Capital Gains Tax Cut Doubled Startup Unicorn Odds, NBER Study Finds

A new National Bureau of Economic Research working paper offers striking evidence that tax policy can directly shape innovation outcomes. Economists Murillo Campello and Guilherme Junqueira of the University of Florida studied the Qualified Small Business Stock (QSBS) tax exemption, which Congress dramatically expanded in 2009 and 2010 to eliminate capital-gains taxes entirely on qualifying investments — newly issued shares in C corporations with under $50 million in assets across certain industries.

Drawing on a dataset of 158,000 investment deals from 2004 to 2022, the researchers compared behavior before and after the tax change across different investor types: angel investors using their own capital, venture-capital firms pooling outside money, and corporations ineligible for the QSBS break. The contrast between eligible and ineligible investors allowed a clean test of the tax break's effects.

The results were dramatic. After the 2009 changes, venture firms — the investors most responsive to the tax incentive — were 81% more likely to fund companies at the earliest, riskiest development stage. They also became significantly more willing to back startups carrying existing debt or operating in sectors where the VC had no prior experience, both classic markers of elevated risk. Failure rates for venture-backed firms rose 71% post-2009, reflecting this bolder risk appetite.

But the upside more than compensated. Valuations at successful exits were 131% higher after the tax cut than before, and startups whose investors qualified for the QSBS exemption were twice as likely to achieve unicorn status — valuations exceeding $1 billion. The mechanism is intuitive: by letting investors keep their gains, the tax break raised the expected return on risky bets, making it rational to swing harder even knowing many swings would miss.

The findings arrive as policymakers in several countries debate wealth taxes and higher capital-gains rates. The paper's implicit warning is that taxing investment returns doesn't merely redistribute wealth — it suppresses the risk-taking that produces breakthrough companies, jobs, and economic growth. The QSBS story suggests the cost of punitive capital taxation may be measured not just in dollars, but in unicorns that never get born.