AI Impact on Y Combinator Applications: A Closer Look
Y Combinator (YC), the renowned startup accelerator behind the success of companies such as Reddit, DoorDash, and Airbnb, has observed a significant shift in the way founders submit their applications. Since its inception, YC has invested in over 5,000 startups, supporting early-stage companies through rigorous selection processes. Recently, YC leaders have noted that many founders appear to be relying increasingly on AI-generated content to craft their application responses.
The application process requires founders to articulate their idea selection rationale, identify competitors, and outline revenue strategies. However, subtle indicators suggest a growing dependency on artificial intelligence to write these answers. This trend reflects a broader adoption of AI tools in startup ecosystems, raising important questions about authenticity and originality in founder narratives.
Longer Responses and AI Writing Signatures
One of the most notable signs of AI involvement is the noticeable increase in application length. According to YC partner Tyler Bosmeny, the average length of YC applications has surged by 60% over the past three years. “I wonder what could explain that…” he remarked on X (formerly Twitter), underscoring the unusual growth in response size.
Another key marker identified by YC partner Pete Koomen is the frequent use of the word “wedge” and the increased presence of em dashes. Koomen, after spending a week reading applications, pointed out that “back in my day (one year ago) founders didn’t talk like this.” Data shared by Koomen illustrates that the usage of “wedge” in applications jumped from less than 1% in spring 2025 to over 20% in summer 2026. Likewise, em dashes—especially those with spaces around them—have become a common stylistic feature, rising steadily since 2023 and peaking in 2024, with more than 50% of applications including them by summer 2025.
These linguistic patterns coincide with the launch of advanced AI models such as Anthropic’s Opus 4, indicating that founders are increasingly leveraging AI tools to enhance or generate their written content.
The Changing Vocabulary of Founders
Interestingly, certain words have fallen out of favor even as others rise in usage. YC co-founder Paul Graham highlighted this phenomenon in an April 2024 X post. He recounted receiving a cold email containing the word “delve,” which Graham associates strongly with AI-generated text, specifically from ChatGPT. “My point here is not that I dislike ‘delve,’ though I do, but that it’s a sign that text was written by ChatGPT,” he explained.
Supporting this observation, researcher Philip Shapira’s data shows that “delve” surged from near zero usage in published papers and articles in 1990 to nearly 18,000 instances by 2024. Graham noted that “no one uses it [delve] in spoken English,” emphasizing that such words are often employed to sound clever in writing rather than natural communication.
Following Graham’s post, founders appear to have adjusted their AI prompts or editing styles, with “delve” usage dropping to only 1.25% of YC applications in winter 2024. Instead, Graham commented in a May post that many founder emails now adopt a “hard-hitting journalistic style,” which he finds uncharacteristic of genuine founder communication. “It feels like being lied to,” he added, underscoring concerns about authenticity in AI-assisted applications.
Key Takeaways
- Y Combinator leaders report that founders are increasingly submitting AI-generated responses to application prompts.
- The startup accelerator has noted a rise in applications containing the word “wedge” and frequent use of em dashes—both recognized AI writing indicators.
- YC applications have grown 60% longer over the past three years, signaling founders’ use of AI to create more extensive responses.
As AI continues to evolve and integrate into startup culture, understanding these linguistic and stylistic shifts is crucial for both evaluators and founders. While AI tools can enhance clarity and polish, maintaining authenticity remains a key challenge in startup storytelling and investor relations.
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