Summit Partners Growth Equity Fund IX-A, L.P. filed a Form 144 notice on November 9, 2026, disclosing a proposed sale of 2,742,281 shares of Klaviyo, Inc. Series A common stock with an aggregate market value of $57,094,290.42.

Key Highlights

  • Proposed sale size: 2,742,281 shares of Klaviyo, Inc. Series A common stock, par value $0.001 per share.
  • Aggregate market value: $57,094,290.42 at the time of the notice.
  • Total shares outstanding: 130,150,680 shares of Series A common stock, according to the filing.
  • Broker designated: Barclays Capital Inc., 745 7th Avenue, New York, NY 10019.
  • Approximate date of sale: November 9, 2026, on the NYSE.
  • Original acquisition: 32,170,006 shares acquired on September 20, 2023, via pre-IPO transactions from Klaviyo, Inc.
  • Recent prior sales: Summit Partners Growth Equity Fund IX-A, L.P. sold 2,955,112 shares on August 11, 2026, for gross proceeds of $54,255,856.32.

Summit Partners Growth Equity Fund IX-A Files Proposed Sale Notice for Klaviyo Shares

Summit Partners Growth Equity Fund IX-A, L.P., identified in the filing as an "Owner" of Klaviyo, Inc. (NYSE:KVYO), submitted a Form 144 notice to the U.S. Securities and Exchange Commission on November 9, 2026. The notice covers a proposed sale of 2,742,281 shares of Klaviyo Series A common stock, par value $0.001 per share, with an aggregate market value stated as $57,094,290.42. The notice indicates Barclays Capital Inc. as the designated broker for the transaction.

According to the filing, the shares being offered for sale were originally acquired on September 20, 2023, through "Pre-IPO transactions" directly from Klaviyo, Inc. The total amount acquired in that transaction was reported as 32,170,006 shares, with payment described as "Equity interests in the Issuer were purchased pre-IPO." The filing states the total shares of Series A common stock outstanding as 130,150,680.

The filing also discloses that within the three months prior to this notice, Summit Partners Growth Equity Fund IX-A, L.P. sold 2,955,112 shares of the same class on August 11, 2026, generating gross proceeds of $54,255,856.32. The Form 144 was signed by Adam Hennessey. The notice includes a representation by the signing party that the seller "does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed," as stated in the filing's standard attestation language.

What Was Disclosed

Summit Partners Growth Equity Fund IX-A, L.P. filed a Form 144 notice proposing to sell 2,742,281 Klaviyo Series A common shares valued at approximately $57,094,290.42, through Barclays Capital Inc. on the NYSE, with shares originally acquired via pre-IPO transactions in September 2023.