Byline Bancorp (NYSE: BY) 10% holder sells 300,000 shares to issuer

Rhea-AI Filing Summary

MBG Investors I, L.P., a 10% owner of Byline Bancorp, Inc., reported a sale of 300,000 shares of common stock on August 7, 2026. The shares were sold to and repurchased by Byline Bancorp under a Stock Repurchase Agreement at $39.10 per share, a price based on the five-day average NYSE closing price from July 27–31, 2026. Following this transaction, MBG Investors I, L.P. directly holds 11,535,145 shares. Antonio del Valle Perochena, the general partner with a 16.68% partnership interest, has sole voting and investment power but disclaims beneficial ownership except to the extent of his pecuniary interest.

Insider Trade Summary

Net Seller: 300,000 shares

Net Sell 1 txn

Insider MBG INVESTORS I, L.P.

Role 10% Owner

Sold 300,000 shs ($11.73M)

Type	Security	Shares	Price	Value
Sale	Common stock F1, F2	300,000	$39.10	$11.73M

Holdings After Transaction: Common stock — 11,535,145 shares (Direct)

Footnotes (2)

1. F1. Sale to and repurchase by Byline Bancorp, Inc. ("the Issuer") of 300,000 shares of Common Stock (the "Shares") pursuant to a Stock Repurchase Agreement (the "Stock Repurchase Agreement") dated as of August 7, 2026 between MBG Investors I, L.P. and the Issuer. Under the Stock Repurchase Agreement, the Issuer agreed to purchase the Shares at a price of $39.10 per Share, which price was determined based on the five (5) day average closing price for the Common Stock on the NYSE for the period from July 27, 2026 through July 31, 2026.
2. F2. Mr. Antonio del Valle Perochena is the general partner of MBG Investors I, L.P. and possesses sole voting and investment power with respect to the shares of common stock held by MBG Investors I, L.P. Mr. del Valle Perochena owns 16.68% of the partnership interests of MBG Investors I, L.P. Mr. del Valle Perochena disclaims beneficial ownership of such shares of common stock except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that he is the beneficial owner of such disclaimed shares of common stock for purposes of Section 16 or for any other purpose. The address for MBG Investors I, L.P. is 365 Bay Street, Suite 800, M5H2V1 Toronto, Ontario, Canada.

Key Figures

Shares sold: 300,000 shares Sale price per share: $39.10 per share Shares held after transaction: 11,535,145 shares +1 more

4 metrics

Shares sold 300,000 shares Common stock sold by MBG Investors I, L.P. on August 7, 2026

Sale price per share $39.10 per share Price under Stock Repurchase Agreement based on five-day NYSE average

Shares held after transaction 11,535,145 shares Direct ownership of Byline Bancorp common stock by MBG Investors I, L.P. after sale

General partner interest 16.68% Partnership interest of Antonio del Valle Perochena in MBG Investors I, L.P.

Key Terms

Stock Repurchase Agreement, five (5) day average closing price, beneficial ownership, pecuniary interest

4 terms

Stock Repurchase Agreement financial

"pursuant to a Stock Repurchase Agreement (the "Stock Repurchase Agreement") dated as of August 7, 2026"

five (5) day average closing price financial

"price was determined based on the five (5) day average closing price for the Common Stock"

beneficial ownership regulatory

"disclaims beneficial ownership of such shares of common stock except to the extent of his pecuniary interest"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission"

FAQ

What insider transaction did BY (Byline Bancorp, Inc.) report from MBG Investors I, L.P.?

Byline Bancorp, Inc. reported that MBG Investors I, L.P. sold 300,000 shares of its common stock on August 7, 2026. The shares were repurchased by Byline Bancorp under a Stock Repurchase Agreement at a set price per share.

At what price were the 300,000 BY shares sold by MBG Investors I, L.P.?

The 300,000 Byline Bancorp (BY) shares were sold at $39.10 per share. This price was determined using the five-day average closing price of the common stock on the NYSE from July 27–31, 2026 under the repurchase agreement.

How many BY shares does MBG Investors I, L.P. hold after the reported sale?

After the transaction, MBG Investors I, L.P. holds 11,535,145 shares of Byline Bancorp common stock. This figure reflects its direct ownership position immediately following the 300,000-share sale back to the company.

What agreement governed the BY share repurchase from MBG Investors I, L.P.?

The transaction was carried out under a Stock Repurchase Agreement dated August 7, 2026 between Byline Bancorp, Inc. and MBG Investors I, L.P. The agreement set the $39.10 per share price based on a prior five-day NYSE average.

Who controls voting and investment power over MBG Investors I, L.P.’s BY shares?

Mr. Antonio del Valle Perochena, the general partner of MBG Investors I, L.P., has sole voting and investment power over the Byline Bancorp shares. He owns 16.68% of the partnership interests and disclaims beneficial ownership beyond his pecuniary interest.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/11/2026 - 05:57 PM Accepted by SEC EDGAR 08/11/2026 - 05:57 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

MBG INVESTORS I, L.P.

(Last) (First) (Middle)

180 NORTH LASALLE STREET

SUITE 300

(Street)

CHICAGO ILLINOIS 60601

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
BYLINE BANCORP, INC. [ BY ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/07/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common stock	08/07/2026		S		300,000(1)	D	$39.1	11,535,145	D(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Sale to and repurchase by Byline Bancorp, Inc. ("the Issuer") of 300,000 shares of Common Stock (the "Shares") pursuant to a Stock Repurchase Agreement (the "Stock Repurchase Agreement") dated as of August 7, 2026 between MBG Investors I, L.P. and the Issuer. Under the Stock Repurchase Agreement, the Issuer agreed to purchase the Shares at a price of $39.10 per Share, which price was determined based on the five (5) day average closing price for the Common Stock on the NYSE for the period from July 27, 2026 through July 31, 2026.

2. Mr. Antonio del Valle Perochena is the general partner of MBG Investors I, L.P. and possesses sole voting and investment power with respect to the shares of common stock held by MBG Investors I, L.P. Mr. del Valle Perochena owns 16.68% of the partnership interests of MBG Investors I, L.P. Mr. del Valle Perochena disclaims beneficial ownership of such shares of common stock except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that he is the beneficial owner of such disclaimed shares of common stock for purposes of Section 16 or for any other purpose. The address for MBG Investors I, L.P. is 365 Bay Street, Suite 800, M5H2V1 Toronto, Ontario, Canada.

	/s/ Alberto J. Paracchini, Attorney-in-Fact	08/11/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)