Blakestad, founded in 1974, provides property casualty insurance to private businesses and individuals, focusing on high-net-worth people.
All Blakestad employees, including president Jerod Blakestad, will continue working from the Minneapolis office, according to an announcement by Marsh.
Marsh is a subsidiary of Marsh & McLennan Cos., a publicly traded global professional services company. Last year the corporation posted $13.2 billion in revenue and $1.76 billion in net income, according to its annual financial statement.
The terms of the Blakestad deal were not disclosed.
The corporation has been on a buying spree. It acquired 15 companies in 2016 for $901 million, according to its annual Securities and Exchange Commission filing. In 2015, it acquired 21 companies for $1.2 billion.