MRSN is no longer listed. Its last trade on record was Jan 6, 2026. The price and figures on this page are from its last trading day and final filings, and are no longer updated.
Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in MRSN held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | IFP Advisors, Inc | 3 | $87 | 0.0% | 0.000% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in MRSN — a direct measure of their conviction.
Filings activity in MRSN during Q1 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 1 | 98% | 0.00% | 45.52 pp | $0M | 100% |
| Q4 2025 | 50 | +8.7% | 45.52% | 17.89 pp | $62M | +166% |
| Q3 2025 | 46 | 47% | 63.41% | +4.40 pp | $23M | +7.5% |
| Q2 2025 | 86 | 24% | 59.01% | 8.69 pp | $22M | 25% |
| Q1 2025 | 113 | 14% | 67.70% | 14.89 pp | $29M | 80% |
| Q4 2024 | 132 | +14% | 82.59% | 6.37 pp | $148M | 30% |
| Q3 2024 | 116 | 3.3% | 88.96% | +0.72 pp | $210M | 5.2% |
| Q2 2024 | 120 | — | 88.24% | — | $222M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying MRSN stock.
Based on Q1 2026 13F filings, institutional ownership of Mersana Therapeutics, Inc. stands at 0.0%, held across 1 reporting institutions.
IFP Advisors, Inc is the largest reported institutional holder of MRSN, with approximately 3 shares worth $0.00B as of Q1 2026.
No marquee "smart money" managers (Berkshire, Burry, ARK, Tiger Global, Pershing Square, Baupost, etc.) currently appear among the top 25 institutional holders of MRSN.
Our composite Smart Money Score for MRSN is 4 out of 100 (Heavy Distribution). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
0 institutions opened new positions in MRSN during Q1 2026, while 48 fully exited. 0 added to existing positions and 0 trimmed.
MRSN institutional ownership fell by 45.52 percentage points quarter-over-quarter, with a net change of -49 holders.
The top 10 institutions account for 100.0% of all reported 13F value in MRSN, and the top 25 account for 100.0%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Mersana Therapeutics, Inc. (MRSN) Institutional Ownership