An incredible £16.7m was staked on who would take over from Alain Perrin at Fratton Park – a position filled by Redknapp in December.
English football's governing body is investigating irregular betting patterns in the build-up to Redknapp's return to Fratton Park.
Redknapp, Pompey chairman Milan Mandaric and chief executive Peter Storrie have all been questioned by the FA.
All three insist they had no part in underhand betting.
The FA is continuing to analyse information provided by on-line betting exchange Betfair about the betting that took place on the Pompey job.
But they refused to give an anticipated time-scale for the completion of their findings.
FA spokesman Andrin Cooper said: 'The investigation into allegations of insider betting is ongoing. It is not targeted at any individual.
'There are certain steps that have to be gone through.
'We have an agreement with Betfair who provide us with information on betting patterns.
'It is a matter of collecting all the necessary evidence, then seeing if any disciplinary action needs to be taken.
'The investigation will be finished when it's finished.'
During his meeting at FA headquarters in London's Soho Square in April, Redknapp was shown a list of names of people who had placed bets on him being re-appointed Pompey manager.
The 59-year-old insists he has done nothing wrong and had not placed a bet on himself.
If investigators find evidence they believe shows a breach of betting rules, they will issue a disciplinary charge and the matter will be put before the FA's disciplinary commission.
Anyone deemed to be breaching FA rules faces being fined or suspended from football.