Middlesex Savings Bank is a Massachusetts bank headquartered in Natick, Massachusetts, and founded in 1835. It is the largest mutual bank in Massachusetts with more than $5.7 billion in assets and 32 branches in the western Boston suburbs. History The Middlesex Institution for Savings was founded on March 4, 1835 in Concord, Massachusetts. Natick Five Cents Savings Bank was founded in 1859. Medway Savings Bank was founded in 1871. References External links 1835 establishments in Massachusetts Banks based in Massachusetts Mutual savings banks in the United States Banks established in 1835