Key facts
- This page summarizes Severin Hacker's Form 4 filing for Duolingo, Inc. (DUOL).
- 22 reported transactions and 7 derivative rows are listed below.
- Accepted by SEC: 22 Oct 2025, 20:16.
Severin Hacker - 20 Oct 2025 Form 4 Insider Report for Duolingo, Inc. (DUOL)
- Reporting relationship
- Chief Tech Officer, Co-Founder, Director, 10%+ Owner
- Issuer ticker
- DUOL
- Reported as of
- 20 Oct 2025
- Net transaction value
- -$12,701,830
- SEC form
- 4
- Accepted by SEC
- 22 Oct 2025, 20:16:42 UTC
- Prior SEC filing
- 07 Oct 2025
- Next SEC filing
- 06 Nov 2025
- Source filing
- View source filing
- Reporting owner signature
- /s/ Stephen Chen, as Attorney-in-Fact for Severin Hacker
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
Severin Hacker filed Form 4 for Duolingo, Inc. (DUOL) on 22 Oct 2025.
Change
- Previous filing in this sequence was filed on 07 Oct 2025.
- Current net transaction value: -$12,701,830.
Research use
- This tells you what this filing adds before you inspect full transaction and derivative tables.
- You can trace every row back to the original SEC filing document.
Evidence
Filed on Form 4
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (1)
CIK 0001870272
Primary reporting owner
Hacker Severin
- Relationship
- Chief Tech Officer, Co-Founder, Director, 10%+ Owner
- Address
- C/O DUOLINGO, INC., 5900 PENN AVENUE, PITTSBURGH
- Signature
- /s/ Stephen Chen, as Attorney-in-Fact for Severin Hacker
- Signature date
- 22 Oct 2025
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
DUOL
transaction
Class A Common Stock
Conversion of derivative security
- Transaction value
- $380,800
- Shares
- +10,000
- Change %
- +13889%
- Price
- $38.08
- Shares after
- 10,072
- Date
- 20 Oct 2025
- Ownership
- Direct
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $30,586
- Shares
- -100
- Change %
- -0.99%
- Price
- $305.86
- Shares after
- 9,972
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $184,532
- Shares
- -600
- Change %
- -6%
- Price
- $307.55
- Shares after
- 9,372
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F2
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $154,532
- Shares
- -500
- Change %
- -5.3%
- Price
- $309.06
- Shares after
- 8,872
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F3
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $195,882
- Shares
- -632
- Change %
- -7.1%
- Price
- $309.94
- Shares after
- 8,240
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F4
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $311,428
- Shares
- -1,000
- Change %
- -12%
- Price
- $311.43
- Shares after
- 7,240
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F5
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $400,152
- Shares
- -1,281
- Change %
- -18%
- Price
- $312.37
- Shares after
- 5,959
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F6
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $156,967
- Shares
- -500
- Change %
- -8.4%
- Price
- $313.93
- Shares after
- 5,459
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F7
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $347,365
- Shares
- -1,100
- Change %
- -20%
- Price
- $315.79
- Shares after
- 4,359
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F8
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $506,617
- Shares
- -1,600
- Change %
- -37%
- Price
- $316.64
- Shares after
- 2,759
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F9
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $216,025
- Shares
- -680
- Change %
- -25%
- Price
- $317.68
- Shares after
- 2,079
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F10
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $289,085
- Shares
- -907
- Change %
- -44%
- Price
- $318.73
- Shares after
- 1,172
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F11
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $95,991
- Shares
- -300
- Change %
- -26%
- Price
- $319.97
- Shares after
- 872
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F12
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $128,699
- Shares
- -400
- Change %
- -46%
- Price
- $321.75
- Shares after
- 472
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F13
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $96,927
- Shares
- -300
- Change %
- -64%
- Price
- $323.09
- Shares after
- 172
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1, F14
DUOL
transaction
Class A Common Stock
Sale
- Transaction value
- $32,410
- Shares
- -100
- Change %
- -58%
- Price
- $324.10
- Shares after
- 72
- Date
- 20 Oct 2025
- Ownership
- Direct
- Footnotes
- F1
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
DUOL
transaction
Derivative
Stock Option (Right to Buy)
Options Exercise
- Transaction value
- $0
- Shares
- -10,000
- Change %
- -28%
- Price
- $0.000000
- Shares after
- 25,252
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class B Common Stock
- Underlying amount
- 10,000
- Exercise price
- $38.08
- Footnotes
- F15
DUOL
transaction
Derivative
Class B Common Stock
Conversion of derivative security
- Transaction value
- $0
- Shares
- +10,000
- Change %
- +12%
- Price
- $0.000000
- Shares after
- 96,075
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 10,000
- Exercise price
- Footnotes
- F16
DUOL
transaction
Derivative
Class B Common Stock
Conversion of derivative security
- Transaction value
- $0
- Shares
- -10,000
- Change %
- -10%
- Price
- $0.000000
- Shares after
- 86,075
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 10,000
- Exercise price
- Footnotes
- F16
DUOL
transaction
Derivative
Performance-Based Restricted Stock Units
Options Exercise
- Transaction value
- $0
- Shares
- -60,000
- Change %
- -13%
- Price
- $0.000000
- Shares after
- 390,000
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class B Common Stock
- Underlying amount
- 60,000
- Exercise price
- Footnotes
- F17, F18
DUOL
transaction
Derivative
Class B Common Stock
Options Exercise
- Transaction value
- $0
- Shares
- +60,000
- Change %
- +70%
- Price
- $0.000000
- Shares after
- 146,075
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 60,000
- Exercise price
- Footnotes
- F16
DUOL
transaction
Derivative
Class B Common Stock
Tax liability
- Transaction value
- $9,935,432
- Shares
- -31,770
- Change %
- -22%
- Price
- $312.73
- Shares after
- 114,305
- Date
- 20 Oct 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 31,770
- Exercise price
- Footnotes
- F16
DUOL
holding
Derivative
Class B Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 2,886,917
- Date
- 20 Oct 2025
- Ownership
- See footnote
- Underlying class
- Class A Common Stock
- Underlying amount
- 2,886,917
- Exercise price
- Footnotes
- F16, F19
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Rule 10b5-1 trading plan
These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.
Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).
Explanation of responses 19 footnotes
Footnote F1
The sale was effected pursuant to the Reporting Person's Rule 10b5-1 trading plan adopted on September 11, 2024.
Footnote F2
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 $307.18 to $307.89, 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.
Footnote F3
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 $308.61 to $309.24, 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.
Footnote F4
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 $309.71 to $310.18, 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.
Footnote F5
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 $310.86 to $311.81, 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.
Footnote F6
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 $311.94 to $312.65, 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.
Footnote F7
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 $313.65 to $314.30, 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.
Footnote F8
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 $315.18 to $316.17, 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.
Footnote F9
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 $316.22 to $317.19, 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.
Footnote F10
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 $317.22 to $318.20, 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.
Footnote F11
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 $318.38 to $319.26, 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.
Footnote F12
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 $319.85 to $320.21, 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.
Footnote F13
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 $321.32 to $322.19, 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.
Footnote F14
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 $322.98 to $323.25, 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.
Footnote F15
The shares subject to the option are fully vested and exercisable.
Footnote F16
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.
Footnote F17
Each Performance-Based Restricted Stock Unit ("PSU") represents a contingent right to receive one share of the Issuer's Class B Common Stock upon vesting. The PSUs vest upon the satisfaction of both a service-based condition and a performance-based condition. The service-based condition is satisfied as to 25% of the PSUs on each anniversary of the completion of the Issuer's initial public offering of Class A common stock based on the Reporting Person's continuous service as CTO to the Issuer through the applicable vesting dates, subject to acceleration upon a cessation of service as CTO as a result of death or permanent disability.
Footnote F18
The performance-based condition will be satisfied upon the Issuer's Class A common stock achieving certain stock price hurdles over a period of ten years. Vested PSUs will be settled by the issuance of the underlying Class B Common Stock on the first anniversary of vesting, subject to acceleration upon a termination of employment or a change in control of the Issuer.
Footnote F19
Shares held by SBH Trust dated March 10, 2020, of which Reporting Person is Trustee.