Rapport Therapeutics, Inc. filed an issuer free writing prospectus on October 27, 2026, pursuant to Rule 433, to update and supplement a preliminary prospectus supplement of the same date by adding pre-funded warrants to purchase shares of common stock as a new security in the company's ongoing public offering.

Key Highlights

  • New security added: The filing supplements the preliminary prospectus supplement primarily to reflect the addition of pre-funded warrants, and the shares of common stock issuable upon their exercise, to the securities being offered.
  • Exercise price: Each pre-funded warrant carries an exercise price of $0.001 per share, with the purchase price equal to the public offering price per share of common stock minus $0.001.
  • No expiration: According to the filing, the pre-funded warrants do not expire and are exercisable at any time after issuance, subject to a beneficial ownership limitation.
  • Beneficial ownership cap: Holders may not exercise pre-funded warrants to the extent doing so would result in ownership exceeding 4.99% of outstanding common stock, with the ability to increase that threshold to up to 19.99% upon at least 61 days' prior notice.
  • Underwriter option: The company has granted underwriters a 30-day option to purchase up to 15% of the total number of shares of common stock being offered (including shares underlying pre-funded warrants) in additional shares of common stock.
  • Intended use of proceeds: The company disclosed it currently intends to use net proceeds, together with existing cash, cash equivalents, and short-term investments, primarily to fund ongoing and planned clinical trials advancing RAP-219, other research and development, and for working capital and general corporate purposes.
  • No listing of warrants: The filing states the company does not intend to list the pre-funded warrants on the Nasdaq Global Market or any other national securities exchange or recognized trading system.

Rapport Therapeutics Expands Public Offering Terms With Pre-Funded Warrants

Rapport Therapeutics, Inc., whose common stock is listed on NASDAQ:RAPP, filed a free writing prospectus on October 27, 2026, under Registration Statement No. 333-294170. The document updates the preliminary prospectus supplement of the same date, with the primary change being the inclusion of pre-funded warrants as an alternative to common stock for investors who choose that option. The filing states that the information it contains "updates and, to the extent inconsistent, supersedes the information in the Preliminary Prospectus Supplement."

According to the filing, investors may purchase pre-funded warrants in lieu of common stock at a price equal to the public offering price per share minus $0.001, which is also the exercise price per warrant. The pre-funded warrants have no expiration date and may be exercised at any time after issuance, subject to the 4.99% beneficial ownership limitation described in the filing. That cap may be raised to a maximum of 19.99% by a holder giving at least 61 days' prior written notice to the company. The filing notes that lock-up restrictions described in the preliminary prospectus supplement "will not apply to issuance of common stock upon the exercise of the pre-funded warrants during the 90-day period following the date of the final prospectus supplement."

The filing discloses that specific dollar amounts for shares offered, the underwriters' option, and estimated net proceeds are not stated in this free writing prospectus and remain to be determined. The filing warns of "immediate and substantial dilution in the book value" for purchasers of securities in this offering and notes that further dilution may result from the exercise of outstanding options or the vesting and settlement of restricted stock units. The company disclosed it will not receive any meaningful additional funds from the exercise of the pre-funded warrants, though any such exercise would increase shares eligible for resale and result in dilution to existing stockholders.

What Was Disclosed

Rapport Therapeutics filed a free writing prospectus dated October 27, 2026, supplementing its preliminary prospectus supplement to add pre-funded warrants at a $0.001 exercise price to its public offering, with intended proceeds directed primarily toward clinical trials for RAP-219 and general corporate purposes.