Duolingo holder plans $5.0M Rule 144 share sale

Luis von Ahn Foundation filed to sell 34,992 Duolingo (DUOL) common shares under Rule 144, with an indicated value of about $5 million.

Rhea-AI Filing Summary

Duolingo, Inc. (DUOL) is the issuer for a proposed Rule 144 sale by the Luis von Ahn Foundation. The filing covers the planned sale of 34,992 shares of Duolingo common stock, with an aggregate market value of $4,965,364.80, against 40,387,012 shares outstanding as of the notice.

The shares are held at Morgan Stanley Smith Barney LLC Executive Financial Services and are identified as founders shares originally acquired from the issuer on August 25, 2011. The approximate sale date stated is September 21, 2026. Recent Rule 10b5-1 plan sales over the prior three months are also disclosed for both Luis von Ahn Arellano and the foundation.

Key Figures

Shares to be sold: 34,992 shares Aggregate market value of shares to be sold: $4,965,364.80 Shares outstanding: 40,387,012 shares +4 more

7 metrics

Shares to be sold 34,992 shares Planned Rule 144 sale by Luis von Ahn Foundation

Aggregate market value of shares to be sold $4,965,364.80 Value of 34,992 Duolingo common shares covered by the notice

Shares outstanding 40,387,012 shares Duolingo common stock outstanding as referenced in the notice

Recent 10b5-1 sale by Luis von Ahn Arellano 28,292 shares for $4,250,140.24 Sale dated September 16, 2026

Recent 10b5-1 sale by Luis von Ahn Foundation 19,008 shares for $2,832,624.09 Sale dated September 16, 2026

Approximate date of sale September 21, 2026 Planned Rule 144 transaction date

Original acquisition date of founders shares August 25, 2011 Acquisition of the Duolingo shares by the foundation from the issuer

Key Terms

Rule 144, 10b5-1, Founders Shares, Aggregate Market Value, +1 more

5 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

10b5-1 regulatory

"10b5-1 Sales for LUIS VON AHN ARELLANO"

A 10b5-1 plan is a pre-set schedule that lets company insiders buy or sell shares according to written instructions made when they do not possess material, nonpublic information. Think of it as a timed automatic payment for stock trades: it helps insiders avoid accusations of trading on secret information and gives outside investors a clearer signal about whether sales are routine or potentially informative about the company’s prospects.

Founders Shares financial

"Founders Shares | Issuer | | | 34992 | 08/25/2011"

Founders shares are a special block of a company’s stock originally given to the people who started the business; they often carry extra voting power or favorable terms compared with regular shares. For investors, these shares matter because they concentrate control and influence how future funding, ownership dilution, and decision-making will play out—think of founders shares as the steering wheel that can steer a company’s direction even as more passengers (investors) climb aboard.

Aggregate Market Value financial

"Common | ... | 34992 | 4965364.80 | 40387012 | 09/21/2026"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

Morgan Stanley Smith Barney LLC Executive Financial Services financial

"Common | Morgan Stanley Smith Barney LLC Executive Financial Services"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the Form 144 filing disclose for Duolingo (DUOL)?

It discloses that the Luis von Ahn Foundation plans to sell 34,992 shares of Duolingo common stock under Rule 144, with an aggregate market value of $4,965,364.80 and an approximate sale date of September 21, 2026.

How many Duolingo (DUOL) shares does the Luis von Ahn Foundation plan to sell?

The Luis von Ahn Foundation plans to sell 34,992 shares of Duolingo common stock. These are described as founders shares originally acquired from Duolingo on August 25, 2011.

What is the indicated value of the Duolingo (DUOL) shares to be sold?

The filing lists an aggregate market value of $4,965,364.80 for the 34,992 Duolingo shares covered by the planned Rule 144 sale by the Luis von Ahn Foundation.

How many Duolingo (DUOL) shares are shown as outstanding in this notice?

The notice reports 40,387,012 shares of Duolingo common stock outstanding. This figure serves as context for the planned Rule 144 sale and is not the amount being sold.

What recent Rule 10b5-1 plan sales related to Duolingo (DUOL) are disclosed?

The filing lists 10b5-1 sales on September 16, 2026 of 28,292 shares for $4,250,140.24 for Luis von Ahn Arellano and 19,008 shares for $2,832,624.09 for the Luis von Ahn Foundation.

Through which broker are the Duolingo (DUOL) shares held for this planned sale?

The Duolingo shares for the planned Rule 144 sale are held at Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/21/2026 - 04:33 PM Accepted by SEC EDGAR 09/21/2026 - 04:32 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001966358
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Duolingo, Inc.
SEC File Number	001-40653
Address of Issuer	5900 Penn Avenue Pittsburgh PENNSYLVANIA 15206
Phone	4125676602
Name of Person for Whose Account the Securities are To Be Sold	LUIS VON AHN FOUNDATION
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director
Relationship to Issuer	Officer
Relationship to Issuer	10% Stockholder

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	34992	4965364.80	40387012	09/21/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/25/2011	Founders Shares	Issuer			34992	08/25/2011	N/A

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
10b5-1 Sales for LUIS VON AHN ARELLANO 5900 Penn Avenue Pittsburgh PA 15206	Common	09/16/2026	28292	4250140.24
10b5-1 Sales for LUIS VON AHN FOUNDATION 5900 Penn Avenue Pittsburgh PA 15206	Common	09/16/2026	19008	2832624.09

144: Remarks and Signature

Remarks
Date of Notice	09/21/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/02/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Luis von Ahn Arellano
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)