"I can't talk too much about the specifics but we've been in discussions with several investors for the last six months I'd say," he told reporters at the season-ending Abu Dhabi Grand Prix.
"We have agreed terms with an investor at the moment and we are still working through that."
Fitzpatrick, who saved the tail-end British-based team from collapse after they went into administration as Marussia in 2014, said he had always accepted that money equalled performance in Formula One and Manor needed it.
"Anything that was going to bring more funding to the team and help the team develop and progress I was very open to and if that meant bringing in another investor, and even a majority investor, that was something I was happy to do," he said.
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Manor chief executive Thomas Mayer said earlier that the talks were for a third party to acquire a majority shareholding in the smallest team on the starting grid.
They were 10th in the championship until the penultimate race in the season in Brazil, where Sauber's Felipe Nasr finished ninth in his home race to allow the Swiss team to overtake.
If Mercedes-powered Manor cannot score again, a big ask for a team whose sole point this year came in Austria in June thanks to German Pascal Wehrlein's 10th place, they stand to lose millions in prize money.
Fitzpatrick said the Brazil result had been a big disappointment, even if the team had made a big step forward.
"Obviously, the way the points are structured, that was a critical race for us, very unexpected," he said. "But that's racing."
No drivers have been confirmed by the team for next season, with French rookie Esteban Ocon leaving for Force India and Wehrlein tipped to switch to Sauber in place of Nasr.
Sauber principal Monisha Kaltenborn said Banco do Brasil, who sponsor the team as part of Nasr's current deal, had served notice they were pulling out at the end of the season due to Brazil's financial crisis.
That leaves Nasr, the only Brazilian driver in the sport after Felipe Massa's retirement, facing an uncertain future.
(Editing by Ed Osmond)
