Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in IOSP held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 3.9M | $283.2M | +5.9% | 15.748% | 0.00% |
| 2 | Allspring Global Investments Holdings, LLC | 2.3M | $170.5M | -1.7% | 9.402% | 0.29% |
| 3 | VANGUARD PORTFOLIO MANAGEMENT LLC | 1.9M | $135.8M | — | 7.552% | 0.01% |
| 4 | DIMENSIONAL FUND ADVISORS LP | 1.2M | $90.7M | +5.7% | 5.043% | 0.02% |
| 5 | VANGUARD CAPITAL MANAGEMENT LLC | 1.1M | $81.4M | — | 4.525% | 0.00% |
| 6 | STATE STREET CORP | 964K | $70.4M | +1.6% | 3.915% | 0.00% |
| 7 | VICTORY CAPITAL MANAGEMENT INC | 865K | $63.2M | -9.0% | 3.512% | 0.04% |
| 8 | Nuveen, LLC | 643K | $47.0M | +28.0% | 2.611% | 0.01% |
| 9 | GEODE CAPITAL MANAGEMENT, LLC | 631K | $46.1M | +3.5% | 2.560% | 0.00% |
| 10 | TWO SIGMA INVESTMENTS, LP | 593K | $43.3M | +271.8% | 2.408% | 0.04% |
| 11 | UBS Group AG | 566K | $41.3M | +298.4% | 2.298% | 0.01% |
| 12 | GOLDMAN SACHS GROUP INC | 492K | $35.9M | +1.5% | 1.998% | 0.00% |
| 13 | Assenagon Asset Management S.A. | 491K | $35.8M | +175.5% | 1.993% | 0.06% |
| 14 | Qube Research & Technologies Ltd | 407K | $29.7M | +26.9% | 1.651% | 0.03% |
| 15 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 366K | $26.7M | -2.1% | 1.485% | 0.00% |
| 16 | AQR CAPITAL MANAGEMENT LLC | 312K | $22.8M | +16.4% | 1.267% | 0.01% |
| 17 | BROWN ADVISORY INC | 296K | $21.6M | -3.1% | 1.204% | 0.04% |
| 18 | GENDELL JEFFREY L | 295K | $21.5M | +3.2% | 1.196% | 0.29% |
| 19 | BANK OF AMERICA CORP /DE/ | 291K | $21.2M | -9.8% | 1.180% | 0.00% |
| 20 | D. E. Shaw & Co., Inc. | 287K | $20.9M | -7.5% | 1.164% | 0.02% |
| 21 | NORTHERN TRUST CORP | 284K | $20.8M | +3.5% | 1.154% | 0.00% |
| 22 | ROYCE & ASSOCIATES LP | 261K | $19.1M | -14.4% | 1.061% | 0.19% |
| 23 | MORGAN STANLEY | 236K | $17.2M | -3.3% | 0.956% | 0.00% |
| 24 | Western Standard LLC | 227K | $16.6M | -15.5% | 0.921% | 8.71% |
| 25 | CITADEL ADVISORS LLC | 221K | $16.1M | +203.8% | 0.897% | 0.01% |
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 IOSP — a direct measure of their conviction.
Filings activity in IOSP 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 | 260 | +1.2% | 82.33% | 3.86 pp | $1.76B | 4.5% |
| Q4 2025 | 257 | 1.2% | 86.19% | +0.38 pp | $1.84B | +0.4% |
| Q3 2025 | 260 | +1.2% | 85.81% | 7.58 pp | $1.83B | 8.1% |
| Q2 2025 | 257 | 4.1% | 93.39% | 12.50 pp | $1.99B | 12% |
| Q1 2025 | 268 | +5.1% | 105.89% | 15.85 pp | $2.26B | 13% |
| Q4 2024 | 255 | 0.8% | 121.74% | 2.13 pp | $2.60B | 1.7% |
| Q3 2024 | 257 | 3.4% | 123.87% | 49.85 pp | $2.64B | 29% |
| Q2 2024 | 266 | — | 173.72% | — | $3.71B | — |
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 IOSP stock.
Based on Q1 2026 13F filings, institutional ownership of Innospec Inc. stands at 82.3%, held across 260 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of IOSP, with approximately 3,878,975 shares worth $0.28B as of Q1 2026.
Yes — 2 widely-followed marquee investors appear among the top 25 institutional holders of IOSP, including TWO SIGMA INVESTMENTS, LP, CITADEL ADVISORS LLC.
Our composite Smart Money Score for IOSP is 46 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
41 institutions opened new positions in IOSP during Q1 2026, while 38 fully exited. 95 added to existing positions and 124 trimmed.
IOSP institutional ownership fell by 3.86 percentage points quarter-over-quarter, with a net change of +3 holders.
The top 10 institutions account for 58.7% of all reported 13F value in IOSP, and the top 25 account for 79.7%.
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.
Innospec Inc. (IOSP) Institutional Ownership