State Bank & Trust, based in North Dakota, will buy Bell Mortgage, a Minnesota-based mortgage company founded in 1880. The acquisition will combine the largest independent bank in Minnesota, North and South Dakota with the tri-state area’s largest private mortgage company. Since Bell Mortgage was founded, it has funded more than 500,000 home mortgages. In the last decade the total dollar amount in originations reached $10 billion. State Bank & Trust has more than $1.9 billion in assets. Bell Mortgage CEO Gary Kirt said both companies have done well during tough times, and State Bank & Trust President Michael Solberg said the bank will now offer home equity loans, construction loans and other home mortgage services. “We hope to bring additional resources to help them continue to grow with the high level of service they’re already providing,” Solberg said. Write to Jon Prior.