Duolingo Faces Securities Class Action Over Monetization and Growth Claims

What the lawsuit says

The case is captioned City of Dearborn Heights Act 345 Police & Fire Retirement System v. Duolingo, Inc., No. 2:26-cv-02197, and was filed in the United States District Court for the Western District of Pennsylvania. It covers those who purchased or acquired Duolingo Class A common stock during the class period, inclusive of both dates.

According to the complaint as summarized by Kessler Topaz, the defendants made materially false or misleading statements and failed to disclose material facts about the company's business, operations and prospects. Kessler Topaz notes that it did not file the complaint itself.

The allegations center on four points:

• Daily active user (DAU) growth rates were allegedly being leveraged against deliberately added user friction, including significant increases in ad volume, subscription tier upsells and worsened product quality. The complaint says Duolingo understood that any amount of friction would cause users to leave.
• Duolingo's A/B testing allegedly showed the company that increased friction in the free experience, including its monetization push and rapidly generated low-quality AI content, was hurting DAU growth.
• Quickly generated AI content was allegedly worsening product quality and threatening the sustainability of financial performance.
• As a result, the defendants' statements allegedly were materially false and misleading or lacked a reasonable basis.

The stock drops cited

The notice ties the allegations to three events. On November 5, 2025, Duolingo reported third quarter results showing DAU growth of 36%, down from 49% in the first quarter. The company also said it would reverse course on its monetization push and focus on user growth. The stock fell 25% to close at $193.74 on November 6, 2025.

On January 12, 2026, Duolingo announced that its CFO had resigned and gave limited preliminary fourth quarter metrics showing DAU growth of only 30%. The stock fell another 8.5% to close at $161.74 that day.

After the market closed on February 26, 2026, Duolingo reported fourth quarter results. According to the notice, the company revealed that 2026 DAU growth would come in at 20%, accompanied by lower bookings and less profitability. The notice says this showed the "small financial impact" from the strategic shift was anything but. The stock fell 14% to close at $101 on February 27, 2026.

Lead plaintiff process and deadline

Investors who want to lead the case have until December 7, 2026, to seek appointment as lead plaintiff. They can do so through Kessler Topaz or other counsel, or they can take no action and remain an absent class member.

The notice describes a lead plaintiff as a representative who directs the litigation on behalf of all class members. It is usually the investor or small group with the largest financial interest who is also adequate and typical of the proposed class. The lead plaintiff selects counsel, which becomes lead or class counsel if approved by the court. According to the firm, the ability to share in any recovery does not depend on whether an investor serves as lead plaintiff.

Kessler Topaz says representation is on a contingency fee basis, with no cost to investors, and that speaking with an attorney carries no obligation.

What it means for investors

The claims are allegations in a complaint, and the notice does not report any court finding. For investors who held Duolingo Class A shares during the class period and lost money, the December 7, 2026 date is the key deadline for seeking a lead role. The notice is also attorney advertising from a firm that seeks to represent investors in the case, so its framing reflects the plaintiff-side view.