The cluster shows a clear divergence: passive/index funds are accumulating while active managers are reducing. This pattern often reflects index rebalancing or passive inflows rather than a fundamental catalyst. Monitor for any upcoming clinical or pipeline catalysts that could explain active manager skepticism. The 45-day reporting lag means positions may have already been adjusted further.
Executive Summary
A large institutional cluster in CytomX Therapeutics (CTMX) shows 28 buyers accumulating $26.3M in new positions versus 13 sellers reducing $35.0M, with net selling of $8.7M. The buying is dominated by mega-passive funds (Geode, BofA, Northern Trust) and asset managers (Vanguard, Citigroup), while the selling is concentrated in active quant/asset managers (Millennium, Susquehanna, Marshall Wace) making significant trims or near-exits. The divergence between passive accumulation and active manager reduction suggests a neutral-to-mixed signal with no clear catalyst.
Key Financial Metrics
Institutional Positions
Net institutional flow: -$8.7M
▲ Buyers (28)
| Institution | Action | Change | Position Value | Value Δ |
|---|---|---|---|---|
| Geode | DOUBLED | +126.4% | $17.5M | $7.8M |
| BofA | ADD | +47.8% | $56.6M | $8.6M |
| Northern Trust | DOUBLED | +173.7% | $6.3M | $3.4M |
| Vanguard Portfolio Management | DOUBLED | +120.3% | $6.6M | $2.8M |
▼ Sellers (13)
| Institution | Action | Change | Prev Value | Value Δ |
|---|---|---|---|---|
| Millennium | TRIM | -53.9% | $17.2M | -$10.9M |
| Susquehanna International Group | NEAR_EXIT | -95.2% | $8.8M | -$8.4M |
| Marshall Wace | TRIM | -26.9% | $19.4M | -$8.1M |
Key Facts
- 28 institutional buyers added $26.3M in new positions, bringing total buyer holdings to $98.7M
- 13 institutional sellers reduced $35.0M, with net selling of $8.7M across the cluster
- Top buyers: BofA (+$8.6M), Geode (+$7.8M), Northern Trust (+$3.4M), Vanguard (+$2.8M)
- Top sellers: Millennium (-$10.9M), Susquehanna (-$8.4M), Marshall Wace (-$8.1M)
- Mega-passive funds (Geode, BofA, Northern Trust, JPMorgan) are the primary accumulators
- Active quant/asset managers (Millennium, Susquehanna, Marshall Wace) are the primary sellers
- 13F data reflects Q2 2026 quarter-end positions with 45-day reporting lag
Financial Impact
Aggregate institutional buying of $26.3M vs selling of $35.0M, resulting in net institutional outflow of $8.7M. Top 3 sellers alone account for $27.4M in reductions.
Risk Factors
- 13F data is 45+ days stale; current positions may differ materially
- Active manager selling (Millennium, Susquehanna, Marshall Wace) outweighs passive buying in dollar terms
- No insider buying confluence to corroborate the bullish passive signal
- Small market cap micro-cap biotech with limited liquidity — institutional moves may have outsized impact
Investment Themes
Documents Analyzed
This report is based on 1 institutional 13F filing from SEC EDGAR.
| Document | Accession Number |
|---|---|
| INST-CLUSTER Data (Synthetic) | inst-cluster-CTMX-2026-Q2 |
Track record builds as more directional reports settle.
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Sep 22, 2026 5w ago | Institutional Cluster | $2.94 | awaiting T+60 | — | — |
Jun 22, 2026 18w ago | 8-K | $3.15 $2.77 | ▼ −12.22% | ▼ −15.47% | — |
Mar 17, 2026 31w ago | Press Release | $4.40 $2.98 | ▼ −32.27% | ▼ −43.80% | — |
Mar 16, 2026 32w ago | Press Release | $5.45 $2.98 | ▲ +45.32% | ▲ +55.18% | — |
Mar 16, 2026 32w ago | Press Release | $6.75 $2.94 | ▼ −56.44% | ▼ −66.93% | — |
Mar 4, 2026 33w ago | Press Release | $5.07 $3.71 | ▼ −26.82% | ▼ −36.91% | — |
US Market Status
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