---
schema_version: "secwatch.filing_event.v1"
accession: "0000943374-23-000508"
form_type: "8-K"
ticker: "NBBK"
cik: "0001979330"
company_name: "NB Bancorp, Inc."
filed_at: "2023-12-27T23:59:59+00:00"
generated_at: "2026-06-07T07:08:35.832181+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# NB Bancorp completes IPO, sells 40.9975M shares at $10.00; begins trading on Nasdaq Dec 28 under NBBK

## Summary
- Completed IPO of 40,997,500 shares at $10.00 per share in mutual-to-stock conversion of NB Financial, MHC.
- Common stock begins trading on Nasdaq Capital Market under symbol NBBK on December 28, 2023.
- Contributed 1,708,229 shares and $2.0M cash to Needham Bank Charitable Foundation.
- ESOP intends to purchase up to 3,416,458 shares (8% of outstanding) in the open market.

## SEC filing metadata
- accession: 0000943374-23-000508
- form_type: 8-K
- ticker: NBBK
- cik: 0001979330
- company_name: NB Bancorp, Inc.
- filed_at: 2023-12-27T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1979330/000094337423000508/0000943374-23-000508-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1979330/000094337423000508/form8k_122723.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000943374-23-000508
- JSON: https://secwatch.observer/filing/0000943374-23-000508.json
- Plain text: https://secwatch.observer/filing/0000943374-23-000508.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.