GOSS Gossamer Bio, Inc.
Executive Summary
Four mega-passive institutional investors (State Street, Invesco, UBS, BofA) significantly increased their GOSS holdings in Q3 2025, adding $22.2M in net new positions, while two sellers (Fidelity, Morgan Stanley) trimmed $2.2M. The buying is dominated by passive/index funds, likely reflecting index rebalancing or systematic allocation rather than a fundamental thesis, and the cluster's mixed net conviction and historical underperformance on GOSS calls (0% win rate at T+20) suggest limited trading signal.
Key Financial Metrics
Institutional Positions
Net institutional flow: $20.0M
▲ Buyers (4)
| Institution | Action | Change | Position Value | Value Δ |
|---|---|---|---|---|
| State Street | ADD | +56.5% | $10.2M | $7.2M |
| Invesco | ADD | +47.2% | $926.0K | $632.0K |
| UBS | DOUBLED | +785.7% | $7.3M | $6.9M |
| BofA | DOUBLED | +4196.2% | $7.6M | $7.5M |
▼ Sellers (2)
| Institution | Action | Change | Prev Value | Value Δ |
|---|---|---|---|---|
| Fidelity | TRIM | -44.2% | $9.0M | $1.7M |
| Morgan Stanley | TRIM | -30.8% | $1.0M | $483.0K |
Actionable Insight
The cluster is entirely passive/index-driven with no active manager conviction — treat as index rebalancing noise, not a fundamental signal. Monitor for any active fund 13F filings or insider buying to confirm a real thesis shift. Given GOSS's $37M market cap, the $20M net inflow is large relative to float but likely mechanical.
Key Facts
- 4 buyers added $22.2M net; 2 sellers reduced $2.2M; aggregate net buying of $20.0M
- All 6 institutions are mega-passive (index/rebalancing) — no active managers or hedge funds involved
- UBS and BofA both DOUBLED positions, with BofA increasing shares by 4,196% (67K → 2.88M shares)
- Fidelity trimmed 44.2% of its position (7.32M → 4.09M shares) but value rose $1.7M due to stock appreciation
- Historical GOSS reports show 0% win rate at T+20 across 3 settled calls, with avg alpha -25.16% vs SPY
Financial Impact
4 passive institutions accumulated $22.2M in new GOSS positions while 2 passive institutions reduced holdings by $2.2M, for a net institutional inflow of $20.0M in Q3 2025
Risk Factors
- 13F data is 45+ days stale; positions may have been unwound since quarter-end
- Passive flows can reverse on next rebalance date with no fundamental catalyst
- Historical GOSS reports have 0% win rate at T+20 — prior cluster signals on this ticker have been unreliable
Market Snapshot
Documents Analyzed
This report is based on 1 institutional 13F filing from SEC EDGAR.
| Document | Accession Number |
|---|---|
| INST-CLUSTER Data (Synthetic) | inst-cluster-GOSS-2025-Q3 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
|
Jun 11, 2026
2d ago
|
Institutional Cluster
| $0.1554 awaiting T+1 | awaiting T+1 | — | — |
|
Jun 2, 2026
11d ago
|
8-K
| $0.2000 $0.1880 | ▼ −6.00% | ▼ −5.31% | — |
|
May 18, 2026
26d ago
|
DEFA14A
| $0.1930 $0.1990 | ▲ +3.11% | ▲ +3.76% | — |
|
Apr 24, 2026
7w ago
|
DEFA14A
| $0.3490 $0.3450 | ▼ −1.15% | ▼ −0.66% | — |
|
Mar 19, 2026
12w ago
|
EFFECT
| $0.4520 $0.4220 | ▼ −6.64% | ▼ −4.90% | — |
US Market Status
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