Duolingo, Inc. (DUOL): A Bull Case Theory 

We came across a bullish thesis on Duolingo, Inc. on Investment Ideas by Antonio’s Substack by Antonio Linares. In this article, we will summarize the bulls’ thesis on DUOL. Duolingo, Inc.’s share was trading at $142.80 as of January 28th. DUOL’s trailing and forward P/E were 18.40 and 25.51 respectively according to Yahoo Finance.

Duolingo, Inc. operates as a mobile learning platform in the United States, the United Kingdom, and internationally. Duolingo is entering what can be described as a fortune-making phase, as the market is misinterpreting a natural deceleration in daily active user growth as competitive pressure from ChatGPT rather than a deliberate strategic shift. In reality, Duolingo is an AI-native company, and management has explicitly stated that platform retention remains strong, with no meaningful changes observed. Historically, Duolingo’s growth has never been linear.

When DAU growth stalled in the past, the company successfully reaccelerated by identifying and optimizing a single metric that disproportionately drove user lifetime value, reinforcing its ability to cycle between growth phases while preserving long-term value creation. This operating discipline remains intact today, even as the company serves just over 50 million DAUs within what management views as a multi-trillion-dollar global education opportunity, positioning Duolingo as a potential operating system for learning.

Duolingo continuously balances monetization, user growth, and teaching quality, dynamically prioritizing one lever without sacrificing the others. This approach is evident in its fluctuating but steadily rising free cash flow margins, alongside strong revenue and operating cash flow growth, underscoring exceptional execution.

Management has now signaled a renewed emphasis on improving learning outcomes, confident that better teaching ultimately translates into sustained user growth, as it has historically. Importantly, this strategic focus does not compromise financial performance, with adjusted EBITDA margins tracking close to long-term targets even as the company continues to invest in innovation.

New product features, such as Energy, are already demonstrating the effectiveness of this strategy by simultaneously boosting bookings and DAUs. Critically, Duolingo’s value creation is driven by rapid iteration, a process meaningfully accelerated by AI, enabling faster improvement in learning outcomes at lower cost. As teaching effectiveness compounds, free cash flow per share is poised to accelerate materially. Given that long-term stock prices ultimately follow free cash flow, Duolingo appears materially undervalued, offering investors an opportunity to own an extraordinary business at a moment of widespread misperception.

Previously, we covered a bullish thesis on Duolingo, Inc. (DUOL) by Lorenzo Bastianelli in May 2025, which highlighted viral marketing-led user growth, rising engagement, and expanding AI-driven course offerings. DUOL’s stock price has depreciated by approximately 71.62% since our coverage due to valuation compression and DAU growth concerns. Antonio Linares shares a similar thesis but emphasizes long-term free cash flow acceleration driven by AI-led iteration and teaching quality.

Duolingo, Inc. is not on our list of the 30 Most Popular Stocks Among Hedge Funds. As per our database, 50 hedge fund portfolios held DUOL at the end of the third quarter which was 55 in the previous quarter. While we acknowledge the risk and potential of DUOL as an investment, our conviction lies in the belief that some AI stocks hold greater promise for delivering higher returns and doing so within a shorter time frame. If you are looking for an AI stock that is more promising than DUOL and that has 10,000% upside potential, check out our report about this cheapest AI stock.

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Disclosure: None.