AXA took a 39% shareholding in broker Layton Blackham in a deal that converted its former holding of non-voting preference shares into voting shares.
Chief executive Chris Blackham and other directors hold the balance, with Blackham holding the voting rights.
He said AXA would have a say in "strategic" matters but would not have a say in the placing of risks.
"They will have no involvement in where we place business or how we place business," he said.
"It's a financial deal and does not affect the insurance broking business."
Layton Blackham would stick to its "open marketing philosophy" and would not give preferential treatment to AXA.
The only extra access which AXA would have, above that given to other key suppliers, was to the broker's annual general meeting which AXA would attend in a financial capacity.
Blackham said: "The deal gives us and our customers the financial security of having one of the world's biggest companies as an institutional investor."
The broker's plans focused on selective acquisitions, sales growth and the establishment of its partnership and franchise solutions programme.
Blackham said he would pick 12 brokers from a list of about 40 to become founding partners and develop their businesses together.
The company's next acquisition would be completed at the end of January.