DUOL Form 4: Co-founder sells shares under 10b5-1 plan, large trust holding remains

Rhea-AI Filing Summary

Severin Hacker, Co-Founder and Chief Tech Officer of Duolingo (DUOL), reported multiple transactions on 08/19/2025. He acquired a stock option for 10,000 shares with a $38.08 exercise price and exercised or acquired 10,000 shares of Class B common stock. Simultaneously he sold a series of Class A shares under a Rule 10b5-1 trading plan, disposing of 10,000 then multiple blocks totaling 8,928 shares at weighted-average prices ranging roughly from $338.49 to $363.05. After these transactions he directly owns 72 Class A shares and indirectly holds 2,896,917 Class A shares through the SBH Trust, where he is trustee.

Positive

• Retains a material indirect stake of 2,896,917 Class A shares via SBH Trust, indicating continued substantial economic interest.
• Option activity recorded: acquisition/exercise of a 10,000-share option at a $38.08 exercise price (fully vested).
• Sales executed under a documented 10b5-1 trading plan adopted September 11, 2024, showing preplanned compliance with insider trading rules.

Negative

• Significant insider sales of Class A shares totaling 18,928 shares reported on 08/19/2025, which reduced direct holdings to 72 shares.
• Concentration of direct ownership reduced to a nominal direct stake, shifting voting/economic interest to an indirect trust position.

Insights

Securities Analyst

TL;DR: Significant scheduled insider selling occurred alongside option activity, while a large indirect stake remains concentrated in a trust.

The reported sales were executed pursuant to a 10b5-1 plan dated September 11, 2024, indicating preplanned dispositions rather than ad hoc sales. The filing shows a 10,000-share option transaction with a $38.08 strike and multiple weighted-average sales of Class A shares at prices roughly between $338 and $363. Post-transaction direct ownership is minimal (72 shares) while indirect ownership via SBH Trust remains 2,896,917 shares, reflecting continued material economic interest and control. For investors, the mix of option exercise/acquisition, systematic sales under a plan, and retained indirect holdings are the key takeaways.

Corporate Governance Expert

TL;DR: Director/officer followed a Rule 10b5-1 plan; ownership structure still concentrated in trust control.

The Form 4 documents compliant use of a 10b5-1 trading plan for multiple sales and records an option-related acquisition and Class B to Class A share reporting. The disclosure that Class B shares convert to Class A and that shares are held in SBH Trust (with Hacker as trustee) underscores governance continuity and ongoing indirect control despite significant sales. The filing is detailed on sale price ranges and offers transparency on execution through weighted-average prices and broker reporting commitments.

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).

X

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^*

Hacker Severin

(Last) (First) (Middle)

C/O DUOLINGO, INC.

5900 PENN AVENUE

(Street)

PITTSBURGH PA 15206

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Duolingo, Inc. [ DUOL ]

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

X	Director	X	10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Tech Officer, Co-Founder

3. Date of Earliest Transaction (Month/Day/Year)
08/19/2025

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

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

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

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
Class A Common Stock	08/19/2025		C		10,000	A	$38.08	10,072	D
Class A Common Stock	08/19/2025		S(1)		1,003	D	$339.148(2)	9,069	D
Class A Common Stock	08/19/2025		S(1)		1,700	D	$340.0274(3)	7,369	D
Class A Common Stock	08/19/2025		S(1)		1,979	D	$340.9173(4)	5,390	D
Class A Common Stock	08/19/2025		S(1)		1,318	D	$341.9974(5)	4,072	D
Class A Common Stock	08/19/2025		S(1)		300	D	$343.82(6)	3,772	D
Class A Common Stock	08/19/2025		S(1)		300	D	$345.02(7)	3,472	D
Class A Common Stock	08/19/2025		S(1)		600	D	$346.145(8)	2,872	D
Class A Common Stock	08/19/2025		S(1)		500	D	$347.4803(9)	2,372	D
Class A Common Stock	08/19/2025		S(1)		400	D	$348.825(10)	1,972	D
Class A Common Stock	08/19/2025		S(1)		100	D	$349.28	1,872	D
Class A Common Stock	08/19/2025		S(1)		400	D	$351.29(11)	1,472	D
Class A Common Stock	08/19/2025		S(1)		200	D	$352.4(12)	1,272	D
Class A Common Stock	08/19/2025		S(1)		300	D	$354.0767(13)	972	D
Class A Common Stock	08/19/2025		S(1)		400	D	$354.885(14)	572	D
Class A Common Stock	08/19/2025		S(1)		100	D	$357.67	472	D
Class A Common Stock	08/19/2025		S(1)		200	D	$359.3(15)	272	D
Class A Common Stock	08/19/2025		S(1)		200	D	$363.05	72	D

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
Stock Option (Right to Buy)	$38.08	08/19/2025		M			10,000	(16)	12/02/2030	Class B Common Stock	10,000	$0	65,252	D
Class B Common Stock	(17)	08/19/2025		C		10,000		(17)	(17)	Class A Common Stock	10,000	$0	96,075	D
Class B Common Stock	(17)	08/19/2025		C			10,000	(17)	(17)	Class A Common Stock	10,000	$0	86,075	D
Class B Common Stock	(17)							(17)	(17)	Class A Common Stock	2,896,917		2,896,917	I	See footnote(18)

Explanation of Responses:

1. The sale was effected pursuant to the Reporting Person's Rule 10b5-1 trading plan adopted on September 11, 2024.

2. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $338.49 to $339.44, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

3. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $339.49 to $340.46, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

4. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $340.50 to $341.37, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

5. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $341.59 to $342.42, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

6. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $343.19 to $344.16, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

7. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $344.68 to $345.19, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

8. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $345.85 to $346.53, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

9. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $347.07 to $347.91, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

10. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from 348.22 to $349.21, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

11. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $351.04 to $351.48, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

12. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $352.20 to $352.60, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

13. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $353.61 to $354.52, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

14. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $354.66 to $355.42, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

15. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $358.83 to $359.77, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

16. The shares subject to the option are fully vested and exercisable.

17. Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock in connection with: (i) any transfer, whether or not for value, except for certain permitted transfers further described in the Issuer's amended and restated certificate of incorporation, (ii) such time as the aggregate number of shares of Class B Common Stock outstanding ceases to represent 5% of the aggregate number of shares of Common Stock outstanding, and (iii) the death of the Reporting Person.

18. Shares held by SBH Trust dated March 10, 2020, of which Reporting Person is Trustee.

Remarks:

	/s/ Stephen Chen, as Attorney-in-Fact for Severin Hacker	08/21/2025
	** 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.

FAQ

What insider activity did Severin Hacker report for DUOL on 08/19/2025?

He acquired or exercised a 10,000-share option at $38.08 and sold multiple blocks of Class A shares totaling 18,928 shares under a 10b5-1 plan.

Were the sales by Severin Hacker part of a trading plan?

Yes. The filing states the sales were effected pursuant to a Rule 10b5-1 trading plan adopted on September 11, 2024.

How many DUOL shares does Hacker beneficially own after these transactions?

Directly owns 72 Class A shares and indirectly holds 2,896,917 Class A shares via the SBH Trust.

At what prices were the Class A shares sold?

Sales were executed at weighted-average prices with reported ranges approximately from $338.49 up to $363.05 across multiple blocks.

Does the filing indicate whether Class B shares convert to Class A?

Yes. Each Class B share is convertible into one Class A share under the company's charter and certain events trigger automatic conversion.