Branch Network
Main Street Bank Locations & Branches Marlborough, Massachusetts
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Main Street Bank operates 6 branches from its headquarters in Marlborough, MA, .
Main Street Bank branch network
All 6 branches are in MASSACHUSETTS, across 6 cities. Its largest office by deposits is its main office in Marlborough, MA, with $729.6M (52.4% of its branch deposits). It had the same number of branches on June 30, 2025.
Main Street Bank at a glance
Its CET1 capital ratio was 17.31% at Q2 2026, comfortably above the 7% level required once the capital conservation buffer is included.
- Total assets, Q2 2026
- $1.67B
- CET1 ratio, Q2 2026
- 17.31%
- Deposit insurance
- FDIC
- Regulator
- FDIC
- Latest call report
- Q2 2026, FFIEC 051
- Established
- 1860
Full financial profile · Is Main Street Bank safe? · Main Street Bank call report · Routing number
Deposit market share
Share of all FDIC-insured deposits held in each area, from the June 30, 2026 Summary of Deposits. Rank 1 is the largest holder. Shares are by bank charter, not by holding company.
| Area | Rank | Deposit share | Deposits |
|---|---|---|---|
| City: Marlborough, MA (1 branch) | 1 of 8 | 44.7% | $729.6M |
| State: MA (6 branches) | 38 of 112 | 0.2% | $1.39B |
Ranked by total assets among banks headquartered in the state: Largest banks in Massachusetts.
Share by county and metro area
Main Street Bank's share of FDIC-insured deposits in the counties and metro areas where it has branches, from the June 30, 2026 Summary of Deposits. Up to the ten largest of each are shown, by the bank's deposits. Rank 1 is the largest holder. Banks only: credit unions are not in the Summary of Deposits.
Counties
| County | Rank | Deposit share | Deposits | County total |
|---|---|---|---|---|
| Middlesex, MA (4 branches) | 19 of 42 | 1.5% | $1.21B | $83.13B |
| Worcester, MA (2 branches) | 22 of 26 | 0.8% | $180.0M | $22.52B |
Metro areas
| Metro area | Rank | Deposit share | Deposits | Metro total |
|---|---|---|---|---|
| Boston-Cambridge-Newton, MA-NH (4 branches) | 30 of 99 | 0.2% | $1.21B | $580.15B |
| Worcester, MA-CT (2 branches) | 22 of 26 | 0.8% | $180.0M | $22.52B |
| Branch | Location | ZIP | Deposits |
|---|---|---|---|
| Main Street Bank (main office) | Marlborough, MA | 01752 | $729.6M |
| North Middlesex Svgs Br | Ayer, MA | 01432 | $243.6M |
| Pepperell Branch | Pepperell, MA | 01463 | $126.7M |
| Hudson Branch | Hudson, MA | 01749 | $113.6M |
| Northborough Branch | Northborough, MA | 01532 | $91.9M |
| Southborough Branch | Southborough, MA | 01772 | $88.1M |
Source: FDIC Summary of Deposits, June 30, 2026. How the survey works.
Regulator records: FDIC BankFind (cert 90235) · FFIEC NIC profile (RSSD 818401)