What a Down Round Actually Does to Founder Ownership – Beyond the Valuation Headline

A company raises a Series A at a £30 million pre-money valuation, down from a £45 million Seed round valuation eighteen months earlier. The headline is difficult: the company has lost a third of its valuation. The founders understand this. They have accepted the dilution that comes with the new round. What they have not yet calculated is the second layer of dilution — the anti-dilution adjustments triggered by the down round that will further reduce their ownership before the new investor's shares are even issued.

The Seed investors hold broad-based weighted average anti-dilution protection. The down round triggers an adjustment to their conversion price. The formula recalculates the price at which their preferred shares convert to common, producing a lower price and therefore a greater number of common shares. Those additional shares come from the common pool — specifically, from the founders' ownership and the ungranted option pool reserve. The founders' post-close ownership is not the simple result of pre-money valuation minus the new investment divided by post-money valuation. It is that result, minus the anti-dilution adjustment to the Seed investors, minus the option pool top-up that the new investor requires as a condition of closing. The headline valuation implies one ownership structure. The actual ownership structure is materially different, and the founders will not see it until the legal team produces the post-close cap table.

THE MECHANICS OF ANTI-DILUTION ADJUSTMENT IN A DOWN ROUND

Anti-dilution protection operates through a formula that adjusts the conversion price of preferred shares when new shares are issued at a lower price than the preferred shares were originally purchased. The most common form is broad-based weighted average anti-dilution, which calculates a new conversion price based on the weighted average of the old conversion price and the new issue price, adjusted for the size of the new issuance relative to the total fully diluted share count.

The formula produces a new conversion price that is lower than the original conversion price but higher than the down round price. The lower conversion price means that each preferred share converts into more common shares than it would have converted into before the down round. The additional common shares are not created from nothing. They are drawn from the common share pool, which consists primarily of founder shares and the ungranted option pool reserve. The founders' ownership percentage decreases by more than the simple dilution calculation would indicate, because the anti-dilution adjustment has increased the share count of the preferred holders without increasing the total number of shares in the company.

The practical effect can be illustrated with a simplified example. A company has 10,000,000 fully diluted shares before the down round. Founders hold 6,000,000 shares, or sixty percent. Seed investors hold 3,000,000 preferred shares at a conversion price of £3.00 per share, representing thirty percent on a fully diluted basis. The remaining 1,000,000 shares are in the ungranted option pool. The company raises a down round at £2.00 per share, issuing 2,000,000 new shares to the Series A investor. The simple dilution calculation would show the founders' ownership declining from sixty percent to approximately fifty percent after the new issuance. But the anti-dilution adjustment recalculates the Seed investors' conversion price to approximately £2.60 using the broad-based weighted average formula. Their 3,000,000 preferred shares now convert into approximately 3,460,000 common shares rather than 3,000,000. The additional 460,000 shares come from the common pool. The founders' effective ownership after both the new issuance and the anti-dilution adjustment is approximately forty-six percent — four percentage points lower than the simple dilution calculation suggested.

The four percentage point difference is not a rounding error. In a company with a post-money valuation of £34 million, four percentage points of equity represents £1.36 million of value transferred from founders to preferred investors through the operation of the anti-dilution clause. This transfer is contractual, automatic, and frequently invisible to founders until the cap table is recalculated after the round closes.

THE OPTION POOL SHUFFLE IN A DOWN ROUND

A down round compounds the dilution effect through a second mechanism: the option pool shuffle. In most priced rounds, the new investor requires the company to maintain or increase the ungranted option pool as a condition of closing. The pool top-up is typically taken from the pre-money valuation, which means the shares required to increase the pool are created from the existing shareholders' equity before the new investor's ownership percentage is calculated.

In a down round, the option pool shuffle interacts with the anti-dilution adjustment in a way that further concentrates the dilution on founders. The pool top-up reduces the common share pool before the anti-dilution formula is applied, which means the anti-dilution adjustment operates on a smaller common base. The Seed investors' additional shares represent a larger proportion of the reduced common pool. The founders absorb both the pool top-up and the anti-dilution adjustment sequentially, and the combined effect is larger than either would be independently.

A founder who negotiates the term sheet without modelling the combined effect of the pool top-up and the anti-dilution adjustment is negotiating without knowing their own post-close ownership position. The term sheet states the pre-money valuation and the new investment amount. It does not state the post-anti-dilution ownership structure. That must be calculated by the company's legal and financial advisors before the term sheet is signed, or it will be discovered afterwards when the cap table is updated.

WHAT THE FOUNDER SHOULD MODEL BEFORE THE TERM SHEET

Before accepting a term sheet for a down round, the founding team should model five scenarios of the post-close cap table.

The first scenario is the simple dilution calculation: pre-money valuation minus the new investment, with no anti-dilution adjustment and no option pool top-up. This scenario establishes the baseline that the term sheet headline implies.

The second scenario adds the option pool top-up required by the new investor, taken from the pre-money valuation. This scenario shows the dilution effect of the pool top-up alone, before anti-dilution adjustments.

The third scenario adds the anti-dilution adjustment for each protected share class, using the broad-based weighted average formula. This scenario shows the combined effect of the pool top-up and the anti-dilution adjustment on the founders' post-close ownership.

The fourth scenario applies full ratchet anti-dilution instead of broad-based weighted average, to show the worst-case outcome if the preferred shareholders have full ratchet protection or if the company's legal team identifies a full ratchet clause that had not previously been documented in the cap table.

The fifth scenario varies the down round price by ten percent in either direction, to show the sensitivity of the founders' post-close ownership to the round price. A ten percent lower price produces a larger anti-dilution adjustment. A ten percent higher price reduces it. The founders should know both figures before the term sheet negotiation begins.

These five scenarios should be produced by the company's legal counsel in collaboration with the financial team, not by the investor's counsel. A founder who relies on the investor's legal team to produce the post-close cap table has outsourced the calculation of their own ownership to the party on the other side of the negotiation.

COMMON STRUCTURAL PROBLEMS IN DOWN ROUND MODELING

The most common problem is the cap table that does not record anti-dilution terms by share class. A cap table built at Seed stage that lists preferred shares without noting the anti-dilution provision applicable to each class cannot be used to calculate the anti-dilution adjustment when a down round occurs. The legal team must first reconstruct the anti-dilution terms from the original investment agreements, which introduces delay at a moment when time is constrained.

The second problem is the anti-dilution formula calculation performed incorrectly. The broad-based weighted average formula requires the total fully diluted share count, the number of shares being issued in the down round, the original conversion price of the protected shares, and the down round price per share. An error in any one of these inputs produces an incorrect conversion price and an incorrect post-close cap table. The calculation should be performed by two independent parties and the results compared before the term sheet is signed.

The third problem is the option pool top-up taken post-money rather than pre-money, which produces a different dilution outcome. In most term sheet structures, the pool top-up is a pre-money event that affects existing shareholders only. A founder who models the top-up as a post-money event will overstate their post-close ownership. The term sheet language must be reviewed carefully to determine whether the pool requirement is "post-money" or "pre-money," because the drafting convention is not standardised across all law firms.

HOW THE FFI STANDARD DEFINES THE REQUIREMENT

The FFI Standard addresses down round modeling in Book 3 (Capital Structure and Equity). Level 2 compliance requires a fully diluted cap table that records the anti-dilution terms for each preferred share class, including the type of anti-dilution protection and the original conversion price. The Standard requires that the anti-dilution adjustment be modeled before any term sheet is signed, not during the legal close process, and that the post-close cap table reflect the adjustment for all protected classes. The Standard further requires that the option pool treatment be confirmed from the term sheet language and modeled at both pre-money and post-money scenarios to identify the impact on founder ownership. Full compliance criteria are at ffistandard.org/glossary/anti-dilution-protection/.

THE LAYER ENGAGEMENT

The Structure layer engagement addresses cap table preparation for down round scenarios specifically. The engagement produces a fully diluted cap table with anti-dilution terms documented for each share class, models the five post-close ownership scenarios described above, and produces a term sheet analysis that shows the founder the combined effect of the pool top-up and the anti-dilution adjustment before the term sheet is signed. For companies that are not yet in a down round process but want to understand their exposure, the Blueprint Diagnostic at theoakworth.com/portal/blueprint/ identifies whether the cap table documentation is sufficient to support anti-dilution modeling and what must be remediated.

The Investor Readiness Scorecard at theoakworth.com/portal/scorecard/ assesses the capital structure domain across sixteen questions, identifying whether anti-dilution documentation gaps exist and whether they represent the primary infrastructure risk or one of several.

RELATED INSIGHTS
- The Assumption Layer in a Startup Financial Model Is Not a Tab. It Is a Governance Document.
- The Headcount Model Most Startup Financial Models Either Miss or Build Incorrectly
- Why a Startup Valuation Without a Documented Methodology Does Not Survive Series A Diligence
- Cap Table Errors That Surface During Legal Due Diligence and the Infrastructure Required to Resolve Them
- How a KPI Framework Connects the Annual Operating Plan to Board-Level Financial Governance

Tool: Blueprint Diagnostic