Who owns Similarweb (SMWB)
Which tracked institutional funds hold SMWB, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See SMWB company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 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 SMWB is one-sided between 2026-Q1 and 2026-Q2: 33 added or opened and 11 trimmed or exited — on balance accumulating.
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
SMWB’s largest tracked holder by dollar value, NASPERS LTD, sizes it at 81.2% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 81.2pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in SMWB 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 2026-Q1 and 2026-Q2, across 67 tracked filers holding SMWB, 35 increased or opened the position and 49 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases. A multi-insider buy cluster also fired inside the quarter.
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 SMWB between the 2026-Q1 and 2026-Q2 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 6
- Viola Growth Management Fund 2 Ltd.$66M
- Lotus Technology Management, LP$3M
- ANTIPODES PARTNERS Ltd$893K
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$848K
- MYDA Advisors LLC$613K
- State of Wyoming$542K
Full exits 6
- Viola Ventures V.C. Management 4 Ltd.$28M
- MIRABELLA FINANCIAL SERVICES LLP$2M
- ACADIAN ASSET MANAGEMENT LLC$1M
- Penn Capital Management Company, LLC$941K
- Militia Capital Management LLC$616K
- Phoenix Financial Ltd.$566K
Largest adds
- NASPERS LTD$39M
- WELLINGTON MANAGEMENT GROUP LLP$15M
- MENORA MIVTACHIM HOLDINGS LTD.$14M
- ION Crossover Partners Ltd$11M
- Ulysses Management LLC$10M
- Schonfeld Strategic Advisors LLC$7M
Largest trims
- MILLENNIUM MANAGEMENT LLC$2M
- Y.D. More Investments Ltd$1M
- MARSHALL WACE, LLP$1M
- Qube Research & Technologies Ltd$891K
- XTX Topco Ltd$531K
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 |
|---|---|---|---|---|
| NASPERS LTD | 11,173,265 | $68M | 17.7% | 2026-Q2 |
| Viola Growth Management Fund 2 Ltd. new | 10,810,778 | $66M | 17.1% | 2026-Q2 |
| MENORA MIVTACHIM HOLDINGS LTD. | 4,015,494 | $25M | 6.4% | 2026-Q2 |
| WELLINGTON MANAGEMENT GROUP LLP added | 3,624,685 | $22M | 5.7% | 2026-Q2 |
| ION Crossover Partners Ltd | 3,030,826 | $19M | 4.8% | 2026-Q2 |
| Ulysses Management LLC trimmed | 2,928,474 | $18M | 4.6% | 2026-Q2 |
| S SQUARED TECHNOLOGY, LLC added | 1,690,000 | $10M | 2.7% | 2026-Q2 |
| Schonfeld Strategic Advisors LLC added | 1,210,629 | $7M | 1.9% | 2026-Q2 |
| Y.D. More Investments Ltd trimmed | 1,147,035 | $7M | 1.8% | 2026-Q2 |
| ARK Investment Management LLC added | 834,663 | $5M | 1.3% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 713,728 | $4M | 1.1% | 2026-Q2 |
| CDC Financial, Inc. added | 674,233 | $4M | 1.1% | 2026-Q2 |
| Alpha Family Trust | 658,935 | $4M | 1.0% | 2026-Q2 |
| NANO CAP NEW MILLENNIUM GROWTH FUND L P added | 650,000 | $4M | 1.0% | 2026-Q2 |
| HERALD INVESTMENT MANAGEMENT Ltd | 645,465 | $4M | 1.0% | 2026-Q2 |
| P.A.W. CAPITAL CORP added | 640,000 | $4M | 1.0% | 2026-Q2 |
| Sphera Management Technology Funds Ltd | 615,000 | $4M | 1.0% | 2026-Q2 |
| CenterBook Partners LP trimmed | 599,737 | $4M | 0.9% | 2026-Q2 |
| Lotus Technology Management, LP new | 531,409 | $3M | 0.9% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 513,277 | $3M | 0.8% | 2026-Q2 |
| PEAK6 LLC added | 484,822 | $3M | 0.8% | 2026-Q2 |
| Connor, Clark & Lunn Investment Management Ltd. trimmed | 445,691 | $3M | 0.7% | 2026-Q2 |
| UBS Group AG added | 403,328 | $2M | 0.6% | 2026-Q2 |
| CITADEL ADVISORS LLC trimmed | 346,735 | $2M | 0.5% | 2026-Q2 |
| MORGAN STANLEY trimmed | 268,203 | $2M | 0.4% | 2026-Q2 |
| LAVELLE CAPITAL LP | 202,727 | $1M | 0.3% | 2026-Q2 |
| Persistent Asset Partners Ltd | 180,000 | $1M | 0.3% | 2026-Q2 |
| SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC added | 169,885 | $1M | 0.3% | 2026-Q2 |
| D. E. Shaw & Co., Inc. added | 159,935 | $980K | 0.3% | 2026-Q2 |
| ANTIPODES PARTNERS Ltd added | 145,601 | $893K | 0.2% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 138,417 | $848K | 0.2% | 2026-Q2 |
| BlackRock, Inc. added | 133,533 | $819K | 0.2% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 129,851 | $796K | 0.2% | 2026-Q2 |
| MYDA Advisors LLC new | 100,000 | $613K | 0.2% | 2026-Q2 |
| Pathstone Holdings, LLC added | 99,390 | $609K | 0.2% | 2026-Q2 |
| State of Wyoming added | 88,458 | $542K | 0.1% | 2026-Q2 |
| STATE STREET CORP trimmed | 77,054 | $472K | 0.1% | 2026-Q2 |
| Quadrature Capital Ltd trimmed | 68,207 | $418K | 0.1% | 2026-Q2 |
| MARSHALL WACE, LLP trimmed | 60,981 | $374K | 0.1% | 2026-Q2 |
| Centiva Capital, LP trimmed | 45,919 | $281K | 0.1% | 2026-Q2 |
| WealthTrust Axiom LLC new | 44,565 | $273K | 0.1% | 2026-Q2 |
| IMC-Chicago, LLC new | 37,506 | $230K | 0.1% | 2026-Q2 |
| SIMPLEX TRADING, LLC added | 33,066 | $203K | 0.1% | 2026-Q2 |
| Qube Research & Technologies Ltd trimmed | 31,847 | $195K | 0.1% | 2026-Q2 |
| LAZARD ASSET MANAGEMENT LLC added | 23,566 | $144K | 0.0% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC trimmed | 18,198 | $112K | 0.0% | 2026-Q2 |
| Integrated Wealth Concepts LLC new | 15,000 | $92K | 0.0% | 2026-Q2 |
| R Squared Ltd new | 11,256 | $69K | 0.0% | 2026-Q2 |
| XTX Topco Ltd trimmed | 10,906 | $67K | 0.0% | 2026-Q2 |
| PRELUDE CAPITAL MANAGEMENT, LLC new | 10,411 | $64K | 0.0% | 2026-Q2 |
| PharVision Advisers, LLC trimmed | 10,368 | $64K | 0.0% | 2026-Q2 |
| Olympiad Research LP new | 10,337 | $63K | 0.0% | 2026-Q2 |
| Cresset Asset Management, LLC | 10,144 | $62K | 0.0% | 2026-Q2 |
| MARATHON CAPITAL MANAGEMENT new | 10,000 | $61K | 0.0% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 9,200 | $56K | 0.0% | 2026-Q2 |
| CITIGROUP INC trimmed | 7,511 | $46K | 0.0% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 5,900 | $36K | 0.0% | 2026-Q2 |
| SBI Securities Co., Ltd. | 1,024 | $6K | 0.0% | 2026-Q2 |
| BARCLAYS PLC trimmed | 690 | $4K | 0.0% | 2026-Q2 |
| Tower Research Capital LLC (TRC) trimmed | 399 | $2K | 0.0% | 2026-Q2 |
| OSAIC HOLDINGS, INC. | 300 | $2K | 0.0% | 2026-Q2 |
| Quarry LP trimmed | 149 | $913 | 0.0% | 2026-Q2 |
| JONES FINANCIAL COMPANIES LLLP | 100 | $560 | 0.0% | 2026-Q2 |
| Smartleaf Asset Management LLC | 29 | $179 | 0.0% | 2026-Q2 |
| Caitong International Asset Management Co., Ltd trimmed | 11 | $67 | 0.0% | 2026-Q2 |
| FMR LLC | 6 | $37 | 0.0% | 2026-Q2 |
| Farther Finance Advisors, LLC trimmed | 3 | $16 | 0.0% | 2026-Q2 |
| MIRABELLA FINANCIAL SERVICES LLP new | 792,664 | $2M | 0.5% | 2026-Q1 stale (1 quarter behind) |
| ACADIAN ASSET MANAGEMENT LLC added | 405,607 | $1M | 0.3% | 2026-Q1 stale (1 quarter behind) |
| Penn Capital Management Company, LLC trimmed | 360,366 | $941K | 0.2% | 2026-Q1 stale (1 quarter behind) |
| Militia Capital Management LLC new | 236,000 | $616K | 0.2% | 2026-Q1 stale (1 quarter behind) |
| Phoenix Financial Ltd. trimmed | 216,904 | $566K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| JPMORGAN CHASE & CO added | 175,207 | $435K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| GSA CAPITAL PARTNERS LLP added | 152,105 | $397K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Jump Financial, LLC added | 147,616 | $385K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Migdal Insurance & Financial Holdings Ltd. | 3,106,157 | $23M | 6.0% | 2025-Q4 stale (2 quarters behind) |
| Nuveen, LLC added | 1,520,398 | $11M | 2.9% | 2025-Q4 stale (2 quarters behind) |
| First Eagle Investment Management, LLC added | 645,647 | $5M | 1.2% | 2025-Q4 stale (2 quarters behind) |
| ROYCE & ASSOCIATES LP added | 537,406 | $4M | 1.0% | 2025-Q4 stale (2 quarters behind) |
| Portolan Capital Management, LLC trimmed | 492,861 | $4M | 1.0% | 2025-Q4 stale (2 quarters behind) |
| GROUP ONE TRADING LLC added | 147,063 | $1M | 0.3% | 2025-Q4 stale (2 quarters behind) |
| AMERIPRISE FINANCIAL INC trimmed | 138,422 | $1M | 0.3% | 2025-Q4 stale (2 quarters behind) |
| Numerai GP LLC added | 117,949 | $883K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| Trexquant Investment LP trimmed | 108,038 | $809K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| Swiss National Bank | 87,474 | $655K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| NORTHERN TRUST CORP added | 80,549 | $603K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| SEI INVESTMENTS CO added | 76,702 | $574K | 0.1% | 2025-Q4 stale (2 quarters behind) |
| BLAIR WILLIAM & CO/IL trimmed | 71,044 | $532K | 0.1% | 2025-Q4 stale (2 quarters behind) |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO added | 60,419 | $453K | 0.1% | 2025-Q4 stale (2 quarters behind) |
| Legal & General Group Plc added | 56,620 | $424K | 0.1% | 2025-Q4 stale (2 quarters behind) |
| SCALAR GAUGE MANAGEMENT, LLC trimmed | 441,742 | $4M | 1.1% | 2025-Q3 stale (3 quarters behind) |
| ESSEX INVESTMENT MANAGEMENT CO LLC added | 380,793 | $4M | 0.9% | 2025-Q3 stale (3 quarters behind) |
| CEERA INVESTMENTS, LLC | 319,027 | $3M | 0.8% | 2025-Q3 stale (3 quarters behind) |
| Legato Capital Management LLC added | 109,711 | $1M | 0.3% | 2025-Q3 stale (3 quarters behind) |
| WOLVERINE TRADING, LLC new | 56,143 | $539K | 0.1% | 2025-Q3 stale (3 quarters behind) |
| Cubist Systematic Strategies, LLC trimmed | 50,413 | $469K | 0.1% | 2025-Q3 stale (3 quarters behind) |
| Y-Intercept (Hong Kong) Ltd added | 117,831 | $924K | 0.2% | 2025-Q2 stale (4 quarters behind) |
| FORMULA GROWTH LTD new | 100,000 | $784K | 0.2% | 2025-Q2 stale (4 quarters behind) |
| Hood River Capital Management LLC added | 78,446 | $615K | 0.2% | 2025-Q2 stale (4 quarters behind) |
1 parent filing withheld from the table above, and from the coverage figures, to avoid listing one book twice: Viola Ventures V.C. Management 4 Ltd. (last filed 2026-Q1, 10,810,778 shares) reconciles to its 1 current affiliate (10,810,778 shares) — 0.000% apart.
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.