David M. Mott - 06 Jan 2026 Form 4 Insider Report for Mersana Therapeutics, Inc. (MRSN)

Role
Director
Signature
/s/ David Mott
Issuer symbol
MRSN
Transactions as of
06 Jan 2026
Net transactions value
$0
Form type
4
Filing time
06 Jan 2026, 16:39:24 UTC
Previous filing
24 Jun 2025
Next filing
23 Feb 2026
SEC
View on sec.gov

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Quoteable Key Fact

"David M. Mott filed Form 4 for Mersana Therapeutics, Inc. (MRSN) on 06 Jan 2026."

Quick Takeaways

  • This page summarizes David M. Mott's Form 4 filing for Mersana Therapeutics, Inc. (MRSN).
  • 15 reported transactions and 13 derivative rows are listed below.
  • Filing timestamp: 06 Jan 2026, 16:39.

What Changed

  • Previous filing in this sequence was filed on 24 Jun 2025.
  • Current net transaction value: $0.

Why This Matters

  • This tells you what this filing adds before you inspect full transaction and derivative tables.
  • You can trace every row back to the original SEC filing document.

Official SEC Source

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

See Original Filing

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
MOTT DAVID M Director C/O MERSANA THERAPEUTICS, INC., 840 MEMORIAL DRIVE, CAMBRIDGE /s/ David Mott 06 Jan 2026 0001219871

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MRSN Common Stock Disposition pursuant to a tender of shares in a change of control transaction -23,546 -100% 0 06 Jan 2026 Direct F1, F2
transaction MRSN Common Stock Disposition pursuant to a tender of shares in a change of control transaction -383 -100% 0 06 Jan 2026 See Footnote F1, F2, F5

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MRSN Stock Option (right to buy) Disposed to Issuer -2,460 -100% 0 06 Jan 2026 Common Stock 2,460 $9.08 Direct F3
transaction MRSN Stock Option (right to buy) Disposed to Issuer -264 -100% 0 06 Jan 2026 Common Stock 264 $434.75 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -400 -100% 0 06 Jan 2026 Common Stock 400 $306.75 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -1,011 -100% 0 06 Jan 2026 Common Stock 1,011 $107.75 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -1,000 -100% 0 06 Jan 2026 Common Stock 1,000 $107.75 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -788 -100% 0 06 Jan 2026 Common Stock 788 $134.00 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -368 -100% 0 06 Jan 2026 Common Stock 368 $572.50 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -181 -100% 0 06 Jan 2026 Common Stock 181 $527.25 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -1,002 -100% 0 06 Jan 2026 Common Stock 1,002 $372.50 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -740 -100% 0 06 Jan 2026 Common Stock 740 $161.00 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -1,800 -100% 0 06 Jan 2026 Common Stock 1,800 $90.50 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -734 -100% 0 06 Jan 2026 Common Stock 734 $216.00 Direct F4
transaction MRSN Stock Option (right to buy) Disposed to Issuer -2,200 -100% 0 06 Jan 2026 Common Stock 2,200 $56.50 Direct F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

David M. Mott is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id Content
F1 Pursuant to the terms of that certain Agreement and Plan of Merger (the "Merger Agreement"), by and among the Issuer, Day One Biopharmaceuticals, Inc. ("Parent") and Parent's direct wholly-owned subsidiary, Emerald Merger Sub, Inc. ("Purchaser"), dated as of November 12, 2025, the shares (the "Shares") of common stock, par value $0.0001 per share, of the Issuer (the "Common Stock") that were tendered to Purchaser prior to the expiration time of the Offer were exchanged for: (i) $25.00 per Share, net to the stockholder in cash, without interest and less any applicable tax withholding (the "Upfront Cash Consideration"), plus (ii) one non-tradeable contingent value right per Share (each, a "CVR"),
F2 (continued from footnote 1) which represents the right to receive certain contingent milestone payments of up to an aggregate of $30.25 per CVR in cash, without interest and less any applicable tax withholding, upon the achievement of certain specified milestones in accordance with the terms and subject to the conditions of a contingent value rights agreement entered into by Parent and the rights agent (the Upfront Cash Consideration plus one CVR, collectively, the "Offer Price"). After completion of the tender offer, pursuant to the terms of the Merger Agreement, Purchaser merged with and into the Issuer, effective as of January 6, 2026 (the "Effective Time"), with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent.
F3 Pursuant to the terms of the Merger Agreement, effective as of immediately prior to the Effective Time, each option to purchase shares of Common Stock ("Issuer Option") that was outstanding and unexercised as of immediately prior to the Effective Time and had an exercise price per Share that was less than the Upfront Cash Consideration (each, a "Cash-Out Option"), became fully vested and was automatically cancelled and converted into the right to receive, without interest and subject to deduction for any required tax withholding, (i) the Offer Price minus (ii) the exercise price payable per share of Common Stock underlying such Cash-Out Option.
F4 Pursuant to the terms of the Merger Agreement, effective as of 10 business days prior to the closing of the Merger (the "Acceleration Date"), each Issuer Option then outstanding and unexercised that had an exercise price per Share that was equal to or greater than the Upfront Cash Consideration (each, an "OTM Option"), became fully vested and exercisable up to and through the closing of regular trading on the Nasdaq Stock Market on the fifth business day following the Acceleration Date (the "Last Exercise Date"). OTM Options not exercised on or prior to the Last Exercise Date were cancelled and ceased to exist as of the Effective Time, and no consideration was delivered in exchange for such OTM Option.
F5 The securities were held directly by the David Mott Declaration of Trust dated May 31, 2001, as amended (the "Mott Trust"). The Reporting Person disclaims beneficial ownership within the meaning of Section 16 of the Securities Act of 1934, as amended, or otherwise of such portion of the securities held by the Mott Trust in which the Reporting Person has no pecuniary interest.

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