Who owns NB Bancorp, Inc. Common Stock (NBBK)
Which tracked institutional funds hold NBBK, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See NBBK 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
31 tracked funds added or opened NBBK while 28 trimmed or exited it between 2026-Q1 and 2026-Q2 — 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
NBBK’s largest tracked holder by dollar value, BlackRock, 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 NBBK more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in NBBK 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 156 tracked filers holding NBBK, 79 increased or opened the position and 81 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases.
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 NBBK 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 3
- MARSHALL WACE, LLP$3M
- Y-Intercept (Hong Kong) Ltd$1M
- Trexquant Investment LP$979K
Full exits 12
- WELLINGTON MANAGEMENT GROUP LLP$15M
- Tieton Capital Management, LLC$12M
- OP Asset Management Ltd$1M
- JANE STREET GROUP, LLC$1M
- LAZARD ASSET MANAGEMENT LLC$1M
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$1M
Largest adds
- AltraVue Capital, LLC$7M
- BlackRock, Inc.$5M
- DIMENSIONAL FUND ADVISORS LP$5M
- STATE STREET CORP$4M
- CITADEL ADVISORS LLC$4M
- Legato Capital Management LLC$2M
Largest trims
- Pertento Partners LLP$15M
- SEI INVESTMENTS CO$3M
- RENAISSANCE TECHNOLOGIES LLC$3M
- GOLDMAN SACHS GROUP INC$2M
- TWO SIGMA INVESTMENTS, LP$2M
- MILLENNIUM MANAGEMENT LLC$2M
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 3,331,544 | $70M | 15.4% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC trimmed | 1,670,835 | $35M | 7.7% | 2026-Q2 |
| AltraVue Capital, LLC added | 1,655,108 | $35M | 7.6% | 2026-Q2 |
| Pertento Partners LLP trimmed | 1,475,770 | $31M | 6.8% | 2026-Q2 |
| STATE STREET CORP added | 1,471,766 | $31M | 6.8% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,153,217 | $24M | 5.3% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP added | 753,320 | $16M | 3.5% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC trimmed | 571,954 | $12M | 2.6% | 2026-Q2 |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC added | 501,172 | $11M | 2.3% | 2026-Q2 |
| Nuveen, LLC added | 498,869 | $11M | 2.3% | 2026-Q2 |
| FMR LLC added | 497,305 | $11M | 2.3% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC added | 397,046 | $8M | 1.8% | 2026-Q2 |
| Legato Capital Management LLC added | 366,090 | $8M | 1.7% | 2026-Q2 |
| NORTHERN TRUST CORP added | 360,492 | $8M | 1.7% | 2026-Q2 |
| NEW YORK STATE COMMON RETIREMENT FUND added | 346,155 | $7M | 1.6% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 318,612 | $7M | 1.5% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 289,814 | $6M | 1.3% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP trimmed | 277,027 | $6M | 1.3% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC trimmed | 261,866 | $6M | 1.2% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO trimmed | 253,951 | $5M | 1.2% | 2026-Q2 |
| MORGAN STANLEY trimmed | 229,194 | $5M | 1.1% | 2026-Q2 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC added | 221,399 | $5M | 1.0% | 2026-Q2 |
| Empowered Funds, LLC added | 181,399 | $4M | 0.8% | 2026-Q2 |
| HENNESSY ADVISORS INC trimmed | 178,000 | $4M | 0.8% | 2026-Q2 |
| Bank of New York Mellon Corp added | 171,541 | $4M | 0.8% | 2026-Q2 |
| D. E. Shaw & Co., Inc. added | 149,931 | $3M | 0.7% | 2026-Q2 |
| SEI INVESTMENTS CO trimmed | 142,346 | $3M | 0.7% | 2026-Q2 |
| FIRST TRUST ADVISORS LP added | 142,253 | $3M | 0.7% | 2026-Q2 |
| UBS Group AG added | 140,405 | $3M | 0.6% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 131,440 | $3M | 0.6% | 2026-Q2 |
| INTERNATIONAL ASSETS INVESTMENT MANAGEMENT, LLC | 131,013 | $3M | 0.6% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. | 130,219 | $3M | 0.6% | 2026-Q2 |
| PANAGORA ASSET MANAGEMENT INC trimmed | 129,355 | $3M | 0.6% | 2026-Q2 |
| Qube Research & Technologies Ltd trimmed | 127,236 | $3M | 0.6% | 2026-Q2 |
| Financial Engines Advisors L.L.C. added | 126,788 | $3M | 0.6% | 2026-Q2 |
| MARSHALL WACE, LLP trimmed | 123,112 | $3M | 0.6% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 116,349 | $2M | 0.5% | 2026-Q2 |
| MANGROVE PARTNERS IM, LLC | 111,356 | $2M | 0.5% | 2026-Q2 |
| Invesco Ltd. trimmed | 97,941 | $2M | 0.5% | 2026-Q2 |
| Oppenheimer & Close, LLC | 82,999 | $2M | 0.4% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC trimmed | 81,447 | $2M | 0.4% | 2026-Q2 |
| Integrated Wealth Concepts LLC added | 78,691 | $2M | 0.4% | 2026-Q2 |
| Swiss National Bank | 77,100 | $2M | 0.4% | 2026-Q2 |
| CREDIT AGRICOLE S A | 70,000 | $1M | 0.3% | 2026-Q2 |
| MACKENZIE FINANCIAL CORP added | 67,441 | $1M | 0.3% | 2026-Q2 |
| Creative Planning trimmed | 67,320 | $1M | 0.3% | 2026-Q2 |
| Round Rock Advisors LLC added | 66,530 | $1M | 0.3% | 2026-Q2 |
| Focus Partners Wealth trimmed | 65,728 | $1M | 0.3% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 62,478 | $1M | 0.3% | 2026-Q2 |
| PRINCIPAL FINANCIAL GROUP INC added | 59,231 | $1M | 0.3% | 2026-Q2 |
| Legal & General Group Plc added | 56,718 | $1M | 0.3% | 2026-Q2 |
| Y-Intercept (Hong Kong) Ltd added | 54,541 | $1M | 0.3% | 2026-Q2 |
| RHUMBLINE ADVISERS trimmed | 52,690 | $1M | 0.2% | 2026-Q2 |
| LYNCH & ASSOCIATES/IN trimmed | 50,334 | $1M | 0.2% | 2026-Q2 |
| STILWELL VALUE LLC trimmed | 50,000 | $1M | 0.2% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ trimmed | 48,905 | $1M | 0.2% | 2026-Q2 |
| NIXON PEABODY TRUST CO | 48,516 | $1M | 0.2% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC added | 46,899 | $991K | 0.2% | 2026-Q2 |
| CITIGROUP INC added | 46,580 | $984K | 0.2% | 2026-Q2 |
| Trexquant Investment LP trimmed | 46,312 | $979K | 0.2% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 46,016 | $973K | 0.2% | 2026-Q2 |
| FEDERATED HERMES, INC. added | 44,967 | $950K | 0.2% | 2026-Q2 |
| Quantinno Capital Management LP added | 44,137 | $933K | 0.2% | 2026-Q2 |
| WEDGE CAPITAL MANAGEMENT L L P/NC added | 43,216 | $913K | 0.2% | 2026-Q2 |
| Mariner, LLC trimmed | 42,471 | $897K | 0.2% | 2026-Q2 |
| XTX Topco Ltd added | 41,912 | $886K | 0.2% | 2026-Q2 |
| DEUTSCHE BANK AG\ added | 41,024 | $867K | 0.2% | 2026-Q2 |
| EJF Capital LP trimmed | 40,751 | $861K | 0.2% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 39,017 | $824K | 0.2% | 2026-Q2 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC trimmed | 38,359 | $811K | 0.2% | 2026-Q2 |
| Aviance Capital Partners, LLC added | 38,173 | $807K | 0.2% | 2026-Q2 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 38,169 | $807K | 0.2% | 2026-Q2 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed | 35,981 | $760K | 0.2% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 35,185 | $743K | 0.2% | 2026-Q2 |
| Bleakley Financial Group, LLC added | 34,272 | $724K | 0.2% | 2026-Q2 |
| RAFFLES ASSOCIATES LP added | 31,874 | $673K | 0.1% | 2026-Q2 |
| Allspring Global Investments Holdings, LLC added | 30,429 | $658K | 0.1% | 2026-Q2 |
| RAYMOND JAMES FINANCIAL INC added | 29,914 | $632K | 0.1% | 2026-Q2 |
| FRANKLIN RESOURCES INC added | 28,370 | $599K | 0.1% | 2026-Q2 |
| LPL Financial LLC added | 26,409 | $558K | 0.1% | 2026-Q2 |
| Rafferty Asset Management, LLC trimmed | 25,529 | $539K | 0.1% | 2026-Q2 |
| NORTHEAST INVESTMENT MANAGEMENT | 25,000 | $528K | 0.1% | 2026-Q2 |
| Vanguard Global Advisers, LLC added | 24,444 | $517K | 0.1% | 2026-Q2 |
| MetLife Investment Management, LLC added | 24,072 | $509K | 0.1% | 2026-Q2 |
| BARCLAYS PLC added | 23,951 | $506K | 0.1% | 2026-Q2 |
| VANGUARD ASSET MANAGEMENT, Ltd | 23,484 | $496K | 0.1% | 2026-Q2 |
| Russell Investments Group, Ltd. added | 21,332 | $451K | 0.1% | 2026-Q2 |
| MIRABELLA FINANCIAL SERVICES LLP new | 20,227 | $427K | 0.1% | 2026-Q2 |
| Investment Advisory Group, LLC | 20,000 | $423K | 0.1% | 2026-Q2 |
| &PARTNERS | 19,730 | $417K | 0.1% | 2026-Q2 |
| COMMONWEALTH EQUITY SERVICES, LLC trimmed | 19,285 | $407K | 0.1% | 2026-Q2 |
| JPMORGAN CHASE & CO trimmed | 19,283 | $409K | 0.1% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 18,740 | $396K | 0.1% | 2026-Q2 |
| Harbor Advisors LLC added | 17,500 | $370K | 0.1% | 2026-Q2 |
| MERCER GLOBAL ADVISORS INC /ADV added | 16,992 | $359K | 0.1% | 2026-Q2 |
| Zurcher Kantonalbank (Zurich Cantonalbank) | 16,976 | $359K | 0.1% | 2026-Q2 |
| KESTRA PRIVATE WEALTH SERVICES, LLC trimmed | 16,766 | $354K | 0.1% | 2026-Q2 |
| ROCKLAND TRUST CO | 15,969 | $337K | 0.1% | 2026-Q2 |
| Cerity Partners LLC trimmed | 15,558 | $329K | 0.1% | 2026-Q2 |
| ExodusPoint Capital Management, LP added | 15,487 | $327K | 0.1% | 2026-Q2 |
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.