Who owns Innospec Inc. (IOSP)
Which tracked institutional funds hold IOSP, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See IOSP company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
61 tracked funds added or opened IOSP while 63 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
IOSP’s largest tracked holder by dollar value, VANGUARD GROUP INC, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes IOSP more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in IOSP divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 265 tracked filers holding IOSP, 150 increased or opened the position and 119 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in IOSP between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 17
- VANGUARD PORTFOLIO MANAGEMENT LLC$136M
- VANGUARD CAPITAL MANAGEMENT LLC$81M
- VANGUARD FIDUCIARY TRUST CO$12M
- DEPRINCE RACE & ZOLLO INC$5M
- Penn Capital Management Company, LLC$2M
- Centiva Capital, LP$2M
Full exits 17
- VANGUARD GROUP INC$224M
- WESTWOOD HOLDINGS GROUP INC$38M
- Medina Value Partners, LLC$29M
- TWO SIGMA ADVISERS, LP$12M
- Walleye Capital LLC$8M
- AlphaQuest LLC$3M
Largest adds
- TWO SIGMA INVESTMENTS, LP$31M
- UBS Group AG$30M
- Assenagon Asset Management S.A.$22M
- CITADEL ADVISORS LLC$11M
- Nuveen, LLC$9M
- ACADIAN ASSET MANAGEMENT LLC$8M
Largest trims
- BlackRock, Inc.$90M
- MILLENNIUM MANAGEMENT LLC$36M
- VICTORY CAPITAL MANAGEMENT INC$10M
- Allspring Global Investments Holdings, LLC$9M
- ROYCE & ASSOCIATES LP$4M
- Western Standard LLC$4M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. trimmed | 2,605,126 | $190M | 9.2% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC trimmed | 2,315,942 | $170M | 8.3% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 1,860,091 | $136M | 6.6% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 1,242,089 | $91M | 4.4% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,114,598 | $81M | 3.9% | 2026-Q1 |
| STATE STREET CORP added | 964,335 | $70M | 3.4% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 864,994 | $63M | 3.1% | 2026-Q1 |
| Nuveen, LLC added | 643,248 | $47M | 2.3% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 630,592 | $46M | 2.2% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 593,039 | $43M | 2.1% | 2026-Q1 |
| UBS Group AG added | 565,911 | $41M | 2.0% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 492,011 | $36M | 1.7% | 2026-Q1 |
| Assenagon Asset Management S.A. added | 490,884 | $36M | 1.7% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 426,050 | $31M | 1.5% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 406,624 | $30M | 1.4% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 365,874 | $27M | 1.3% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 308,284 | $23M | 1.1% | 2026-Q1 |
| BROWN ADVISORY INC trimmed | 296,465 | $22M | 1.0% | 2026-Q1 |
| GENDELL JEFFREY L added | 294,504 | $22M | 1.0% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ trimmed | 290,766 | $21M | 1.0% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 286,794 | $21M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 284,239 | $21M | 1.0% | 2026-Q1 |
| ROYCE & ASSOCIATES LP trimmed | 261,336 | $19M | 0.9% | 2026-Q1 |
| MORGAN STANLEY trimmed | 235,571 | $17M | 0.8% | 2026-Q1 |
| Western Standard LLC trimmed | 226,833 | $17M | 0.8% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 220,883 | $16M | 0.8% | 2026-Q1 |
| SEI INVESTMENTS CO added | 174,121 | $13M | 0.6% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 166,794 | $12M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 160,752 | $12M | 0.6% | 2026-Q1 |
| FIRST WILSHIRE SECURITIES MANAGEMENT INC added | 148,072 | $11M | 0.5% | 2026-Q1 |
| NORGES BANK trimmed | 105,689 | $10M | 0.5% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC trimmed | 133,272 | $10M | 0.5% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 131,291 | $10M | 0.5% | 2026-Q1 |
| HRT FINANCIAL LP added | 125,055 | $9M | 0.4% | 2026-Q1 |
| ACADIAN ASSET MANAGEMENT LLC added | 122,552 | $9M | 0.4% | 2026-Q1 |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC trimmed | 120,810 | $9M | 0.4% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 120,477 | $9M | 0.4% | 2026-Q1 |
| PANAGORA ASSET MANAGEMENT INC added | 119,675 | $9M | 0.4% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 118,900 | $9M | 0.4% | 2026-Q1 |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC trimmed | 107,963 | $8M | 0.4% | 2026-Q1 |
| ZWJ INVESTMENT COUNSEL INC added | 103,787 | $8M | 0.4% | 2026-Q1 |
| TEACHER RETIREMENT SYSTEM OF TEXAS added | 103,102 | $8M | 0.4% | 2026-Q1 |
| Invesco Ltd. trimmed | 98,667 | $7M | 0.3% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 94,506 | $7M | 0.3% | 2026-Q1 |
| ProShare Advisors LLC added | 89,841 | $7M | 0.3% | 2026-Q1 |
| Public Sector Pension Investment Board added | 88,694 | $6M | 0.3% | 2026-Q1 |
| MUTUAL OF AMERICA CAPITAL MANAGEMENT LLC trimmed | 87,463 | $6M | 0.3% | 2026-Q1 |
| Trexquant Investment LP added | 78,370 | $6M | 0.3% | 2026-Q1 |
| Numerai GP LLC trimmed | 76,616 | $6M | 0.3% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC trimmed | 74,443 | $5M | 0.3% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 71,607 | $5M | 0.3% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 71,157 | $5M | 0.3% | 2026-Q1 |
| Leeward Investments, LLC - MA trimmed | 69,810 | $5M | 0.2% | 2026-Q1 |
| DEPRINCE RACE & ZOLLO INC new | 68,029 | $5M | 0.2% | 2026-Q1 |
| Engineers Gate Manager LP added | 64,682 | $5M | 0.2% | 2026-Q1 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND trimmed | 61,669 | $5M | 0.2% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 61,427 | $4M | 0.2% | 2026-Q1 |
| SG Americas Securities, LLC trimmed | 60,868 | $4M | 0.2% | 2026-Q1 |
| Legal & General Group Plc trimmed | 59,120 | $4M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 56,535 | $4M | 0.2% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC added | 55,234 | $4M | 0.2% | 2026-Q1 |
| FMR LLC added | 51,805 | $4M | 0.2% | 2026-Q1 |
| Swiss National Bank | 49,003 | $4M | 0.2% | 2026-Q1 |
| INTECH INVESTMENT MANAGEMENT LLC trimmed | 44,967 | $3M | 0.2% | 2026-Q1 |
| Atom Investors LP added | 40,771 | $3M | 0.1% | 2026-Q1 |
| IEQ CAPITAL, LLC added | 39,960 | $3M | 0.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 37,967 | $3M | 0.1% | 2026-Q1 |
| Creative Planning trimmed | 37,635 | $3M | 0.1% | 2026-Q1 |
| XTX Topco Ltd added | 36,292 | $3M | 0.1% | 2026-Q1 |
| PDT Partners, LLC trimmed | 34,576 | $3M | 0.1% | 2026-Q1 |
| Edgestream Partners, L.P. trimmed | 34,226 | $2M | 0.1% | 2026-Q1 |
| MARSHALL WACE, LLP added | 33,526 | $2M | 0.1% | 2026-Q1 |
| FRANKLIN RESOURCES INC added | 33,485 | $2M | 0.1% | 2026-Q1 |
| Y-Intercept (Hong Kong) Ltd added | 33,296 | $2M | 0.1% | 2026-Q1 |
| Penn Capital Management Company, LLC new | 33,286 | $2M | 0.1% | 2026-Q1 |
| CONNORS INVESTOR SERVICES INC added | 33,095 | $2M | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 31,826 | $2M | 0.1% | 2026-Q1 |
| INGALLS & SNYDER LLC | 28,927 | $2M | 0.1% | 2026-Q1 |
| State of New Jersey Common Pension Fund D trimmed | 28,227 | $2M | 0.1% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. trimmed | 26,509 | $2M | 0.1% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 27,529 | $2M | 0.1% | 2026-Q1 |
| Moran Wealth Management, LLC trimmed | 27,031 | $2M | 0.1% | 2026-Q1 |
| Holocene Advisors, LP added | 26,473 | $2M | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC added | 26,250 | $2M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 2,926,874 | $224M | 10.9% | 2025-Q4 stale |
| WASATCH ADVISORS LP trimmed | 528,144 | $50M | 2.4% | 2025-Q1 stale |
| WESTWOOD HOLDINGS GROUP INC added | 491,451 | $38M | 1.8% | 2025-Q4 stale |
| Medina Value Partners, LLC added | 378,769 | $29M | 1.4% | 2025-Q4 stale |
| Financial Harvest, LLC new | 433,843 | $13M | 0.6% | 2025-Q1 stale |
| TWO SIGMA ADVISERS, LP added | 159,200 | $12M | 0.6% | 2025-Q4 stale |
| Cubist Systematic Strategies, LLC trimmed | 154,165 | $12M | 0.6% | 2025-Q3 stale |
| SEGALL BRYANT & HAMILL, LLC added | 118,161 | $10M | 0.5% | 2025-Q2 stale |
| Walleye Capital LLC trimmed | 103,935 | $8M | 0.4% | 2025-Q4 stale |
| KIRR MARBACH & CO LLC /IN/ trimmed | 54,335 | $5M | 0.2% | 2025-Q2 stale |
| AlphaQuest LLC trimmed | 42,228 | $3M | 0.2% | 2025-Q4 stale |
| ALGERT GLOBAL LLC trimmed | 34,278 | $3M | 0.1% | 2025-Q4 stale |
| Nebula Research & Development LLC added | 28,128 | $2M | 0.1% | 2025-Q2 stale |
| BAHL & GAYNOR INC added | 27,306 | $2M | 0.1% | 2025-Q3 stale |
| Verition Fund Management LLC trimmed | 26,664 | $2M | 0.1% | 2025-Q4 stale |
| CANADA PENSION PLAN INVESTMENT BOARD | 26,000 | $2M | 0.1% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.