The divergence between a few large accumulators (Assenagon, Parnassus) and multiple near-exits (Vontobel, Ninety One UK) creates an unusual signal. Monitor upcoming Q4 2026 13F filings to see if the selling trend continues or reverses — a sustained outflow from active managers would be a negative read-through for BSX's near-term price support.
Executive Summary
A mixed institutional cluster in BSX for Q3 2026 shows 6 buyers adding $140.1M in new positions (led by Assenagon's $115.8M add) against 5 sellers reducing by $368.5M (led by Vontobel's $182.3M near-exit and Ninety One UK's $148.7M near-exit). The net selling pressure of $228.4M from active managers suggests a bearish tilt, though the buying side is concentrated and material.
Key Financial Metrics
Institutional Positions
Net institutional flow: -$228.4M
▲ Buyers (6)
| Institution | Action | Change | Position Value | Value Δ |
|---|---|---|---|---|
| Assenagon Asset Management | ADD | +61.4% | $294.0M | $115.8M |
| Parnassus Investments | ADD | +29.3% | $66.3M | $16.2M |
| Wealth Enhancement Advisory Services | ADD | +55.4% | $15.2M | $4.6M |
▼ Sellers (5)
| Institution | Action | Change | Prev Value | Value Δ |
|---|---|---|---|---|
| Vontobel Holding | NEAR_EXIT | -87.9% | $207.9M | -$182.3M |
| Ninety One Uk | NEAR_EXIT | -99.5% | $149.5M | -$148.7M |
| Banque Pictet & Cie | TRIM | -65% | $45.6M | -$29.3M |
Key Facts
- 6 buyers added $140.1M in new BSX positions; 5 sellers reduced by $368.5M
- Largest buyer: Assenagon Asset Management added $115.8M (61.4% increase to $294.0M)
- Largest seller: Vontobel Holding near-exited $182.3M (87.9% reduction to $25.6M)
- Ninety One UK near-exited $148.7M (99.5% reduction to $771K)
- Net institutional outflow of $228.4M in Q3 2026
- All participants are active asset managers — no passive/index fund activity detected
Financial Impact
Net institutional outflow of $228.4M in Q3 2026, with $140.1M in buying vs $368.5M in selling
Risk Factors
- 13F data is 45+ days stale; the cluster may have already been unwound or reversed
- Net selling by active managers could indicate deteriorating fundamentals not yet priced
- Concentrated buying by Assenagon may be a temporary tactical position, not a long-term vote of confidence
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-BSX-2026-Q3 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Oct 23, 2026 4d ago | Institutional Cluster | $45.69 $45.58 | ▲ +0.24% | ▲ +0.95% | — |
Oct 7, 2026 20d ago | 8-K | $41.58 $42.04 | ▲ +1.11% | ▲ +1.53% | — |
Sep 23, 2026 4w ago | 8-K | $44.62 $44.68 | ▼ −0.13% | ▼ −0.22% | — |
Aug 31, 2026 8w ago | Court Ruling | $48.08 $48.37 | ▲ +0.60% | ▲ +0.16% | — |
Aug 26, 2026 8w ago | 8-K | $48.17 $46.67 | ▲ +3.11% | ▲ +3.77% | — |
Aug 22, 2026 9w ago | Institutional Cluster | $49.01 $49.86 | ▲ +1.73% | ▲ +1.41% | — |
Aug 7, 2026 11w ago | Insider Cluster | $50.46 $51.19 | ▲ +1.45% | ▲ +1.77% | — |
Aug 7, 2026 11w ago | Insider Cluster | $50.46 $51.19 | ▲ +1.45% | ▲ +1.77% | — |
Aug 5, 2026 11w ago | Insider Cluster | $49.30 $49.31 | ▲ +0.02% | ▼ −0.59% | — |
Jul 29, 2026 12w ago | 8-K | $46.04 $46.00 | ▲ +0.09% | ▲ +1.76% | — |
US Market Status
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