Both businesses are based in Douglas on the Isle of Man.
All IFS employees have been offered contracts with MAC Financial other than its co-founders and directors.
The acquisition has been given the go ahead by the regulator and is expected to complete by the start of next month.
MAC Financial offers Financial Planning, protection and employee benefits to private and corporate clients. It was established in 2004 following a management buyout from Aon Financial Services by the Group CEO Jon McGowan. MAC Financial is part of the MAC Group.
Mr McGowan said that negotiating the acquisition in the current difficult circumstances was an achievement and a credit to the MAC team and formed part of a planned growth strategy.
The MAC Group also said that it has a number of discussions underway regarding further acquisitions.
Jon McGowan, CEO of MAC Group, said: “MAC is constantly looking at strategic opportunities to grow our successful financial services business”
“IFS has built up a significant number of long-established clients who have similar needs to our own and we look forward to welcoming them, along with our new colleagues, into the MAC family.”