The service will be held at St Botolph-without-Bishopsgate in Liverpool Street, London, at 11am.
It will then be followed by a reception at Drapers' Hall.
Winterflood's family will also be raising funds for the Royal Trinity Hospice in Clapham, "who provide such wonderful support to so many people", they said.
Winterflood died on 29 June, with a career in financial services spanning several decades, from starting as a messenger for stockbrokers Greener Dreyfus & Co in 1953, to setting up his own bespoke ‘market jobber' business Winterflood Securities in 1988, to being awarded an MBE in 2012 for his services to the financial industry.