reflect the use of Three-Month Term SOFR as the Benchmark in a manner substantially consistent
with market practice (or, if the Calculation Agent decides that adoption of any portion of such market practice is not administratively
feasible or if the Calculation Agent determines that no market practice for the use of Three-Month Term SOFR exists, in such other
manner as the Calculation Agent determines is reasonably necessary).


 


“Tier
2 Capital Event” means the Company’s good faith determination that, as a result of (a) any amendment to, or
change in, the laws, rules or regulations of the United States (including, for the avoidance of doubt, any agency or instrumentality
of the United States, including the Federal Reserve and other federal bank regulatory agencies) or any political subdivision of
or in the United States that is enacted or becomes effective after the original issue date of the Notes; (b) any proposed
change in those laws, rules or regulations that is announced or becomes effective after the original issue date of the Notes;
or (c) any official administrative decision or judicial decision or administrative action or other official pronouncement
interpreting or applying those laws, rules, regulations, policies or guidelines with respect thereto that is announced after the
original issue date of the Notes, there is more than an insubstantial risk that the Company will not be entitled to treat the Notes
then outstanding as “Tier 2 Capital” (or its equivalent) for purposes of the capital adequacy rules or regulations
of the Board of Governors of the Federal Reserve System (the “Federal Reserve”) (or, as and if applicable, the
capital adequacy rules or regulations of any successor appropriate federal banking agency) as then in effect and applicable
to the Company, for so long as any Notes are outstanding.


 


“Unadjusted
Benchmark Replacement” means the Benchmark Replacement excluding the Benchmark Replacement Adjustment.


 






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Article II


 


GENERAL
TERMS AND CONDITIONS OF THE NOTES


 


Section 2.1           Designation
and Principal Amount. There is hereby authorized and established a series of Securities under the Indenture, designated as
the “6.000% Fixed-to-Floating Rate Subordinated Notes due 2030.”


 


Section 2.2           Form and
Denomination of Notes. The definitive form of the Notes and the Trustee’s Certificate of Authentication to be endorsed
thereon shall be substantially in the form set forth in Exhibit A attached hereto, which is incorporated herein and made part
hereof. The Notes shall bear interest and have such other terms as are stated in the form of definitive Notes or in the Indenture,
as supplemented by this Supplemental Indenture. The stated maturity of the Notes shall be July 1, 2030 (the “Maturity
Date”). The Notes shall be issued in denominations of $1,000 and integral multiples of $1,000 in excess thereof.


 


Section 2.3           Initial
Limit on Amount of Series. The Notes shall initially be limited to U.S. $50,000,000 in aggregate principal amount, and may,
upon the execution and delivery of this Supplemental Indenture or from time to time thereafter, be executed by the Company and
delivered to the Trustee for authentication, and the Trustee shall thereupon authenticate and deliver said Notes to or upon the
delivery of a Company Order. Following the initial issuance of the Notes, the aggregate principal amount of Notes may be increased
as provided in Section 2.5 hereof.


 


Section 2.4           Rank;
Subordination. The Notes are unsecured and shall rank subordinate and junior, to the extent and in the manner set forth in
the Indenture, in right of payment and upon liquidation of all the Company’s obligations to the holders of Senior Indebtedness
of the Company. The Notes shall rank equally among themselves and with all of the Company’s other subordinated unsecured
indebtedness that, in the instrument creating or evidencing the same or pursuant to which the same is outstanding, provides that
such obligations are not superior in right of payment to the Notes or to other indebtedness that is pari passu with, or
is not subordinate to, the Notes; provided that that the Notes shall rank senior to (i) the Company’s obligations relating
to any junior subordinated debt securities issued to the Company’s capital trust subsidiaries, and (ii) the Company’s
future indebtedness the terms of which provide that such indebtedness ranks junior to the Notes . It is intended that the Notes
be and are Tier 2 capital or the equivalent, for all regulatory purposes.


 


Section 2.5           Further
Issues Without Holders’ Consent. The Company may, without notice to or the consent of the Holders of the Notes, but in
compliance with the terms of the Indenture and this Supplemental Indenture, create and issue additional Notes having the same ranking,
interest rate, maturity date and other terms as the Notes (other than the date of issuance, the issue price, the initial interest
accrual date and the first Interest Payment Date). Any such additional Notes will rank equally and ratably with the Notes. Any
such additional Notes, together with the Notes initially issued hereunder, will constitute a single series of Securities for all
purposes under the Indenture. Notwithstanding anything to the contrary in the foregoing, no additional Notes may be issued unless
(1) the additional Notes will be fungible with the Notes initially issued hereunder for United States securities law purposes,
(2) (a) the additional Notes are issued pursuant to a “qualified reopening” of the Notes initially issued
hereunder for United States federal income tax purposes, or (b) the Notes initially issued hereunder were, and the additional
Notes are, issued without any original issue discount for United States federal income tax purposes and (3) the additional
Notes have the same CUSIP number as the Notes initially issued hereunder. No additional Notes may be issued if any Default has
occurred and is continuing with respect to the Notes.


 






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Section 2.6           Form and
Payment. Principal of, Additional Amounts, if any, and interest on the Notes shall be payable in U.S. Dollars.


 


Section 2.7           Interest.


 


(a)          The
Notes will bear interest at a fixed rate of 6.000% per annum from and including June 26, 2020 to, but excluding, July 1,
2025 or earlier Redemption Date (the “Fixed Rate Period”). Interest accrued on the Notes during the Fixed Rate
Period will be payable semi-annually in arrears on January 1 and July 1 of each year, commencing on January 1, 2021
(each such date, a “Fixed Rate Interest Payment Date”). The last Fixed Rate Interest Payment Date shall be July 1,
2025, unless the Notes are earlier redeemed. The interest payable during the Fixed Rate Period will be paid to each Holder in whose
name a Note is registered at the close of business on the fifteenth day (whether or not a Business Day) immediately preceding the
applicable Fixed Rate Interest Payment Date (each such date, a “Fixed Rate Regular Record Date”).


 


(b)          The
Notes will bear a floating interest rate from, and including July 1, 2025, to, but excluding, the Maturity Date or earlier
Redemption Date (the “Floating Rate Period”). The floating interest rate will be reset quarterly, and the interest
rate for any Floating Rate Period shall be equal to the then-current Three-Month Term SOFR plus 588 basis points for each quarterly
interest period during the Floating Rate Period. During the Floating Rate Period, interest on the Notes will be payable quarterly
in arrears on January 1, April 1, July 1 and October 1 of each year, commencing on October 1, 2025 (each
such date, a “Floating Rate Interest Payment Date” and, together with a Fixed Rate Interest Payment Date, an
 “Interest Payment Date”). The interest payable during the Floating Rate Period will be paid to each Holder in
whose name a Note is registered at the close of business on the fifteenth day (whether or not a Business Day) immediately preceding
the applicable Floating Rate Interest Payment Date (each such date, a “Floating Rate Regular Record Date”).
Notwithstanding the foregoing, if Three-Month Term SOFR (or other applicable Benchmark) is less than zero, then Three-Month Term
SOFR (or other such Benchmark) shall be deemed to be zero. The Calculation Agent will provide the Company and the Trustee with
the interest rate in effect on the Notes promptly after the Reference Time (or such other date of determination for the applicable
Benchmark).


 






    	 	10	 



     


    

 


(c)          The
amount of interest payable on any Fixed Rate Interest Payment Date during the Fixed Rate Period will be computed on the basis of
a 360-day year consisting of twelve 30-day months to, but excluding, July 1, 2025, and, the amount of interest payable on
any Floating Rate Interest Payment Date during the Floating Rate Period will be computed on the basis of a 360-day year on the
basis of the actual number of days elapsed. The Company or the Calculation Agent, as applicable, shall calculate the amount of
interest payable on any Interest Payment Date and the Trustee shall have no duty to confirm or verify any such calculation. In
the event that any scheduled Interest Payment Date or the Maturity Date for the Notes falls on a day that is not a Business Day,
then payment of interest payable on such Interest Payment Date or of principal and interest payable on the Maturity Date will be
paid on the next succeeding day which is a Business Day (any payment made on such date will be treated as being made on the date
that the payment was first due and no interest on such payment will accrue for the period from and after such scheduled Interest
Payment Date); provided, that in the event that any scheduled Floating Rate Interest Payment Date falls on a day that is not a
Business Day and the next succeeding Business Day falls in the next succeeding calendar month, such Floating Rate Interest Payment
Date will be accelerated to the immediately preceding Business Day, and, in each such case, the amounts payable on such Business
Day will include interest accrued to, but excluding, such Business Day. Dollar amounts resulting from interest calculations will
be rounded to the nearest cent, with one half cent being rounded upward.


 


(d)          The
Company shall take such actions as are necessary to ensure that from the commencement of the Floating Rate Period for so long as
any of the Notes remain outstanding there will at all times be a Calculation Agent appointed to calculate Three-Month Term SOFR
in respect of each Floating Rate Period. The calculation of Three-Month Term SOFR for each applicable Floating Rate Period by the
Calculation Agent will (in the absence of manifest error) be final and binding. The Calculation Agent’s determination of
any interest rate and its calculation of interest payments for any period will be maintained on file at the Calculation Agent’s
principal offices, will be made available to any Holder of the Notes upon request and will be provided to the Trustee. The Calculation
Agent shall have all the rights, protections and indemnities afforded to the Trustee under the Indenture and hereunder. The Calculation
Agent may be removed by the Company at any time. If the Calculation Agent is unable or unwilling to act as Calculation Agent or
is removed by the Company, the Company will promptly appoint a replacement Calculation Agent. The Calculation Agent may not resign
its duties without a successor having been duly appointed; provided, that if a successor Calculation Agent has not been appointed
by the Company and such successor accepted such position within 30 days after the giving of notice of resignation by the Calculation
Agent, then the resigning Calculation Agent may petition, at the expense of the Company, any court of competent jurisdiction for
the appointment of a successor Calculation Agent with respect to such series. The Trustee shall not be under any duty to succeed
to, assume or otherwise perform, any duties of the Calculation Agent, or to appoint a successor or replacement in the event of
the Calculation Agent’s resignation or removal or to replace the Calculation Agent in the event of a default, breach or failure
of performance on the part of the Calculation Agent with respect to the Calculation Agent’s duties and obligations hereunder.
For the avoidance of doubt, if at any time there is no Calculation Agent appointed by the Company, then the Company shall be the
Calculation Agent. The Company may appoint itself or any of its Affiliates to be the Calculation Agent.


 






    	 	11	 



     


    

 


(e)          Effect
of Benchmark Transition Event.


 


(1)            If
the Calculation Agent determines that a Benchmark Transition Event and its related Benchmark Replacement Date have occurred on
or prior to the Reference Time in respect of any determination of the Benchmark on any date, then the Benchmark Replacement will
replace the then-current Benchmark for all purposes relating to the Notes during the Floating Rate Period in respect of such determination
on such date and all determinations on all subsequent dates. In connection with the implementation of a Benchmark Replacement,
the Calculation Agent will have the right to make Benchmark Replacement Conforming Changes from time to time.


 


(2)            Notwithstanding
anything set forth in Section 2.7(b) above, if the Calculation Agent determines on or prior to the relevant Reference
Time that a Benchmark Transition Event and its related Benchmark Replacement Date have occurred with respect to Three-Month Term
SOFR, then the provisions set forth in this Section 2.7(e) will thereafter apply to all determinations of the interest
rate on the Notes during the Floating Rate Period. After a Benchmark Transition Event and its related Benchmark Replacement Date
have occurred, the interest rate on the Notes for each interest period during the Floating Rate Period will be an annual rate equal
to the Benchmark Replacement plus 588 basis points.


 


(3)            The
Calculation Agent is expressly authorized to make certain determinations, decisions and elections under the terms of the Notes,
including with respect to the use of Three-Month Term SOFR as the Benchmark and under this Section 2.7(e). Any determination,
decision or election that may be made by the Calculation Agent under the terms of the Notes, including any determination with respect
to a tenor, rate or adjustment or of the occurrence or non-occurrence of an event, circumstance or date and any decision to take
or refrain from taking any action or selection (A) will be conclusive and binding on the Holders of the Notes and the Trustee
absent manifest error, (B) if made by the Company as Calculation Agent, will be made in the Company’s sole discretion,
(C) if made by a Calculation Agent other than the Company, will be made after consultation with the Company, and the Calculation
Agent will not make any such determination, decision or election to which the Company reasonably objects and (D) notwithstanding
anything to the contrary herein or in the Indenture, shall become effective without consent from the Holders of the Notes, the
Trustee or any other party. If the Calculation Agent fails to make any determination, decision or election that it is required
to make under the terms of the Notes, then the Company will make such determination, decision or election on the same basis as
described above.


 


(4)            The
Company (or its Calculation Agent) shall notify the Trustee in writing (i) upon the occurrence of the Benchmark Transition
Event or the Benchmark Replacement Date, and (ii) of any Benchmark Replacements, Benchmark Replacement Conforming Changes
and other items affecting the interest rate on the Notes after a Benchmark Transition Event.


 






    	 	12	 



     


    

 


(5)            The
Trustee (including in its capacity as Paying Agent) shall have no (i) responsibility or liability for the (A) Three-Month
Term SOFR Conventions, (B) selection of an alternative reference rate to Three-Month Term SOFR (including, without limitation,
whether the conditions for the designation of such rate have been satisfied or whether such rate is a Benchmark Replacement or
an Unadjusted Benchmark Replacement), (C) determination or calculation of a Benchmark Replacement, or (D) determination
of whether a Benchmark Transition Event or Benchmark Replacement Date has occurred, and in each such case under clauses (A) through
(D) above shall be entitled to conclusively rely upon the selection, determination, and/or calculation thereof as provided
by the Company or its Calculation Agent, as applicable, and (ii) liability for any failure or delay in performing its duties
hereunder as a result of the unavailability of a Benchmark rate as described in the definition thereof, including, without limitation,
as a result of the Company’s or Calculation Agent’s failure to select a Benchmark Replacement or the Calculation Agent’s
failure to calculate a Benchmark. The Trustee shall be entitled to rely conclusively on all notices from the Company or its Calculation
Agent regarding any Benchmark or Benchmark Replacement, including, without limitation, in regards to Three-Month Term SOFR Conventions,
a Benchmark Transition Event, Benchmark Replacement Date, and Benchmark Replacement Conforming Changes. The Trustee shall not be
responsible or liable for the actions or omissions of the Calculation Agent, or any failure or delay in the performance of the
Calculation Agent’s duties or obligations, nor shall it be under any obligation to monitor or oversee the performance of
the Calculation Agent. The Trustee shall be entitled to conclusively rely on any determination made, and any instruction, notice,
Officers’ Certificate or other instruction or information provided by the Calculation Agent without independent verification,
investigation or inquiry of any kind. The Trustee shall not be obligated to enter into any amendment or supplement hereto that
adversely impacts its rights, duties, obligations, immunities or liabilities (including, without limitation, in connection with
the adoption of any Benchmark Replacement Conforming Changes).


 


(6)            If
the then-current Benchmark is Three-Month Term SOFR, the Calculation Agent will have the right to establish the Three-Month Term
SOFR Conventions, and if any of the foregoing provisions concerning the calculation of the interest rate and the payment of interest
during the Floating Rate Period are inconsistent with any of the Three-Month Term SOFR Conventions determined by the Calculation
Agent, then the relevant Three-Month Term SOFR Conventions will apply.


 


Section 2.8           Redemption.


 


(a)          The
Notes shall be redeemable, in each case, in whole or in part from time to time, at the option of the Company beginning with the
Interest Payment Date on July 1, 2025 but not prior thereto (except upon the occurrence of certain events specified below),
and on any Interest Payment Date thereafter (each, a “Redemption Date”), subject to obtaining the prior approval
of the Federal Reserve to the extent such approval is then required under the rules of the Federal Reserve. The Notes may
not otherwise be redeemed prior to the Maturity Date, except that the Company may, at its option, redeem the Notes before the Maturity
Date, in whole, but not in part, subject to obtaining the prior approval of the Federal Reserve to the extent such approval is
then required under the rules of the Federal Reserve, upon the occurrence of a Tier 2 Capital Event or a Tax Event, or if
the Company is required to register as an investment company pursuant to the Investment Company Act of 1940, as amended (15 U.S.C.
80a-1 et seq.). Any such redemption will be at a Redemption Price equal to 100% of the principal amount of the Notes to be redeemed,
plus accrued and unpaid interest to, but excluding, the Redemption Date fixed by the Company. The provisions of Article Eleven
of the Indenture shall apply to any redemption of the Notes pursuant to this Section 2.8. Any partial redemption will be made
in accordance with DTC’s applicable procedures among all of the Holders of the Notes. If any Note is to be redeemed in part
only, the notice of redemption relating to such Note shall state that it is a partial redemption and the portion of the principal
amount thereof to be redeemed, and a replacement Note in principal amount equal to the unredeemed portion thereof will be issued
in the name of the Holder thereof upon cancellation of the original Note.


 






    	 	13	 



     


    

 


(b)          Any
notice of redemption provided to the Holders of the Notes may be conditional in the Company’s discretion, and the Company
may delay the Redemption Date until such time as any or all of such conditions have been satisfied or revoked by the Company if
it determines that such conditions will not be satisfied. The Company will provide written notice to the Trustee prior to the close
of business two Business Days prior to the Redemption Date (or such shorter period as may be acceptable to the Trustee) if any
such redemption has been rescinded or delayed, and upon receipt the Trustee will provide such notice to each Holder of the Notes
in the same manner in which the notice of redemption was given.


 


Section 2.9           No
Sinking Fund. No sinking fund will be provided with respect to the Notes. In no event shall any Holder of the Notes have the
right to require the Company to call, redeem or repurchase the Notes, in whole or in part. Nothing in this Section 2.9 shall
limit the ability of Holders of Notes to enforce their rights to the payment of principal, Additional Amounts, if any, and interest
on the Notes at maturity as provided in the Notes and in the Indenture, including Section 507 of the Indenture.


 


Section 2.10         Notes
Not Convertible or Exchangeable. The Notes will not be convertible or exchangeable for other securities or property.


 


Section 2.11         Events
of Default. Only the Events of Default described in clauses (1) and (2) of Section 501 of the Indenture
shall permit acceleration of the maturity of the Notes, as provided in Section 502 of the Indenture.


 


Section 2.12         Global
Securities. The Notes shall be issued as registered securities and in the form of one or more permanent global Securities,
without coupons, registered in the name of the Depository or its nominee. The initial Depository for the Notes shall be DTC. Except
as otherwise provided in Section 305 of the Indenture, the global Securities described above may be transferred by the Depository,
in whole but not in part, only to a nominee of the Depository, or by a nominee of the Depository to the Depository, or to a successor
Depository or to a nominee of such successor Depository.


 


Owners of beneficial
interests in such global Securities will not be considered the Holders thereof for any purpose under the Indenture. The rights
of owners of beneficial interests in such global Securities shall be exercised only through the Depository.


 


Section 2.13         No
Additional Amounts. In the event that any payment on the Notes is subject to withholding of any U.S. federal income tax or
other tax or assessment (as a result of a change in law or otherwise), the Company will not pay Additional Amounts with respect
to such tax or assessment.


 






    	 	14	 



     


    

 


Article III


 


ORIGINAL
ISSUE OF NOTES


 


Section 3.1           Original
Issue of Notes. The Notes may, upon execution of this Supplemental Indenture, be executed by the Company and delivered to the
Trustee for authentication, and the Trustee shall, upon Company Order, authenticate and deliver such Notes as in such Company Order
provided.


 


Article IV


 


DEFEASANCE


 


Section 4.1           Defeasance
Applicable to Notes. Pursuant to Section 301(xvi) and Section 1401 of the Indenture, provision is hereby made
for defeasance of the Notes under Sections 1402 and 1403 of the Indenture upon the terms and conditions contained in Article Fourteen
of the Indenture.


 


Article V


 


MISCELLANEOUS


 


Section 5.1           Ratification
of Indenture. The Indenture, as supplemented by this Supplemental Indenture, is in all respects ratified and confirmed, and
this Supplemental Indenture shall be deemed part of the Indenture in the manner and to the extent herein and therein provided;
provided, however, that the provisions of this Supplemental Indenture shall apply solely with respect to the Notes and shall
govern in the event of any difference with the Indenture.


 


Section 5.2           Conflict
with Trust Indenture Act. If any provision hereof limits, qualifies or conflicts with a provision of the Trust Indenture Act
that is required under such Act to be a part of and govern this Indenture, the latter provision shall control. If any provision
of this Supplemental Indenture modifies or excludes any provision of the Trust Indenture Act that may be so modified or excluded,
the latter provision shall be deemed to apply to this Indenture as so modified or to be excluded, as the case may be.


 


Section 5.3           Effect
of Headings and Table of Contents. The Article and Section headings herein and the Table of Contents are for convenience
only and shall not affect the construction hereof.


 


Section 5.4           Successors
and Assigns. All covenants and agreements in this Supplemental Indenture by the Company shall bind its successors and assigns,
whether expressed or not.


 






    	 	15	 



     


    

 


Section 5.5           Separability
Clause. In case any provision in this Supplemental Indenture or in the Notes shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.


 


Section 5.6           Benefits
of Indenture. Nothing in this Supplemental Indenture or in the Notes, express or implied, shall give to any Person, other than
the Holders of the Securities, the parties hereto and their successors hereunder, any benefit of any legal or equitable right,
remedy or claim under this Supplemental Indenture.


 


Section 5.7           Governing
Law. This Supplemental Indenture and the Notes shall be governed by and construed in accordance with the laws of the State
of New York. The Company irrevocably consents and agrees that any legal action, suit or proceeding against it with respect to any
matter arising out of or in connection with this Supplemental Indenture or the Securities may be brought in the courts of the State
of New York or the courts of the United States located in the Borough of Manhattan, New York, New York.


 


Section 5.8           Waiver
of Jury Trial. EACH OF THE COMPANY, THE TRUSTEE AND EACH HOLDER OF A SECURITY BY ITS ACCEPTANCE THEREOF, HEREBY IRREVOCABLY
WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT IT MAY HAVE TO TRIAL BY JURY IN ANY LEGAL PROCEEDING
DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS SUPPLEMENTAL INDENTURE, THE SECURITIES, THE INDENTURE OR THE TRANSACTIONS
CONTEMPLATED HEREBY OR THEREBY.


 


Section 5.9           Counterparts.
This Supplemental Indenture may be executed in several counterparts, each of which shall be an original and all of which shall
constitute but one and the same instrument. Each signed copy shall be an original, but all of them together represent the same
agreement. The exchange of copies of this Supplemental Indenture and of signature pages by facsimile or PDF transmission shall
constitute effective execution and delivery of this Supplemental Indenture as to the parties hereto and may be used in lieu of
the original Supplemental Indenture for all purposes. Signatures of the parties hereto transmitted by facsimile or PDF shall be
deemed to be their original signatures for all purposes.


 


Section 5.10         Electronic
Signatures. All notices, approvals, consents, requests and any communications hereunder must be in writing, provided that any
communications sent to Trustee hereunder must be in the form of a document that is signed manually or by way of a digital signature
provided by DocuSign (or such other digital signature provider as specified in writing to Trustee by the authorized representative),
in English. The Company agrees to assume all risks arising out of the use of using digital signatures and electronic methods to
submit communications to Trustee, including without limitation the risk of Trustee acting on unauthorized instructions, and the
risk of interception and misuse by third parties.


 






    	 	16	 



     


    

 


Section 5.11         Trustee.
The Trustee shall not be responsible for and makes no representation as to the validity, sufficiency or adequacy of this Supplemental
Indenture or the Notes, and it shall not be responsible for any statement of the Company in this Supplemental Indenture or in the
Notes. The Trustee makes no representations with respect to the effectiveness or adequacy of this Supplemental Indenture. The Trustee
shall not be accountable for the use or application by the Company of the Notes or the proceeds thereof.


 


[Signature page follows on next
page]


 









    	 	17	 



     


    

 


IN WITNESS WHEREOF,
the parties hereto have caused this Supplemental Indenture to be duly executed all as of the day and year first above written.


 


	 	BYLINE BANCORP, INC.
	 	 
	 	 
	 	By:	/s/ Alberto J. Paracchini
	 	Name:	Alberto J. Paracchini
	 	Title:	President and Chief Executive Officer
	 	 	 
	 	U.S. BANK NATIONAL ASSOCIATION,
    as Trustee
	 	 
	 	 
	 	By:	/s/ Linda Garcia
	 	Name:	Linda Garcia
	 	Title:	Vice President





 


[Signature page to First Supplemental
Indenture]


 









    	 	18	 



     


    

 


Exhibit A


 


FORM OF
NOTE


 


BYLINE
BANCORP, INC.

6.000% FIXED-TO-FLOATING RATE SUBORDINATED NOTE DUE JULY 1, 2030


 


	No. 1	$50,000,000


 


CUSIP No. 124411AA7


ISIN No. US124411AA74


 


THIS SECURITY IS A
GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF CEDE & CO.,
THE NOMINEE OF THE DEPOSITORY TRUST COMPANY (THE “DEPOSITORY”). EXCEPT AS OTHERWISE PROVIDED IN SECTION 305
OF THE INDENTURE, THIS SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY
OR BY A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE DEPOSITORY OR BY THE DEPOSITORY OR ANY SUCH NOMINEE
TO A SUCCESSOR DEPOSITORY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITORY.


 


UNLESS THIS SECURITY
IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”),
TO BYLINE BANCORP, INC. (the “COMPANY”) OR ITS AGENT FOR
REGISTRATION OR TRANSFER, EXCHANGE OR PAYMENT, AND ANY SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH
OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR SUCH OTHER ENTITY
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.


 


THIS SECURITY IS
NOT A DEPOSIT AND IT IS NOT INSURED BY THE FEDERAL DEPOSIT INSURANCE CORPORATION (“FDIC”) OR ANY
OTHER GOVERNMENT AGENCY.


 


THIS SECURITY IS SUBORDINATED,
AS TO PRINCIPAL, INTEREST AND PREMIUM, AND ADDITIONAL AMOUNTS, IF ANY, TO ALL “SENIOR INDEBTEDNESS” OF THE
COMPANY, INCLUDING ALL OBLIGATIONS TO THE COMPANY’S GENERAL CREDITORS (OTHER THAN OBLIGATIONS TO TRADE CREDITORS INCURRED
IN THE ORDINARY COURSE OF THE COMPANY’S BUSINESS). THIS SECURITY IS NOT SECURED BY ANY ASSETS OF THE COMPANY OR BY THE ASSETS
OF ANY OF ITS SUBSIDIARIES OR AFFILIATES, AND IS NOT GUARANTEED BY ANY OF THE COMPANY’S SUBSIDIARIES OR AFFILIATES.


 






    	 	Exhibit A – Page 1	 



     


    

 


THIS SECURITY IS ISSUABLE
IN DENOMINATIONS OF $1,000 AND INTEGRAL MULTIPLES OF $1,000 IN EXCESS THEREOF. AS PROVIDED IN THE INDENTURE AND SUBJECT TO CERTAIN
LIMITATIONS THEREIN SET FORTH, SECURITIES OF THIS SERIES ARE EXCHANGEABLE FOR A LIKE AGGREGATE PRINCIPAL AMOUNT OF SECURITIES OF
SUCH SERIES OF A DIFFERENT AUTHORIZED DENOMINATION, AS REQUESTED BY THE HOLDER SURRENDERING THE SAME.


 


Byline Bancorp, Inc.,
a Delaware corporation, and any successor thereto, as provided below (the “Company”), for value received, hereby
promises to pay or deliver, as the case may be, to CEDE & CO., or registered assigns, the principal sum of Fifty Million
United States Dollars ($50,000,000) on July 1, 2030 (the “Stated Maturity Date”), unless redeemed
prior to such date. This Security will bear interest at a fixed rate of 6.000% per annum from and including June 26, 2020,
to, but excluding, July 1, 2025 (the “Fixed Rate Period”), unless redeemed prior to such date. Interest
accrued on this Security during the Fixed Rate Period will be payable semi-annually in arrears on January 1 and July 1
of each year (each such date, a “Fixed Rate Interest Payment Date”), with the first such Fixed Rate Interest
Payment Date being January 1, 2021, and the last such Fixed Rate Interest Payment Date being July 1, 2025, unless redeemed
prior to such date. This Security will bear interest at a floating per annum interest rate from and including July 1, 2025,
to, but excluding, the Stated Maturity Date or any earlier redemption date (the “Floating Rate Period”). The
floating interest rate will be reset quarterly, and the interest rate for any Floating Interest Period will be equal to the then-current
Benchmark plus 588 basis points. During the Floating Rate Period, interest on this Security will be payable quarterly in arrears
on January 1, April 1, July 1 and October 1 of each year (each such date, a “Floating Rate Interest
Payment Date”, and together with a Fixed Rate Interest Payment Date, an “Interest Payment Date”),
with the first such Floating Rate Interest Payment Date being October 1, 2025, and the last such Floating Rate Interest Payment
Date being the Stated Maturity Date or any earlier redemption date. Notwithstanding the foregoing, if the Benchmark is less than
zero, the Benchmark shall be deemed to be zero. Interest on each Fixed Rate Interest Payment Date is payable to holders of record
on the Fixed Rate Regular Record Date pursuant to the Indenture. Interest on each Floating Rate Interest Payment Date is payable
to holders of record on the Floating Rate Regular Record Date pursuant to the Indenture.


 


The interest payable
on any Fixed Rate Interest Payment Date during the Fixed Rate Period will be computed on the basis of a 360-day year consisting
of twelve 30-day months to, but excluding, July 1, 2025. The interest payable on any Floating Rate Interest Payment Date during
the Floating Rate Period will be computed on the basis of a 360-day year and the number of days actually elapsed. If a Fixed Rate
Interest Payment Date or the Stated Maturity Date for this Security falls on a day that is not a Business Day, the interest payable
on such Interest Payment Date or the payment of principal and interest on the Stated Maturity Date will be paid on the next succeeding
Business Day, but the payments made on such dates will be treated as being made on the date that the payment was first due and
the Holder of this Security will not be entitled to any further interest or other payment. If a Floating Rate Interest Payment
Date falls on a day that is not a Business Day, then such Floating Rate Interest Payment Date will be postponed to the next succeeding
Business Day, unless such day falls in the next succeeding calendar month, in which case such Floating Rate Interest Payment Date
will be accelerated to the immediately preceding Business Day, and, in each such case, the amounts payable on such Business Day
will include interest accrued to, but excluding, such Business Day.


 






    	 	Exhibit A – Page 2	 



     


    

 


No sinking fund will
be provided with respect to this Security. In no event shall any Holder of this Security have the right to require the Company
to call, redeem or repurchase this Security, in whole or in part prior to maturity. Nothing in this paragraph, however, shall limit
the ability of the Holder of this Security to enforce its rights to the payment of principal and Additional Amounts, if any, and
interest on the Security at maturity as provided herein.





 


Payment of the principal
of and interest on this Security will be made in immediately available funds in U.S. dollars at the Corporate Trust Office of the
Trustee or other Paying Agent, or, at the option of the Company in the event this Security is no longer represented by a global
Security registered in the name of the Depository or its nominee, by check mailed to Holders of registered securities entitled
thereto as such Holders shall appear in the securities register.


 


Under certain conditions,
the Company may, without notice to or the consent of the Holder of this Security, create and issue additional notes ranking equally
with this Security and otherwise the same in all respects (except for the issue date, issue price, initial interest accrual date
and first Interest Payment Date), provided that no such additional notes may be issued unless (1) the additional notes
are fungible with this Security for United States securities law purposes, (2) (a) the additional notes are issued pursuant
to a “qualified reopening” of this Security for United States federal income tax purposes, or (b) this Security
was, and the additional notes are, issued without any original issue discount for United States federal income tax purposes and
(3) the additional notes have the same CUSIP number as this Security. No additional notes may be issued if any Default has
occurred and is continuing with respect to this Security. Such additional notes shall be consolidated and form a single series
with this Security.


 


The Securities shall
be issued as registered securities in the form of one or more permanent global Securities, without coupons, registered in the name
of the Depository or its nominee. The global Securities described above may be transferred by the Depository, in whole but not
in part, only to a nominee of the Depository, or by a nominee of the Depository to the Depository, or to a successor Depository
or to a nominee of such successor Depository.


 


Owners of beneficial
interests in such global Securities will not be considered the Holders thereof for any purpose hereunder. The rights of owners
of beneficial interests in such global Securities shall be exercised only through the Depository.


 


Any “depository
institution,” as defined in Section 3(c)(1) of the Federal Deposit Insurance Act, which holds a Security (or beneficial
interest therein) shall be deemed to have agreed by acquiring such Security (or beneficial interest) to waive any rights to offset
all or any portion of the indebtedness represented by such Security (or interest) against any indebtedness or other obligations
of such institution to the Company.


 


Reference is hereby
made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.


 


Unless the certificate
of authentication hereon has been executed by the Trustee by the manual signature of an authorized signatory, this Security shall
not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.


 






    	 	Exhibit A – Page 3	 



     


    

 


(Remainder of page intentionally left
blank)


 






    	 	Exhibit A – Page 4	 



     


    

 


IN WITNESS WHEREOF,
the Company has caused this instrument to be duly executed by manual or facsimile signature.


 


	 	BYLINE BANCORP, INC.
	 	 
	 	 
	 	By:	 
	 	Name:
	 	Title:
	 	 
	Dated:  June 26, 2020	 





 


TRUSTEE’S
CERTIFICATE OF AUTHENTICATION


 


This is one of the
Securities of the series designated therein referred to in the within-mentioned Indenture.


 


	 	U.S. BANK NATIONAL ASSOCIATION, as Trustee  
	 	 
	 	 
	 	By:	 
	 	 	Authorized Signatory
	 	 	 
	Dated:  June 26, 2020	 



 






    	 	Exhibit A – Page 5	 



     


    

 


REVERSE
OF SECURITY


 


This Security is one
of a duly authorized issue of 6.000% Fixed-to-Floating Rate Subordinated Notes due 2030 of the Company (the “Securities”),
issued and to be issued in one or more series under a Subordinated Debt Indenture, dated as of June 26, 2020 (the “Base
Indenture”), as supplemented by that First Supplemental Indenture, dated June 26 2020 (the “First Supplemental
Indenture,” and together with the Base Indenture, the “Indenture”), by and between the Company and
U.S. Bank National Association, as Trustee (herein called the “Trustee”, which term includes any successor trustee
under the Indenture), to which the Indenture and all indentures supplemental thereto reference is hereby made for a statement of
the respective rights, limitations of rights, duties and immunities thereunder of the Trustee, the Company and the Holders of the
Securities, and to which Indenture reference is hereby made for a statement of the terms upon which the Securities of this series
are, and are to be, authenticated and delivered. By the terms of the Indenture, the Securities are issuable in series that may
vary as to amount, date of maturity, rate of interest, rank and in any other respect provided in the Indenture.


 


The Company’s
indebtedness evidenced by this Security is, to the extent provided in the Indenture, subordinate and subject in right of payment
to the prior payment in full of all Senior Indebtedness, and this Security is issued subject to the provisions of the Indenture
with respect thereto. Each Holder of this Security, by accepting the same, (a) agrees to and shall be bound by such provisions,
(b) authorizes and directs the Trustee on his, her or its behalf to take such actions as may be necessary or appropriate to
effectuate the subordination so provided and (c) appoints the Trustee his, her or its attorney-in-fact for any and all such
purposes. Each Holder hereof, by his, her or its acceptance hereof, waives all notice of the acceptance of the subordination provisions
contained herein and in the Indenture by each holder of Senior Indebtedness, whether now outstanding or hereafter created, incurred,
assumed or guaranteed, and waives reliance by each such holder upon said provisions.


 


The Indenture contains
provisions for defeasance of this Security upon compliance with certain conditions set forth in the Indenture.


 


If certain Events of
Default with respect to Securities of this series shall occur, the principal of the Securities of this series will automatically,
and without any declaration or other action on the part of the Trustee or any Holder, become immediately due and payable in the
manner and with the effect provided in the Indenture. Certain defaults with respect to this Security may be waived by the Holder
hereof, as and if provided in the Indenture. The Company waives demand, presentment for prepayment, notice of nonpayment, notice
of protest and all other notices to the extent it may lawfully do so.


 


The Company may, at
its option, redeem the Securities, in whole or in part, at a redemption price equal to 100% of the principal amount of the Securities
to be redeemed plus accrued and unpaid interest to, but excluding, the date of redemption (the “Redemption Date”),
on any Interest Payment Date on or after July 1, 2025. The Company may also, at its option, redeem the Securities before the
Stated Maturity Date, in whole, but not in part, at any time, upon the occurrence of a Tier 2 Capital Event, a Tax Event or if
the Company is required to register as an investment company pursuant to the Investment Company Act of 1940, as amended. Any such
redemption will be at a redemption price equal to 100% of the principal amount of the Securities to be redeemed plus accrued and
unpaid interest to, but excluding, the Redemption Date fixed by the Company.


 






     

     


    

 


Notwithstanding any
of the foregoing, to the extent then required under or pursuant to applicable regulations of the Federal Reserve, this Security
may not be repaid prior to the Stated Maturity Date without the prior written consent of the Federal Reserve. In the event of redemption
of this Security in part only, a new Security or Securities of this series and of like tenor for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation hereof. The provisions of Article Eleven of the Base
Indenture and Section 2.8 of the First Supplemental Indenture shall apply to the redemption of any Securities by the Company.


 


In the event that any
payment on the Securities is subject to withholding of any U.S. federal income tax or other tax or assessment (as a result of a
change in law or otherwise), the Company will not pay Additional Amounts with respect to such tax or assessment.


 


No reference herein
to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of, premium and Additional Amounts (if any) and interest on this Security at
the times, place and rate, and in the coin or currency, herein prescribed.


 


As provided in the
Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security Register,
upon surrender of this Security for registration of transfer at the office or agency of the Company maintained under Section 1002
of the Base Indenture for such purpose, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory
to the Company and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon
one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount,
will be issued to the designated transferee or transferees. No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection
therewith.


 


Prior to due presentment
of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue,
and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary.


 


All terms used in this
Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.


 


Nothing in this Security,
express or implied, shall give to any person, other than the Holders of the Securities, the parties hereto and their permitted
successors hereunder, any benefit of any legal or equitable right, remedy or claim hereunder.


 


The Securities of this
series are issuable only in registered form without coupons in denominations of $1,000 and any integral multiples of $1,000 in
excess thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are
exchangeable for a like aggregate principal amount of Securities of such series of a different authorized denomination, as requested
by the Holder surrendering the same.


 






    	 	2	 



     


    

 


All notices under this
Security shall be in writing and in the case of the Company, addressed to the Company at 180 North LaSalle Street, Suite 300,
Chicago, Illinois 60601, Attention: Chief Financial Officer, or, in the case of the Trustee, at the Corporate Trust Office
at 190 South LaSalle Street, Chicago, Illinois 60603, Attention: Corporate Trust and Agency Group, or to such other address
of the Trustee as the Trustee may notify the holders of the Securities. All notices to the Holder of this Security will be given
to the Holder at its address as it appears in the security register.


 


All covenants and agreements
by the Company in this Security and the Indenture shall bind the Company’s successors and assigns, including successors by
operation of law resulting from a merger or consolidation of the Company, or successors resulting from the transfer of the Company’s
assets and liabilities substantially or entirely, to another entity (“Successors”). Any Successor shall expressly
assume in writing all the Company’s obligations hereunder prior to becoming a Successor, and upon becoming a Successor, shall
perform all the Company’s obligations hereunder and make all payments due hereunder.


 


In case any provision
in this Security shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions
shall not in any way be affected or impaired thereby.


 


EACH OF THE COMPANY,
THE TRUSTEE AND EACH HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF, HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED
BY APPLICABLE LAW, ANY AND ALL RIGHT IT MAY HAVE TO TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT
OF OR RELATING TO THIS SECURITY, THE INDENTURE, OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY.


 


This Security shall
be governed by and construed in accordance with the laws of the State of New York and, where applicable, the federal laws of the
United States of America.


 






    	 	3	 



     


    

 


[FORM OF TRANSFER NOTICE]


 


To assign this Security, fill in the form
below:


 


	(I) or (we) assign and transfer this Note to:	 
	 	(Insert Assignee’s legal name)



 


 


(Insert assignee’s Soc. Sec. or tax
I.D. no.)

(Print or type assignee’s name, address and zip code)


and irrevocably appoint to transfer this
Security on the books of the Company. The agent may substitute another to act for him.


 


	Date:	 	 



 


	Your signature:	
	 	(Sign exactly as your name appears on| the face
of this Security)
	 	 
	Signature Guarantee*:	 


 


*Participant in a recognized Signature
Guarantee Medallion Program (or other signature guarantor acceptable to the Trustee).