Main Street Bank
Marlborough, Massachusetts, Middlesex County
$1.7B in total assets, the 695th largest of 4,309 US banks and 33rd of 95 headquartered in Massachusetts.
- FDIC certificate
- 90235
- Established
- 1860
- Owned by
- Main Street Group Bancshares Mhc
- Primary regulator
- FDIC
- Website
- www.bankmainstreet.com
At a glance
Compared with 46 banks headquartered in Massachusetts with $1 billion to $10 billion in assets, as of June 30, 2026.
| Measure | This bank | Percentile | Peer range, middle 90% | Peer median |
|---|---|---|---|---|
| Total assets | $1.7B | 39% | $2.0B | |
| Loans | $1.3B | 30% | $1.5B | |
| Deposits | $1.4B | 44% | $1.7B | |
| Return on assets | 0.62% | 33% | 0.72% | |
| Net interest margin | 3.01% | 48% | 3.04% | |
| Efficiency ratio | 73.4% | 63% | 69.7% | |
| Equity to assets | 11.03% | 52% | 10.84% | |
| Loans to deposits | 90% | 16% | 100% |
Growth
Total assets grew 5.1% a year over the last 5 years and 12.2% a year over 10 years, including 1 acquisition in the last 10 years.
Acquisitions
| Closed | Acquired bank | Assets at acquisition |
|---|---|---|
| Apr 2017 | North Middlesex Savings Bank Ayer, MA | $446M |
Where they operate
6 branches in 2 counties.
Largest markets by deposits
| County | Deposits | Market share | Rank |
|---|---|---|---|
| Middlesex County, MA | $1.2B | 1.5% | 19 of 42 |
| Worcester County, MA | $180M | 0.8% | 22 of 26 |
Deposits by branch from the FDIC Summary of Deposits, June 2026. Rank among all banks with branches in that county.
Branch history since 2016
No net change since 2016 (6 branches then and now). 1 opened, 7 acquired, 8 closed or sold.
| Period | What happened | Opened or acquired | Closed or sold | Net change | Branches at end |
|---|---|---|---|---|---|
| Start of 2016 | Starting point | 6 | |||
| 2016 | Opened Hudson | 1 | 0 | +1 | 7 |
| 2017 | Acquired North Middlesex Savings Bank | 7 | 0 | +7 | 14 |
| 2018 | Closed Devens | 0 | 1 | −1 | 13 |
| 2020 | Closed Westborough | 0 | 1 | −1 | 12 |
| 2021 | Closed Groton and Shirley | 0 | 2 | −2 | 10 |
| 2024 | Closed 4 in Massachusetts | 0 | 4 | −4 | 6 |
Balance sheet and earnings
Loans by type
| Type | Share | This bank | Peers |
|---|---|---|---|
| 1-4 family residential | 56% | 46% | |
| Commercial real estate | 26% | 26% | |
| Business (C&I) | 7% | 8% | |
| Construction and land | 6% | 7% | |
| Multifamily | 4% | 10% | |
| Consumer | 1% | 2% | |
| Other | 0% | 1% |
Deposits by type
| Type | Share | This bank | Peers |
|---|---|---|---|
| Other interest-bearing | 63% | 52% | |
| Time deposits | 19% | 32% | |
| Noninterest-bearing | 18% | 16% |
Brokered deposits are 7.7% of deposits (peers 3.7%).
Return on assets
Trailing four quarters, with the peer median.
Credit and capital
| This bank | Peer median | |
|---|---|---|
| Noncurrent loans | 1.69% | 0.58% |
| Net charge-offs, annualized | -0.02% | 0.01% |
| Reserves to loans | 0.90% | 0.84% |
| Leverage ratio | 12.04% | 11.15% |
Noncurrent loans exclude government-guaranteed portions.
Related banks
Similar size in Massachusetts
Largest competitors in Middlesex County, MA
Figures as of June 30, 2026 from the bank's Call Report, FDIC structure and branch data, and the Federal Reserve. Short link: bankingstats.com/banks/main-street-bank-marlborough-ma