Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
291 institutional managers reported holding INSP for the quarter ended Mar 31, 2026. Reported positions total over 95% of shares outstanding; the top 10 hold 65%. 51 opened new positions; 97 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 3.55M | 12.37% | $182.8M | unchanged | 2018 Q2 |
| Vanguard Group | 3.11M | 10.85% | $160.4M | added +5.4% | 2018 Q2 |
| Deerfield Management Company, L.p. | 2.70M | 9.42% | $139.2M | added +79.5% | 2025 Q2 |
| Wellington Management | 2.54M | 8.84% | $130.6M | added +14.7% | 2025 Q4 |
| Morgan Stanley | 1.45M | 5.05% | $74.7M | added +15.2% | 2018 Q2 |
| D. E. Shaw | 1.19M | 4.14% | $61.2M | trimmed -1.9% | 2018 Q3 |
| William Blair Investment Management, LLC | 1.14M | 3.96% | $58.6M | trimmed -2.1% | 2020 Q4 |
| UBS | 1.09M | 3.79% | $56.0M | added +24.4% | 2018 Q2 |
| State Street | 956.0k | 3.33% | $49.2M | added +4.1% | 2018 Q2 |
| Artisan Partners | 780.6k | 2.72% | $40.2M | trimmed -0.7% | 2024 Q1 |
| Braidwell LP | 677.6k | 2.36% | $34.9M | added +25.3% | 2023 Q3 |
| Goldman Sachs | 664.0k | 2.31% | $34.2M | added +133.1% | 2018 Q2 |
| Soleus Capital Management, L.p. | 576.3k | 2.01% | $29.7M | added +92.5% | 2025 Q1 |
| Vestal Point Capital, LP | 539.3k | 1.88% | $27.8M | opened | 2025 Q3 |
| Assenagon Asset Management S.a. | 520.2k | 1.81% | $26.8M | added +96.3% | 2025 Q4 |
| Deutsche Bank AG\ | 513.2k | 1.79% | $26.4M | trimmed -0.7% | 2018 Q2 |
| Geode Capital | 510.2k | 1.78% | $26.3M | added +3.8% | 2018 Q2 |
| Aberdeen Group plc | 477.5k | 1.66% | $24.6M | added +3.6% | 2023 Q4 |
| Renaissance Technologies | 470.0k | 1.64% | $24.2M | added +14.4% | 2019 Q2 |
| Adar1 Capital Management, LLC | 405.2k | 1.41% | $20.9M | added +2601.3% | 2025 Q3 |
| Citadel Advisors | 394.1k | 1.37% | $20.3M | trimmed -22.9% | 2018 Q2 |
| Millennium Management | 386.1k | 1.34% | $19.9M | added +91% | 2020 Q1 |
| Walleye Capital LLC | 358.5k | 1.25% | $18.5M | added +343.6% | 2019 Q4 |
| RA Capital Management, L.p. | 325.7k | 1.14% | $16.8M | added +129.4% | 2025 Q3 |
| BNP Paribas Financial Markets | 320.3k | 1.12% | $16.5M | trimmed -29.6% | 2018 Q2 |
| AQR Capital | 308.7k | 1.07% | $15.9M | added +1041.5% | 2019 Q2 |
| Jefferies Financial Group INC. | 306.4k | 1.07% | $15.8M | unchanged | 2025 Q4 |
| Bamco INC /NY/ | 298.5k | 1.04% | $15.4M | trimmed -11.6% | 2019 Q1 |
| Amundi | 256.8k | 0.90% | $13.2M | trimmed -29.6% | 2021 Q2 |
| Royal Bank OF Canada | 253.0k | 0.88% | $13.0M | added +2203.1% | 2018 Q2 |
| Dimensional Fund Advisors | 234.7k | 0.82% | $12.1M | trimmed -31.3% | 2021 Q1 |
| Susquehanna International Group | 210.6k | 0.73% | $10.8M | added +334.2% | 2019 Q1 |
| Acadian Asset Management | 209.5k | 0.73% | $10.8M | added +794.7% | 2025 Q3 |
| Northern Trust | 197.0k | 0.69% | $10.1M | unchanged | 2018 Q2 |
| Bank OF America CORP /DE/ | 186.1k | 0.65% | $9.6M | trimmed -11.4% | 2018 Q2 |
| Charles Schwab Investment Management | 183.4k | 0.64% | $9.4M | trimmed -5.6% | 2018 Q2 |
| Cerity Partners LLC | 181.4k | 0.63% | $9.3M | opened | 2026 Q1 |
| T. Rowe Price | 181.3k | 0.63% | $9.3M | trimmed -41.2% | 2020 Q3 |
| Bridgewater Associates | 173.5k | 0.60% | $8.9M | added +141.9% | 2021 Q1 |
| Tudor Investment | 167.2k | 0.58% | $8.6M | added +48.1% | 2025 Q4 |
| CPP Investment Board | 164.1k | 0.57% | $8.5M | added +55.5% | 2025 Q1 |
| Champlain Investment Partners, LLC | 159.0k | 0.55% | $8.2M | trimmed -21.7% | 2019 Q3 |
| Y-Intercept (Hong Kong) LTD | 158.3k | 0.55% | $8.2M | added +124.1% | 2024 Q2 |
| Balyasny Asset Management | 151.9k | 0.53% | $7.8M | trimmed -18.9% | 2025 Q3 |
| BNY Mellon | 148.8k | 0.52% | $7.7M | trimmed -31.1% | 2018 Q2 |
| Ameriprise Financial INC | 143.5k | 0.50% | $7.4M | added +57.2% | 2018 Q2 |
| Longaeva Partners L.p. | 138.8k | 0.48% | $7.1M | opened | 2026 Q1 |
| Wasatch Advisors LP | 138.6k | 0.48% | $7.1M | added +19.4% | 2018 Q2 |
| Regal Partners LTD | 135.8k | 0.47% | $7.0M | trimmed -35.7% | 2025 Q3 |
| LOS Angeles Capital Management LLC | 133.0k | 0.46% | $6.8M | added +94193.6% | 2024 Q3 |
Largest 50 of 291 shown; the full ranked, searchable register is at boothcheck.com/holders/INSP. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.