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Secondary share sale calculator

A pure secondary transfer creates no new shares, so other holders are not diluted. This calculator shows what does change: the seller's remaining position, the buyer's new position and the gross proceeds.

Dilution to other holders
0.00%
Fully diluted shares after
11,875,000
Seller ownership before
33.68%
Seller ownership after
32.00%
Buyer ownership
1.68%
Gross proceeds to the seller
320,000

How this is calculated

  • The fully diluted share count is unchanged by a secondary transfer.
  • Seller ownership after = (seller shares − shares sold) ÷ fully diluted shares.
  • Buyer ownership = shares bought ÷ fully diluted shares.
  • Dilution to other holders is zero by construction.
  • Transfer restrictions, rights of first refusal and board approval still apply to any real transaction.

Assumptions

  • The sale is a transfer of existing shares between a seller and a buyer at an agreed price.
  • The company issues no new shares, so the fully diluted total is unchanged.
  • Proceeds shown are gross, before any fees, withholding or tax.

Limitations

  • Does not compute tax — treatment depends on jurisdiction, holding period and instrument.
  • Does not model board or shareholder consent, rights of first refusal or transfer restrictions.
  • Does not apply a liquidity discount to the reference price you enter.

Prepared by Perseids for general information. This tool runs on the numbers you enter, stores nothing and uses no company data. Results are illustrative and are not legal, tax or investment advice.

Run the same model on your real cap table, with your actual instruments.

Model this on your actual cap table in Perseids

Frequently asked questions

Does a secondary sale dilute other shareholders?
No. Ownership changes hands but no new shares are issued, so every other holder's percentage is unchanged. What can change is the reference price other parties then use.
Who has to approve a secondary?
Typically the company, under transfer provisions in the articles and shareholders' agreement, and often existing holders through a right of first refusal. Confirm the position in your own documents.

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