NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK) Institutional Ownership

13F Institutional Holders and Ownership History from Q4 2023 to Q4 2025

Type / Class
Equity / Common Stock, par value $0.01 per share
Symbol
NBBK on Nasdaq
Shares outstanding
45,552,773
Price per share
$19.60
All holders as of 31 Dec 2025
Q4 2025
Total 13F shares
22,268,685
Total reported value
$441,207,411
% of total 13F portfolios
0%
Share change
+3,119,722
Value change
+$62,745,151
Number of holders
161
Price from insider filings
$19.60
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Significant Owners of NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK) based on Schedule 13D/G filings

Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
Needham Bank Employee Stock Ownership Plan Trust 7.5% $67,543,375 3,416,458 Needham Bank Employee Stock Ownership Plan Trust 31 Dec 2025
BlackRock, Inc. 6.7% $47,015,321 2,663,833 BlackRock, Inc. 30 Sep 2025
Pertento Partners LLP 5.1% -2% $41,633,969 +$3,998,788 2,338,987 +11% Pertento Partners LLP 01 Dec 2025
VANGUARD GROUP INC 5% +2.8% $45,606,264 +$6,323,301 2,301,034 +16% The Vanguard Group 31 Dec 2025

As of 31 Dec 2025, 161 institutional investors reported holding 22,268,685 shares of NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK). This represents 49% of the company’s total 45,552,773 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK) together control 39% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
BlackRock, Inc. 6.8% 3,103,770 +10% 0% $61,516,713
Pertento Partners LLP 5.1% 2,343,776 +11% 5.1% $46,453,640
VANGUARD GROUP INC 5.1% 2,301,034 +18% 0% $45,606,494
WELLINGTON MANAGEMENT GROUP LLP 3.2% 1,471,189 -19% 0.01% $29,158,966
STATE STREET CORP 2.4% 1,114,379 -6.9% 0% $22,086,992
GEODE CAPITAL MANAGEMENT, LLC 2.1% 966,662 +10% 0% $19,162,447
HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC 1.5% 701,992 +1% 0.04% $13,913,481
AltraVue Capital, LLC 1.5% 693,000 1.1% $13,735,260
GOLDMAN SACHS GROUP INC 1.3% 593,888 +13% 0% $11,770,865
Tieton Capital Management, LLC 1.2% 524,935 3.6% $10,404,000
FMR LLC 0.84% 383,212 +18% 0% $7,595,263
Nuveen, LLC 0.76% 346,779 +219% 0% $6,873,159
CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.72% 329,398 +15% 0% $6,528,668
NORTHERN TRUST CORP 0.71% 324,313 +4.7% 0% $6,427,883
DIMENSIONAL FUND ADVISORS LP 0.63% 288,028 0% $5,708,814
ALLIANCEBERNSTEIN L.P. 0.56% 254,219 +524% 0% $5,038,621
TWO SIGMA INVESTMENTS, LP 0.56% 252,845 +23% 0.01% $5,011,388
MARSHALL WACE, LLP 0.55% 251,512 -9.2% 0% $4,984,968
RENAISSANCE TECHNOLOGIES LLC 0.55% 251,274 +127% 0.01% $4,980,251
MORGAN STANLEY 0.53% 242,132 +98% 0% $4,799,057
AMERICAN CENTURY COMPANIES INC 0.49% 221,855 +62% 0% $4,397,166
BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.42% 193,150 +68% 0.08% $3,828,233
HENNESSY ADVISORS INC 0.4% 181,000 -2.2% 0.13% $3,587,420
EJF Capital LP 0.38% 174,979 +1.3% 2% $3,468,084
Legato Capital Management LLC 0.38% 171,361 0.29% $3,396,375

Institutional Holders of NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2025 Q4 22,268,685 $441,207,411 +$62,745,151 $19.82 161
2025 Q3 19,191,470 $338,803,226 +$8,507,888 $17.65 144
2025 Q2 18,717,578 $334,367,604 +$6,692,709 $17.86 129
2025 Q1 18,345,847 $331,321,498 +$4,235,296 $18.07 120
2024 Q4 18,099,643 $326,677,743 -$12,909,221 $18.06 113
2024 Q3 18,798,787 $348,790,411 +$34,867,490 $18.56 106
2024 Q2 16,756,519 $253,194,867 +$107,038,595 $15.08 91
2024 Q1 9,585,291 $131,014,856 +$95,658,320 $13.66 55
2023 Q4 2,575,613 $34,675,619 +$30,437,121 $13.45 17