Credit union · NCUA insured
Mass Bay Credit Union
A $367.7M credit union headquartered in South Boston, MA, with 17,688 members and 4 branches in Massachusetts. Best rates: CDs 4.44% and savings 0.35% APY.
Mass Bay Credit Union Carrot Score
79
Carrot Score
Higher than 49% of U.S. banks and credit unions
#63 of 141 in Boston, MA-NH metroHow the score works →
Deposits are federally insured by the NCUA up to $250,000 per depositor.
About Mass Bay Credit Union
Founded in 1936 as a Boston credit union, Mass Bay Credit Union is a member-owned, not-for-profit financial institution.
Originally established for MBTA employees, it later expanded to serve the local community as Mass Bay Credit Union.
The credit union operates branches in South Boston, Quincy, Everett, and Seaport.
- Headquarters
- 147 W 4th St, South Boston, MA 02127
- NCUA charter
- 68137
Membership
Who can join
This may be incomplete or out of date, so check with the credit union before you apply.
Where you live or work
- Membership is open to anyone who lives, works, attends a school, college, or university, or belongs to a labor organization located within Norfolk County, Suffolk County, Middlesex County, Abington, Brockton, Hanover, Hingham, Lynn, Marshfield, Norwell, Peabody, Rockland, Saugus, Scituate, or Whitman.
Employers and groups
- Membership is open to employees or former employees of Keolis.
- Membership is open to employees or former employees of entities affiliated with MassDOT.
- Membership is open to employees of entities who are members of labor unions affiliated with MassDOT.
- Membership is open to employees or former employees of MBTA.
Military, government and schools
- Membership is open to employees or former employees of the Massachusetts State Police.
1 more way to join
Family and household
- Membership is open to immediate family members of eligible members.
Branches
4 branches in Massachusetts
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Massachusetts
4 branches
- South BostonMain office147 W 4th St, South Boston, MA 02127Directions
- Everett183 Main St, Everett, MA 02149Directions
- Quincy Center1250 Hancock St, Quincy, MA 02169Directions
- Seaport Branch409 D Street, South Boston, MA 02127Directions
Walk-in offices from the NCUA directory as of March 31, 2026. Directions open Google Maps. A nearby branch doesn’t mean you can join or open an account.
Financial details
Well capitalizedas reported to the NCUA
| Measure | This credit union | Peers’ middle | Strongest quarter |
|---|---|---|---|
| CapitalNet worth ratio | 11.46% | 11.43% | 13.58% or more |
| Troubled loans60+ days late | 0.89% | 0.68% | 0.39% or less |
| ProfitabilityReturn on assets | 0.59% | 0.75% | 1.18% or more |
| LendingLoans per $100 deposited | $117 | $76 | — |
- CapitalNet worth ratio11.46%Peers’ middle 11.43% · Top 25% 13.58%+
- Troubled loans60+ days late0.89%Peers’ middle 0.68% · Top 25% ≤0.39%
- ProfitabilityReturn on assets0.59%Peers’ middle 0.75% · Top 25% 1.18%+
- LendingLoans per $100 deposited$117Peers’ middle $76
Compared with the 1,338 credit unions with $100 million to $1 billion in assets. The strongest quarter is what the best 25% of them reach: more capital and profit, fewer troubled loans. Lending has no better end.Troubled loans are loans 60 or more days late.
Regulators’ own ratings of Mass Bay Credit Union are confidential. These figures are what it reports to the NCUA each quarter, set beside its peers; they aren’t a rating.