--- url: 'https://qubit.capital/blog/biotech-dilution-management-follow-on-rounds' title: 'Follow-On Round Dilution in Biotech: The Math and the Syndicate' author: name: Mayur Toshniwal url: 'https://qubit.capital/blog/author/mayur' date: '2026-01-02T04:05:00+05:30' modified: '2026-10-05T17:23:30+05:30' type: post categories: - Industry-Specific Insights image: 'https://qubit.capital/wp-content/uploads/2026/10/biotech-dilution-management-follow-on-rounds.webp' published: true --- # Follow-On Round Dilution in Biotech: The Math and the Syndicate Table of Contents - [Key Takeaways](#key-takeaways) - [How to Calculate Follow-on Round Dilution](#how-to-calculate-follow-on-round-dilution) - [Up, Flat and Down Follow-on Rounds](#up-flat-and-down-follow-on-rounds) - [Biotech Syndicate Investors and the Insider Portion](#biotech-syndicate-investors-and-the-insider-portion) - [Insider Rounds, Bridges and Pay-to-Play](#insider-rounds-bridges-and-pay-to-play) - [Ways to Limit Biotech Startup Dilution](#ways-to-limit-biotech-startup-dilution) - [Before the Next Round](#before-the-next-round) ## Key Takeaways - Follow-on round dilution equals the new money divided by the post-money valuation. - Healthcare startups on Carta had median dilution of 22% at Series A and 11% at Series B in Q4 2024. - Your syndicate decides how much of each round insiders fund, and often the price. - Pro rata rights keep your investors’ stakes whole. They do nothing for yours. Follow-on round dilution is the share of your company that new money buys: the round size divided by the post-money valuation. Raise $40 million at a $120 million post-money, and every existing holder, founders included, gives up one third. Biotech companies raise these rounds often, because drug programs need years of funding before any revenue. Among healthcare startups on Carta, median dilution was [22% at Series A](https://carta.com/data/industry-spotlight-healthcare-2024/) in Q4 2024, against 11% at Series B. This page covers the calculation, how the round’s price changes it, and what your syndicate does to it. ## How to Calculate Follow-on Round Dilution Start with the post-money valuation: the pre-money valuation (what the company is worth before the round) plus the new money. New investors own the new money divided by that figure. Every existing holder shrinks by the same proportion. Take a small round: $1 million raised at a $500,000 pre-money valuation gives a $1.5 million post-money. The new investor owns two thirds, so the founders’ stake shrinks by about 67%. An earlier version of this page put that figure at 33%, which was wrong. Run the math on a fully diluted basis, counting every share, option, warrant and convertible that could become stock. Simple agreements for future equity (SAFEs) and notes that convert in the round dilute you too. So does an option pool top-up, which term sheets usually place before the new money. ## Up, Flat and Down Follow-on Rounds The price of the round matters more than its size. The table shows one $40 million Series B at three prices, for founders holding 40% going in. These are our example numbers, not market data. | Series B pre-money | Post-money | New investors own | Founders after (from 40%) | | --- | --- | --- | --- | | $120M (up round) | $160M | 25% | 30% | | $80M (flat round) | $120M | 33% | 27% | | $40M (down round) | $80M | 50% | 20% | ![Infographic: Up, Flat and Down Follow-on Rounds. Price Beats Size; Hidden Down Round Cost; Ratchet Versus Average.](https://qubit.capital/wp-content/uploads/2026/10/follow-on-round-dilution-in-biotech-the-math-and-the-syndicate-1-up-flat-and-dow.webp) A down round costs founders more than the table shows. Earlier investors often hold anti-dilution terms that give them extra shares when the price falls. A full ratchet resets their price to the new, lower one. A broad-based weighted average moves it only part of the way, so the cost is shared. Check where your price sits against [biotech valuation benchmarks for Series A and B](https://qubit.capital/blog/biotech-series-a-b-valuation-benchmarks) before a term sheet arrives. ## Biotech Syndicate Investors and the Insider Portion In biotech follow-on financing, most of the money comes from investors already on your cap table. That group of funds is your syndicate. Their reserves decide how much of each round you must find from outsiders. Insiders are expected to keep paying in. Bruce Booth, a partner at Atlas Venture, describes the norm in [Twenty Years In Early Stage Biotech VC](https://lifescivc.com/2025/10/twenty-years-in-early-stage-biotech-vc-part-3-business/): > “All existing investors are expected to do their pro rata of the insider portion of those future rounds, especially in tough markets.” Pro rata means each fund buys its current share of the new round. In the flat example above, Series A funds holding 45% put in $18 million and stay at 45%. Founders still fall from 40% to 27%. ## Insider Rounds, Bridges and Pay-to-Play A bridge round is a smaller raise, usually from insiders, that buys time to the next milestone. In healthcare they are common. On the same Carta data, the bridge-round rate reached 42% at seed and 36% at Series A in Q4 2023. A bridge rewards whoever writes it. Jack Januszewski, a vice president and healthcare investor at West Harlem Innovation Network, told Carta that a bridge round: > “can not only be prudent, it can also be an incredibly good opportunity as an investor to grab more value.” That value comes out of your stake. Size a bridge to one milestone, so the dilution buys a step up in value. Insiders who skip their share can face pay-to-play penalties; Booth gives conversion to common at 10 to 1 as an example. ## Ways to Limit Biotech Startup Dilution Raise to a milestone, not to a calendar date. A round that ends at clinical data can price the next one higher. Map each round to its milestone in a [funding roadmap for your biotech](https://qubit.capital/blog/funding-for-biotech-startups-sustainable-growth). Use money that does not cost equity where it fits. Grants, partnerships and [venture debt or royalty financing](https://qubit.capital/blog/biotech-venture-debt-royalty-financing) can stretch a round to its milestone. Pick funds for their reserves, not only their cheque. Ask every name on your [shortlist of biotech VC firms](https://qubit.capital/blog/top-biotech-vc-firms) how much it holds back for your next two rounds. A syndicate of small cheques can look strong at Series A and stall at Series B. ## Before the Next Round Model your next two rounds at three prices before you sign anything. Then ask each syndicate member, in writing, what it plans to put into the next round. Those two answers say more about your future stake than any headline valuation. Qubit Capital’s [biotech fundraising assistance](https://qubit.capital/industries/biotech) helps founders price follow-on rounds and line up the investors behind them. Keep the lab work moving while our team runs the raise.