After joining as an assistant general manager in 1982 he was appointed to the board in 1990 and made sales & marketing director before becoming chief executive in 2007.
The society has already started searching for Winter’s replacement.
Winter said: “When I took over as chief executive I said the maximum amount of time anyone should serve as a CEO of any organisation is 10 years.
“I like to think that since April 2007, when I became CEO, the society has achieved a great deal, maintaining a healthy and profitable business in the face of regulatory change, standing up for mortgage misfits, and being true to our role as a mutual.
“There is still work to do however and it will be business as usual before I hang up my boots.”
Sarah Evans, chairman at Ipswich Building Society, said: “Paul will be a hard act to follow but we are confident that launching the search now for our new CEO will allow for a seamless transition, and allow us time to find the right successor.
“We will be celebrating Paul’s achievements over 35 years with the Society when the time comes for him to leave us. For now there is a full programme ahead and Paul is very much committed to helping the society move forward.”
