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NB Bancorp, Inc.

NBBK
Exchange
Nasdaq
Industry
Savings Institutions, Not Federally Chartered
SEC CIK
0001979330

In the last 90 days, NB Bancorp, Inc. insiders filed 2 open-market purchases and 1 sale; 161 institutions reported holding it in 13F filings for Q2 2026, worth $474.9M in total; no superinvestor holds it.

13F holders, Q1 2026

Institutional positions in NB Bancorp, Inc. as of Mar 31, 2026. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
177
+15 vs. Q4 2025
Shares held
23.1M
+3.14M (+15.7%) vs. Q4 2025
Total value
$486.3M
+$91.1M (+23.1%) vs. Q4 2025
New holders
32
66 more added
Sold out
17
44 more reduced

2 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q4 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting NBBK on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ1 2026: 177 institutions
Q1 2021: 0 institutionsQ2 2021: 0 institutionsQ3 2021: 0 institutionsQ4 2021: 0 institutionsQ1 2022: 0 institutionsQ2 2022: 0 institutionsQ3 2022: 0 institutionsQ4 2022: 0 institutionsQ1 2023: 0 institutionsQ2 2023: 0 institutionsQ3 2023: 0 institutionsQ4 2023: 17 institutionsQ1 2024: 56 institutionsQ2 2024: 92 institutionsQ3 2024: 108 institutionsQ4 2024: 114 institutionsQ1 2025: 122 institutionsQ2 2025: 132 institutionsQ3 2025: 146 institutionsQ4 2025: 164 institutionsQ1 2026: 177 institutionsQ2 2026: 161 institutions
Value heldQ1 2026: $486.3M
Q1 2021: $0Q2 2021: $0Q3 2021: $0Q4 2021: $0Q1 2022: $0Q2 2022: $0Q3 2022: $0Q4 2022: $0Q1 2023: $0Q2 2023: $0Q3 2023: $0Q4 2023: $34.7MQ1 2024: $131.0MQ2 2024: $253.2MQ3 2024: $355.7MQ4 2024: $326.7MQ1 2025: $331.3MQ2 2025: $334.4MQ3 2025: $338.8MQ4 2025: $441.3MQ1 2026: $486.3MQ2 2026: $474.9M
Institutions holding NBBK and their total value by quarter
QuarterHoldersValue
Q2 2026161$474.9M
Q1 2026177$486.3M
Q4 2025164$441.3M
Q3 2025146$338.8M
Q2 2025132$334.4M
Q1 2025122$331.3M
Q4 2024114$326.7M
Q3 2024108$355.7M
Q2 202492$253.2M
Q1 202456$131.0M
Q4 202317$34.7M
Q3 20230$0
Q2 20230$0
Q1 20230$0
Q4 20220$0
Q3 20220$0
Q2 20220$0
Q1 20220$0
Q4 20210$0
Q3 20210$0
Q2 20210$0
Q1 20210$0

Institutions, Q1 2026

Shares, value and share of portfolio for each institution holding NB Bancorp, Inc.; share changes are against Q4 2025.

Institutions holding NBBK in Q1 2026
InstitutionSharesValue% of portfolioChange in sharesAction
BlackRock, Inc.3,084,222$65.0M0.00%−19,548−0.6%Reduced
Pertento Partners LLP2,206,666$46.5M4.93%−137,110−5.8%Reduced
Vanguard Capital Management LLC1,703,928$35.9M0.00%+1,703,928New
AltraVue Capital, LLC1,304,080$27.5M2.37%+611,080+88.2%Added
State Street Corp1,293,538$27.3M0.00%+179,159+16.1%Added
Geode Capital Management, LLC1,098,930$23.2M0.00%+132,268+13.7%Added
Wellington Management Group LLP710,000$15.0M0.00%−761,189−51.7%Reduced
Goldman Sachs Group Inc691,668$14.6M0.00%+97,780+16.5%Added
Tieton Capital Management, LLC553,570$11.7M3.91%+28,635+5.5%Added
Dimensional Fund Advisors LP522,384$11.0M0.00%+234,356+81.4%Added
Nuveen, LLC488,033$10.3M0.00%+141,254+40.7%Added
Hotchkis & Wiley Capital Management LLC450,772$9.50M0.03%−251,220−35.8%Reduced
FMR LLC437,725$9.22M0.00%+54,513+14.2%Added
Vanguard Portfolio Management LLC386,132$8.14M0.00%+386,132New
Two Sigma Investments, LP371,807$7.83M0.01%+118,962+47.0%Added
Northern Trust Corp335,360$7.07M0.00%+11,047+3.4%Added
Charles Schwab Investment Management Inc318,365$6.71M0.00%−11,033−3.3%Reduced
SEI Investments Co302,181$6.37M0.01%+158,397+110.2%Added
Morgan Stanley279,870$5.90M0.00%+37,738+15.6%Added
Legato Capital Management LLC276,070$5.82M0.53%+104,709+61.1%Added
Renaissance Technologies LLC263,906$5.56M0.01%+12,632+5.0%Added
American Century Companies Inc263,656$5.56M0.00%+41,801+18.8%Added
New York State Common Retirement Fund260,585$5.49M0.01%+116,200+80.5%Added
Vanguard Fiduciary Trust Co254,038$5.35M0.00%+254,038New
Bridgeway Capital Management, LLC208,394$4.39M0.09%+15,244+7.9%Added
Hennessy Advisors Inc180,000$3.79M0.14%−1,000−0.6%Reduced
Qube Research & Technologies Ltd175,066$3.69M0.01%+157,714+908.9%Added
Empowered Funds, LLC168,394$3.55M0.02%+15,244+10.0%Added
Millennium Management LLC158,243$3.33M0.00%+103,377+188.4%Added
Panagora Asset Management Inc150,096$3.16M0.01%−295−0.2%Reduced
Bank of New York Mellon Corp148,066$3.12M0.00%−1,155−0.8%Reduced
First Trust Advisors LP140,264$2.96M0.00%−1,823−1.3%Reduced
International Assets Investment Management, LLC131,013$2.78M0.19%+44,113+50.8%Added
AQR Capital Management LLC128,821$2.71M0.00%+23,810+22.7%Added
Financial Engines Advisors L.L.C.125,723$2.65M0.01%+8,016+6.8%Added
Alliancebernstein L.P.130,219$2.58M0.00%−124,000−48.8%Reduced
Bank of America Corp118,801$2.50M0.00%+28,160+31.1%Added
Citadel Advisors LLC116,371$2.45M0.00%+9,914+9.3%Added
Mangrove Partners111,356$2.35M0.19%00.0%Unchanged
Invesco Ltd.101,244$2.13M0.00%+37,907+59.8%Added
Colony Group, LLC92,809$1.96M0.00%+1,443+1.6%Added
Oppenheimer & Close, LLC82,999$1.75M1.10%00.0%Unchanged
Swiss National Bank77,100$1.62M0.00%00.0%Unchanged
UBS Group AG76,120$1.60M0.00%−69,974−47.9%Reduced
Creative Planning70,906$1.49M0.00%+18,411+35.1%Added
D. E. Shaw & Co., Inc.70,385$1.48M0.00%+24,619+53.8%Added
Credit Agricole S A70,000$1.47M0.00%+70,000New
Round Rock Advisors, LLC66,467$1.40M0.21%+14,561+28.1%Added
Stilwell Value LLC65,000$1.37M0.82%00.0%Unchanged
Jane Street Group, LLC60,669$1.28M0.00%−20,972−25.7%Reduced
OP Asset Management Ltd58,392$1.23M0.01%+58,392New
Lazard Asset Management LLC57,302$1.21M0.00%+5,142+9.9%Added
Principal Financial Group Inc55,364$1.17M0.00%−9,105−14.1%Reduced
Lynch & Associates53,334$1.12M0.21%−1,000−1.8%Reduced
Rhumbline Advisers53,175$1.12M0.00%+964+1.8%Added
Legal & General Group Plc53,008$1.12M0.00%−7,608−12.6%Reduced
BNP Paribas Arbitrage, SA53,005$1.12M0.00%−17,874−25.2%Reduced
Susquehanna International Group, LLP51,593$1.09M0.00%+51,593New
Mackenzie Financial Corp50,897$1.07M0.00%+50,897New
Mariner, LLC49,495$1.04M0.00%+13,129+36.1%Added
Nixon Peabody Trust Co48,516$1.02M0.08%00.0%Unchanged
Integrated Wealth Concepts LLC47,927$1.01M0.01%+331+0.7%Added
Wedge Capital Management L L P42,356$892.4K0.02%+42,356New
Ameriprise Financial Inc41,959$884.1K0.00%−36,641−46.6%Reduced
EJF Capital LLC41,457$873.5K0.62%−133,522−76.3%Reduced
Price T Rowe Associates Inc41,072$866.0K0.00%+1,579+4.0%Added
Arrowstreet Capital, Limited Partnership40,276$848.6K0.00%+21,410+113.5%Added
XTX Topco Ltd39,782$838.2K0.01%+39,782New
UBS Asset Management Americas Inc39,362$829.4K0.00%+170+0.4%Added
Aviance Capital Partners, LLC37,167$783.1K0.09%00.0%Unchanged
Integrated Quantitative Investments LLC37,075$781.2K0.14%−3,869−9.4%Reduced
California State Teachers Retirement System35,797$754.2K0.00%−296−0.8%Reduced
JPMorgan Chase & Co36,088$746.3K0.00%−23,125−39.1%Reduced
Federated Hermes, Inc.33,899$714.3K0.00%−338−1.0%Reduced
Citigroup Inc33,451$704.8K0.00%+10,566+46.2%Added
Connor, Clark & Lunn Investment Management Ltd.32,249$679.5K0.00%+12,490+63.2%Added
Deutsche Bank AG31,106$655.4K0.00%+6,081+24.3%Added
Rafferty Asset Management, LLC29,998$632.1K0.00%+5,802+24.0%Added
Allspring Global Investments Holdings, LLC29,474$626.3K0.00%+29,474New
Susquehanna Fundamental Investments, LLC27,840$586.6K0.02%−1,182−4.1%Reduced
Franklin Resources Inc27,270$574.6K0.00%+27,270New
LPL Financial LLC26,360$555.4K0.00%+2,032+8.4%Added
Quantinno Capital Management LP25,941$546.6K0.00%+2,620+11.2%Added
Los Angeles Capital Management LLC25,375$534.7K0.00%−64,995−71.9%Reduced
Susquehanna Portfolio Strategies, LLC25,370$534.5K0.01%00.0%Unchanged
Four Tree Island Advisory LLC25,011$527.0K0.27%+3,555+16.6%Added
Northeast Investment Management25,000$526.8K0.02%+2,000+8.7%Added
State of Wisconsin Investment Board24,386$513.8K0.00%−2,255−8.5%Reduced
Martingale Asset Management L P23,900$503.6K0.01%+12,200+104.3%Added
Vanguard Global Advisers, LLC23,514$495.4K0.00%+23,514New
Vanguard Asset Management, Ltd23,484$494.8K0.00%+23,484New
Barclays PLC23,099$486.7K0.00%−47,673−67.4%Reduced
MetLife Investment Management22,806$480.5K0.00%−316−1.4%Reduced
Commonwealth Equity Services, LLC22,492$473.9K0.00%+996+4.6%Added
Investment Advisory Group, LLC20,000$421.4K0.11%00.0%Unchanged
Wiley Bros.-Aintree Capital, LLC19,730$415.7K0.00%−100−0.5%Reduced
Mirae Asset Global ETFs Holdings Ltd.18,693$393.9K0.00%+143+0.8%Added
Polymer Capital Management (US) LLC17,866$376.4K0.06%+17,866New
Kestra Private Wealth Services, LLC17,731$373.6K0.00%−1,969−10.0%Reduced
Cerity Partners LLC17,388$366.4K0.00%+17,388New