Who owns PROK (PROK)
Which tracked institutional funds hold PROK, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See PROK company fundamentals →
Ownership as of the 2026-Q1 13F filings. 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
The tracked-fund tape on PROK is one-sided between 2025-Q4 and 2026-Q1: 3 added or opened and 17 trimmed or exited — on balance reducing.
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
PROK’s largest tracked holder by dollar value, SUVRETTA CAPITAL MANAGEMENT, LLC, sizes it at 0.6% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.6pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in PROK 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 70 tracked filers holding PROK, 36 increased or opened the position and 31 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
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 PROK 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 2
- VANGUARD CAPITAL MANAGEMENT LLC$2M
- VANGUARD FIDUCIARY TRUST CO$964K
Full exits 2
- VANGUARD GROUP INC$4M
- CITADEL ADVISORS LLC$833K
Largest adds
- MARSHALL WACE, LLP$439K
Largest trims
- SUVRETTA CAPITAL MANAGEMENT, LLC$6M
- MORGAN STANLEY$4M
- Bleichroeder LP$900K
- Artia Global Partners LP$884K
- GOLDMAN SACHS GROUP INC$771K
- BlackRock, Inc.$662K
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 |
|---|---|---|---|---|
| SUVRETTA CAPITAL MANAGEMENT, LLC | 12,341,266 | $22M | 26.1% | 2026-Q1 |
| MORGAN STANLEY added | 8,955,967 | $16M | 18.9% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 2,271,577 | $4M | 4.8% | 2026-Q1 |
| Bleichroeder LP | 2,000,000 | $4M | 4.2% | 2026-Q1 |
| Artia Global Partners LP trimmed | 1,806,939 | $3M | 3.8% | 2026-Q1 |
| Hennion & Walsh Asset Management, Inc. added | 1,611,693 | $3M | 3.4% | 2026-Q1 |
| BlackRock, Inc. trimmed | 1,387,116 | $2M | 2.9% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 1,250,794 | $2M | 2.6% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,230,409 | $2M | 2.6% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,146,937 | $2M | 2.4% | 2026-Q1 |
| MARSHALL WACE, LLP added | 1,011,744 | $2M | 2.1% | 2026-Q1 |
| Brown University | 1,000,000 | $2M | 2.1% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 753,412 | $1M | 1.6% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 627,771 | $1M | 1.3% | 2026-Q1 |
| STATE STREET CORP added | 556,845 | $997K | 1.2% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 538,371 | $964K | 1.1% | 2026-Q1 |
| Woodline Partners LP | 500,000 | $895K | 1.1% | 2026-Q1 |
| MYDA Advisors LLC trimmed | 428,775 | $768K | 0.9% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 421,902 | $755K | 0.9% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 346,382 | $620K | 0.7% | 2026-Q1 |
| UBS Group AG trimmed | 334,546 | $599K | 0.7% | 2026-Q1 |
| Amundi added | 291,708 | $522K | 0.6% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 264,285 | $473K | 0.6% | 2026-Q1 |
| ExodusPoint Capital Management, LP added | 254,353 | $455K | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP | 241,580 | $432K | 0.5% | 2026-Q1 |
| Squarepoint Ops LLC trimmed | 211,107 | $378K | 0.4% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 204,488 | $366K | 0.4% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP added | 203,226 | $364K | 0.4% | 2026-Q1 |
| BARCLAYS PLC trimmed | 146,284 | $262K | 0.3% | 2026-Q1 |
| Virtus Investment Advisers, LLC added | 123,388 | $221K | 0.3% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 118,981 | $212K | 0.3% | 2026-Q1 |
| Voleon Capital Management LP new | 102,698 | $184K | 0.2% | 2026-Q1 |
| Susquehanna Portfolio Strategies, LLC trimmed | 97,378 | $174K | 0.2% | 2026-Q1 |
| EntryPoint Capital, LLC added | 82,862 | $148K | 0.2% | 2026-Q1 |
| OMERS ADMINISTRATION Corp trimmed | 67,900 | $122K | 0.1% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 65,578 | $117K | 0.1% | 2026-Q1 |
| Brevan Howard Capital Management LP new | 64,153 | $115K | 0.1% | 2026-Q1 |
| Hudson Bay Capital Management LP added | 62,084 | $111K | 0.1% | 2026-Q1 |
| Jain Global LLC trimmed | 51,305 | $92K | 0.1% | 2026-Q1 |
| CITIGROUP INC trimmed | 49,384 | $88K | 0.1% | 2026-Q1 |
| Diametric Capital, LP new | 47,827 | $86K | 0.1% | 2026-Q1 |
| Catalyst Funds Management Pty Ltd trimmed | 47,800 | $86K | 0.1% | 2026-Q1 |
| Jefferies Financial Group Inc. trimmed | 46,398 | $83K | 0.1% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 34,074 | $61K | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC added | 32,845 | $59K | 0.1% | 2026-Q1 |
| Virtus Family Office LLC | 27,500 | $49K | 0.1% | 2026-Q1 |
| Tower Research Capital LLC (TRC) added | 20,439 | $37K | 0.0% | 2026-Q1 |
| Jump Financial, LLC trimmed | 18,540 | $33K | 0.0% | 2026-Q1 |
| LETKO, BROSSEAU & ASSOCIATES INC | 15,900 | $28K | 0.0% | 2026-Q1 |
| SummitTX Capital, L.P. new | 14,600 | $26K | 0.0% | 2026-Q1 |
| R Squared Ltd new | 13,696 | $25K | 0.0% | 2026-Q1 |
| CTC Alternative Strategies, Ltd. new | 13,453 | $24K | 0.0% | 2026-Q1 |
| Callan Family Office, LLC | 13,394 | $24K | 0.0% | 2026-Q1 |
| LMR Partners LLP new | 12,484 | $22K | 0.0% | 2026-Q1 |
| PRELUDE CAPITAL MANAGEMENT, LLC new | 12,107 | $22K | 0.0% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 11,828 | $21K | 0.0% | 2026-Q1 |
| Bank of New York Mellon Corp | 11,192 | $20K | 0.0% | 2026-Q1 |
| Caitong International Asset Management Co., Ltd new | 10,992 | $20K | 0.0% | 2026-Q1 |
| FMR LLC trimmed | 10,254 | $18K | 0.0% | 2026-Q1 |
| SIMPLEX TRADING, LLC trimmed | 6,741 | $12K | 0.0% | 2026-Q1 |
| VANGUARD GROUP INC added | 1,648,229 | $4M | 4.4% | 2025-Q4 stale |
| CITADEL ADVISORS LLC added | 371,797 | $833K | 1.0% | 2025-Q4 stale |
| Nuveen, LLC new | 266,366 | $233K | 0.3% | 2025-Q1 stale |
| Y-Intercept (Hong Kong) Ltd new | 351,622 | $208K | 0.2% | 2025-Q2 stale |
| Virtu Financial LLC added | 84,002 | $203K | 0.2% | 2025-Q3 stale |
| AQR CAPITAL MANAGEMENT LLC added | 198,338 | $117K | 0.1% | 2025-Q2 stale |
| Lighthouse Investment Partners, LLC new | 48,060 | $108K | 0.1% | 2025-Q4 stale |
| Cubist Systematic Strategies, LLC added | 176,452 | $104K | 0.1% | 2025-Q2 stale |
| ALPS ADVISORS INC trimmed | 95,182 | $83K | 0.1% | 2025-Q1 stale |
| DEUTSCHE BANK AG\ added | 86,337 | $76K | 0.1% | 2025-Q1 stale |
| INTECH INVESTMENT MANAGEMENT LLC added | 85,026 | $74K | 0.1% | 2025-Q1 stale |
| ALLIANCEBERNSTEIN L.P. | 84,230 | $74K | 0.1% | 2025-Q1 stale |
| RHUMBLINE ADVISERS added | 83,369 | $73K | 0.1% | 2025-Q1 stale |
| GROUP ONE TRADING LLC added | 28,021 | $63K | 0.1% | 2025-Q4 stale |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 66,786 | $59K | 0.1% | 2025-Q1 stale |
| Corebridge Financial, Inc. added | 54,535 | $48K | 0.1% | 2025-Q1 stale |
| Point72 Asia (Singapore) Pte. Ltd. new | 66,281 | $39K | 0.0% | 2025-Q2 stale |
| SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC trimmed | 44,707 | $39K | 0.0% | 2025-Q1 stale |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 43,108 | $38K | 0.0% | 2025-Q1 stale |
| SG Americas Securities, LLC added | 61,870 | $37K | 0.0% | 2025-Q2 stale |
| SEI INVESTMENTS CO trimmed | 41,042 | $36K | 0.0% | 2025-Q1 stale |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE added | 38,798 | $34K | 0.0% | 2025-Q1 stale |
| Invesco Ltd. added | 32,258 | $28K | 0.0% | 2025-Q1 stale |
| Zullo Investment Group, Inc. trimmed | 11,620 | $28K | 0.0% | 2025-Q3 stale |
| Cetera Investment Advisers new | 12,288 | $28K | 0.0% | 2025-Q4 stale |
| VOYA INVESTMENT MANAGEMENT LLC trimmed | 30,125 | $26K | 0.0% | 2025-Q1 stale |
| Engineers Gate Manager LP trimmed | 10,452 | $25K | 0.0% | 2025-Q3 stale |
| TWO SIGMA ADVISERS, LP new | 10,900 | $24K | 0.0% | 2025-Q4 stale |
| Police & Firemen's Retirement System of New Jersey | 26,533 | $23K | 0.0% | 2025-Q1 stale |
| NINE MASTS CAPITAL Ltd new | 10,244 | $23K | 0.0% | 2025-Q4 stale |
| CIBC WORLD MARKETS CORP added | 24,700 | $22K | 0.0% | 2025-Q1 stale |
| ProShare Advisors LLC trimmed | 24,099 | $21K | 0.0% | 2025-Q1 stale |
| NEW YORK STATE COMMON RETIREMENT FUND | 17,179 | $15K | 0.0% | 2025-Q1 stale |
| IEQ CAPITAL, LLC new | 23,051 | $14K | 0.0% | 2025-Q2 stale |
| HSBC HOLDINGS PLC added | 12,893 | $11K | 0.0% | 2025-Q1 stale |
| AMERIPRISE FINANCIAL INC added | 11,388 | $10K | 0.0% | 2025-Q1 stale |
| Legal & General Group Plc | 10,925 | $10K | 0.0% | 2025-Q1 stale |
| Vanguard Personalized Indexing Management, LLC trimmed | 10,616 | $9K | 0.0% | 2025-Q1 stale |
| Ameritas Investment Partners, Inc. | 10,523 | $9K | 0.0% | 2025-Q1 stale |
| BALYASNY ASSET MANAGEMENT L.P. added | 14,683 | $9K | 0.0% | 2025-Q2 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.