Latest Period
Q1 2026
Security Snapshot
NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK) Institutional Ownership
CUSIP: 63945M107
13F Institutional Holders and Ownership History from Q4 2023 to Q1 2026
Institutions Reporting
176
Shares (Excl. Options)
23,080,458
Price
$21.07
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- Security type / class
- Equity / Common Stock, par value $0.01 per share
- Symbol
- NBBK on Nasdaq
- All holders as of 31 Mar 2026
- Q1 2026
- Total 13F shares
- 23,080,458
- Total 13F value
- $486,184,309
- Portfolio coverage rank
- 0%
- Share change
- +754,160
- Value change
- +$16,858,165
- Number of holders
- 176
- Shares outstanding
- 44,556,826
- SEC-reported price per share
- $20.03
- Insider filing price
- $20.03
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
3 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- NBBK - NB Bancorp, Inc. - Common Stock, par value $0.01 per share is tracked under CUSIP 63945M107.
- 176 institutions reported positions in Q1 2026.
- 3 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 163 to 176 between Q4 2025 and Q1 2026.
- SEC-reported value moved from $441,285,654 to $486,184,309.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 176 institutions filings for Q1 2026.
Security key
63945M107
Latest holder period
Q1 2026
13F holders
176
13D/G owners
3
CIK / CUSIP context first
Open Q1 2026 holders
NBBK full holder history
NB Bancorp, Inc. SEC filings
NB Bancorp, Inc. company facts
NB Bancorp, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 63945M107:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
3
Security
NBBK
| 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 | 4.6% | -10% | $43,185,367 | -$6,097,089 | 2,049,614 | -12% | Pertento Partners LLP | 31 Mar 2026 |
As of 31 Mar 2026, 176 institutional investors reported holding 23,080,458 shares of NB Bancorp, Inc. - Common Stock, par value $0.01 per share (NBBK). This represents 52% of the company’s total 44,556,826 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
41%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| BlackRock, Inc. | 6.9% | 3,084,222 | -0.63% | 0% | $64,984,549 |
| Pertento Partners LLP | 5% | 2,206,666 | -5.8% | 4.9% | $46,494,453 |
| VANGUARD CAPITAL MANAGEMENT LLC | 3.8% | 1,703,928 | 0% | 0% | $35,901,763 |
| AltraVue Capital, LLC | 2.9% | 1,304,080 | +88% | 2.4% | $27,476,966 |
| STATE STREET CORP | 2.9% | 1,293,538 | +16% | 0% | $27,254,846 |
| GEODE CAPITAL MANAGEMENT, LLC | 2.5% | 1,098,930 | +14% | 0% | $23,159,188 |
| WELLINGTON MANAGEMENT GROUP LLP | 1.6% | 710,000 | -52% | 0% | $14,959,700 |
| GOLDMAN SACHS GROUP INC | 1.6% | 691,668 | +16% | 0% | $14,573,447 |
| Tieton Capital Management, LLC | 1.2% | 553,570 | +5.5% | 3.9% | $11,664,000 |
| DIMENSIONAL FUND ADVISORS LP | 1.2% | 522,384 | +81% | 0% | $11,005,796 |
| Nuveen, LLC | 1.1% | 488,033 | +41% | 0% | $10,282,856 |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC | 1% | 450,772 | -36% | 0.03% | $9,497,766 |
| FMR LLC | 0.98% | 437,725 | +14% | 0% | $9,222,866 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 0.87% | 386,132 | 0% | 0% | $8,135,801 |
| TWO SIGMA INVESTMENTS, LP | 0.83% | 371,807 | +47% | 0.01% | $7,833,973 |
| NORTHERN TRUST CORP | 0.75% | 335,360 | +3.4% | 0% | $7,066,034 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.71% | 318,365 | -3.3% | 0% | $6,707,951 |
| SEI INVESTMENTS CO | 0.68% | 302,181 | +110% | 0.01% | $6,366,955 |
| MORGAN STANLEY | 0.63% | 279,870 | +16% | 0% | $5,896,862 |
| Legato Capital Management LLC | 0.62% | 276,070 | +61% | 0.53% | $5,816,795 |
| RENAISSANCE TECHNOLOGIES LLC | 0.59% | 263,906 | +5% | 0.01% | $5,560,499 |
| AMERICAN CENTURY COMPANIES INC | 0.59% | 263,656 | +19% | 0% | $5,555,232 |
| NEW YORK STATE COMMON RETIREMENT FUND | 0.58% | 260,585 | +80% | 0.01% | $5,490,526 |
| VANGUARD FIDUCIARY TRUST CO | 0.57% | 254,038 | 0% | 0% | $5,352,581 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 0.47% | 208,394 | +7.9% | 0.09% | $4,390,862 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
10
Latest
Q1 2026
Rows shown
1-10 of 10
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q1 | 23,080,458 | $486,184,309 | +$16,858,165 | $21.07 | 176 |
| 2025 Q4 | 22,272,633 | $441,285,654 | +$62,746,915 | $19.82 | 163 |
| 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 |