Latest Period
Q1 2026
Security Snapshot
Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share (MRSN) Institutional Ownership
CUSIP: 59045L106
13F Institutional Holders and Ownership History from Q2 2017 to Q1 2026
Institutions Reporting
0
Shares (Excl. Options)
0
Price
$0.31
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- Security type / class
- Equity / Common Stock, par value $0.0001 per share
- Symbol
- MRSN on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 0
- Total 13F value
- $0
- Share change
- -99
- Value change
- -$2,864
- Number of holders
- 0
- Shares outstanding
- 4,992,318
- SEC-reported price per share
- $0.31
- Insider filing price
- $0.31
Latest holder snapshot
4 signals
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- MRSN - Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share is tracked under CUSIP 59045L106.
- 0 institutions reported positions in Q1 2026.
- 4 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 3 to 0 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $2,864 to $0.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 0 institutions filings for Q1 2026.
Security key
59045L106
Latest holder period
Q1 2026
13F holders
0
13D/G owners
4
CIK / CUSIP context first
Open Q1 2026 holders
MRSN full holder history
Mersana Therapeutics, Inc. SEC filings
Mersana Therapeutics, Inc. company facts
Mersana Therapeutics, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 59045L106:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
4
Security
MRSN
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| Nextech Crossover I GP S.a r.l. | 10% | $4,344,209 | 12,067,246 | Nextech Crossover I GP S.a. r.l. | 20 Dec 2024 | |||
| VANGUARD GROUP INC | 6.7% | $3,015,996 | 8,377,767 | The Vanguard Group | 31 Mar 2025 | |||
| BlackRock, Inc. | 3% | -53% | $1,103,358 | -$1,338,033 | 3,761,876 | -55% | BlackRock, Inc. | 30 Jun 2025 |
| Venrock Healthcare Capital Partners III, L.P. | 2.9% | -68% | $1,286,757 | -$2,406,047 | 3,574,325 | -65% | Venrock Healthcare Capital Partners III, L.P. | 31 Mar 2025 |
As of 31 Mar 2026, 0 institutional investors reported holding 0 shares of Mersana Therapeutics, Inc. - Common Stock, par value $0.0001 per share (MRSN). This represents 0% of the company’s total 4,992,318 outstanding shares.
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
36
Latest
Q1 2026
Rows shown
1-25 of 36
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 0 | $0 | -$2,864 | $0.31 | 0 |
| 2025 Q4 | 99 | $2,864 | -$411,796 | $28.93 | 3 |
| 2025 Q3 | 55,398 | $410,881 | -$31,447,580 | $7.76 | 5 |
| 2025 Q2 | 77,200,692 | $22,849,022 | -$3,437,337 | $0.30 | 80 |
| 2025 Q1 | 87,949,584 | $30,264,885 | -$35,777,339 | $0.34 | 109 |
| 2024 Q4 | 104,303,178 | $149,151,003 | -$24,954,008 | $1.43 | 129 |
| 2024 Q3 | 116,077,343 | $219,445,627 | +$3,272,056 | $1.89 | 115 |
| 2024 Q2 | 114,206,357 | $229,554,281 | -$23,968,075 | $2.01 | 120 |
| 2024 Q1 | 117,492,700 | $526,342,513 | +$23,958,185 | $4.48 | 124 |
| 2023 Q4 | 113,095,763 | $262,379,163 | +$21,039,242 | $2.32 | 104 |
| 2023 Q3 | 113,738,083 | $144,445,790 | -$76,640,644 | $1.27 | 127 |
| 2023 Q2 | 112,399,497 | $369,792,616 | +$12,845,282 | $3.29 | 145 |
| 2023 Q1 | 106,632,085 | $437,242,303 | +$17,660,953 | $4.11 | 156 |
| 2022 Q4 | 101,429,361 | $594,377,218 | +$41,420,886 | $5.86 | 150 |
| 2022 Q3 | 92,449,667 | $624,973,128 | +$39,050,654 | $6.76 | 147 |
| 2022 Q2 | 88,302,299 | $407,955,031 | +$36,774,738 | $4.62 | 121 |
| 2022 Q1 | 80,872,131 | $322,721,381 | +$33,055,220 | $3.99 | 127 |
| 2021 Q4 | 70,190,994 | $436,594,924 | -$9,658,535 | $6.22 | 120 |
| 2021 Q3 | 68,748,658 | $648,298,103 | -$40,839,729 | $9.43 | 108 |
| 2021 Q2 | 69,773,540 | $946,957,788 | -$9,186,549 | $13.58 | 129 |
| 2021 Q1 | 68,154,863 | $1,102,711,080 | -$36,197,720 | $16.18 | 130 |
| 2020 Q4 | 68,137,745 | $1,813,136,515 | +$51,864,511 | $26.61 | 147 |
| 2020 Q3 | 67,909,081 | $1,264,489,156 | +$48,626,981 | $18.62 | 132 |
| 2020 Q2 | 64,727,492 | $1,514,580,389 | +$684,777,923 | $23.40 | 129 |
| 2020 Q1 | 40,118,913 | $233,891,407 | +$26,078,897 | $5.83 | 82 |