Why "You Need a Co-Founder" Stopped Being True Around 2023
By Creatives Takeover Editorial Team · September 24, 2026
The rule didn't get repealed, it just stopped being true while everyone kept repeating it.
In 2020, First Round Capital published its 10 Year Project, a study of a decade of its own portfolio companies, and one finding traveled further than the rest: startups with more than one founder outperformed solo founders by 163 percent, and solo founders raised seed rounds at valuations 25 percent lower than teams. That single statistic became load bearing for an entire generation of startup advice. Y Combinator partners repeated it. Accelerator applications were built around it. "Find a co-founder before you apply" became close to a hard requirement in early stage fundraising.
By 2025, the underlying data had moved somewhere the advice never followed. Solo founders accounted for 36.3 percent of all new startups tracked by Carta, up from 23.7 percent in 2019, a 53 percent increase in six years. More strikingly, among startups that actually cross $1 million in annual recurring revenue, the single most common founder count is one. Not two. Not three. One. The rule that shaped a decade of founder advice was describing a world that, by the time most people quoted it, had already started to disappear.
Where the Rule Came From, and Why It Was Right at the Time
It's worth being precise about why "you need a co-founder" was good advice for as long as it was. Building a venture scale software company in the 2010s and into the early 2020s required a genuine division of labor that one person rarely possessed: someone who could write and ship production code, someone who could sell, and often someone who could design. Doing all three adequately, at the pace investors expected, was a real constraint on a single founder's output, not a mindset problem.
There was also a resilience argument. Building a company alone is lonely in a way that compounds under pressure, and a co-founder functioned as a built in second opinion during the moments when a solo founder's judgment was most likely to be compromised by exhaustion or sunk cost. Both of these were legitimate reasons, grounded in the actual constraints of building software before 2023, not folklore. The rule wasn't wrong. It was accurate to a set of conditions that later changed underneath it.
What Actually Changed Around 2023
The inflection point is unusually easy to date. ChatGPT launched in November 2022, and by early 2023 the broader wave of AI coding and building tools it triggered, GPT-4, and shortly after it a new generation of AI native coding environments, had started to genuinely change what a single person could produce in a day. The capacity constraint that had justified the co-founder rule for over a decade began shrinking fast, and it kept shrinking through 2024 and 2025 as those tools matured.
The cost data makes the shift concrete. A solo founder's full tooling stack, covering development, design, marketing and operations, now runs somewhere between $3,000 and $12,000 a year, a reduction of 95 to 98 percent compared to hiring even a lean team to cover the same functions. Reported operating margins for AI native solo founders now run 60 to 80 percent, against 10 to 20 percent for traditionally staffed companies covering the same ground. The three person job that used to require a technical co-founder, a designer and a marketer increasingly fits inside one person's week, not because that person got better, but because the tools around them did.
The Advice Took Two Years to Catch Up
The capability shift arrived in 2023. The data confirming it didn't fully show up until 2024 and 2025, and the advice itself still hasn't caught up even now. Carta's own reporting shows the sharpest jump in solo founder share happened specifically between 2024 and 2025, rising from 30.5 to 36.3 percent in that single window, which lines up almost exactly with the period when AI coding assistants went from a novelty to a default part of how software gets built.
Despite that shift, venture capital allocation moved at a completely different pace. Solo led startups founded in 2024 captured only 14.7 percent of the cash raised across priced equity rounds that year, even as they made up more than a third of new companies. Two-founder teams still represent 37 percent of VC-backed companies, the single most common configuration by a wide margin, while solo founders sit at just 20 percent of VC-backed companies despite being the largest group among the companies actually reaching meaningful revenue. The rule stopped describing reality in the building phase well before it stopped describing reality in the fundraising phase, and fundraising still hasn't finished catching up.
The Risk the Old Rule Never Priced In
There's a second piece of data that rarely makes it into the "find a co-founder" conversation, and it matters just as much as the productivity numbers. Among VC-backed two-founder teams, 24 percent lose a co-founder by year four. By year eight, that number climbs to nearly 40 percent. A startup's foundational structural decision, who you build the company with, carries close to a coin flip's worth of risk over the life of the company, and that risk sits entirely outside a founder's control once a co-founder decides to leave.
Set next to that, the case for defaulting into a co-founder relationship purely to satisfy an old rule of thumb looks considerably weaker. A founder who takes on a co-founder mainly because conventional wisdom said to is accepting a real, well documented failure mode in exchange for a productivity advantage that, for a meaningful share of software businesses, no longer requires a second person to capture.
Why "Solo Founders Just Got Braver" Is the Wrong Lesson
The comfortable explanation for the rise in solo founding is cultural: a new generation of founders more comfortable with risk, more willing to go it alone, less interested in splitting equity. That story is appealing because it doesn't require revisiting whether the old advice was ever fully correct. It is also not what the data shows.
The actual driver is structural, not psychological. The 95 to 98 percent collapse in tooling costs and the shift in what one person can execute in a day changed the underlying math of company building, and founder behavior followed the math rather than leading it. Attributing the shift to a cultural mood misses the more useful and more durable insight: the capacity constraint that made the old rule true has measurably shrunk, and it will likely keep shrinking, which means the advice built on top of it needs to be re-evaluated on the same schedule as the tools, not treated as a fixed law of company building.
What This Actually Means for a Founder Building Right Now
The instinctive takeaway is "go solo," which overcorrects just as hard as the old blanket rule did in the other direction. Some companies still genuinely require a second founder, particularly ventures with deep technical or regulatory complexity that no amount of AI tooling currently compresses into one person's bandwidth. The sharper version of the lesson replaces a categorical rule with a specific diagnostic: instead of asking "do I need a co-founder," ask what specific function you are missing right now, and then ask honestly whether that function is something you can buy as a tool, learn well enough to do adequately, or genuinely cannot access without bringing in a second founder.
That question would have had a very different answer in 2019 than it does today for most software businesses, and the honest answer for any given founder now depends far more on the specific gap they're facing than on a decade old statistic from a study that closed its data collection before any of the tools reshaping this question even existed.
Five Things Worth Taking From This
A statistic can be completely accurate and still stop describing reality. First Round Capital's 163 percent figure was a real, well conducted finding about the 2010s. It was never a permanent law, and treating it as one meant an entire industry kept repeating advice years after its foundation had shifted.
The capability shift and the advice shift happen on different timelines. AI tooling changed what a single founder could execute starting in 2023. The data proving that shift didn't fully surface until 2024 and 2025, and the funding behavior built on the old advice still hasn't caught up even now.
Institutional behavior lags outcome data more than most founders assume. Solo founders make up the largest group among companies reaching $1 million in revenue, yet they still capture a small fraction of venture dollars, a gap that reflects investor habit more than investor evidence.
The co-founder relationship carries a specific, measurable risk that the old advice never priced in. A close to 40 percent chance of losing a co-founder within eight years is a real cost of that structure, not a hypothetical one, and it belongs in the same conversation as the productivity case for having a second founder.
The right question replaced a rule, it didn't just get more lenient. The useful version of this update isn't "co-founders are optional now." It's that the decision has to be made against a specific, current gap in what one founder can execute, not against a statistic that was collected before the tools available today existed.
The rule didn't get repealed by a memo or a study everyone agreed to cite instead. It just quietly stopped being true while most of the industry kept repeating it, and the gap between when that happened and when anyone noticed is the actual story here.