What Anti-Dilution Protection Does to a Startup Cap Table in a Down Round

Anti-dilution protection is a provision in the terms of a preferred share class that adjusts the conversion price of those shares downward when new shares are issued at a lower price. A lower conversion price produces a greater number of common shares upon conversion for the protected investor. The most common form is broad-based weighted average anti-dilution, which calculates a new conversion price that accounts for both the price of the new issuance and the size of that issuance relative to the total share count.

The Distinction That Matters

Anti-dilution protection does not protect the investor from all dilution. It protects them from the valuation reduction of a down round by adjusting their effective ownership upward. The adjustment comes at the direct expense of founders, common shareholders, and any investor class that does not hold anti-dilution protection. A company that raises a down round has not only accepted a lower valuation. It has also triggered a share count adjustment for every protected investor, which further concentrates the economic impact of the down round on unprotected holders.

Full ratchet anti-dilution, a less common but more aggressive variant, adjusts the conversion price to match the down round price exactly, regardless of the round size. A single share issued at a lower price can trigger the adjustment for the full amount of protected stock. Founders should know which form of anti-dilution protection they have agreed to before signing any term sheet. Broad-based weighted average is the standard. Full ratchet is not.

Why It Surfaces in a Raise Process

In a down round, the legal team will identify every anti-dilution provision in the existing shareholder agreements and calculate the adjustment required for each protected class. This calculation must be reflected in the updated cap table before the new round closes. A founder who has not modeled the anti-dilution adjustment before the round opens will discover its effect on their own ownership percentage at the worst possible moment.

The Common Structural Error

The most common error is not identifying which share classes carry anti-dilution protection when the cap table is built. A cap table that records preferred shares without noting the anti-dilution terms of each class cannot be used to calculate the effect of a future down round and will produce an incorrect post-close ownership structure when the adjustment is eventually applied.

RELATED TERMS
- What a Liquidation Preference Clause Does to Founder Proceeds in an Exit
- What a Fully Diluted Cap Table Records
- How a Waterfall Analysis Distributes Exit Proceeds
- Cap Table Errors That Surface During Legal Due Diligence and the Infrastructure Required to Resolve Them

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