HBRIC CEO Andrew Newman said the investor would be "dealt with in the public domain when they, and we, are ready".
Yesterday HBRC interim chief executive Liz Lambert said there had been no confirmation of the investor.
"That's in the hands of HBRIC at this stage, they're working with the investor and as soon as they have reached full terms and conditions they will be bringing that information back to council and that's the point that it'll become public," she added.
Ms Lambert said the council was "almost there" in deciding to invest in the dam - referring to their July 8 agreement that three of the four conditions precedent had been met before investment could proceed - the one outstanding decision being the investor.
"That is the type of process that will be negotiated between HBRIC and the investor right up until the last minute," she said, "As soon as they have that negotiation complete [council will] know about it and it'll go public."
When asked if ACC was the investor, HBRC chairman Fenton Wilson said "I'm ever hopeful", but he had heard nothing to that effect.
"I've had no official confirmation that any institutional investor is ready to sign up," he said, adding he was "waiting with everyone else".
Yesterday an ACC spokeswoman said the company did not comment on investments it may or may not be considering.
Last week, when Mr Newman was asked if he could provide a timeframe for an announcement on the investor, he said he could not provide a date as it was a project which involved "quite a few moving bits".
To confirm the conditions precedent had been met before investment in the dam could proceed, HBRIC were finalising the "absolutely final details" of the commercial terms between those involved in the capital structure.
The time taken to go through this process would determine the timeframe for financial close.
Information received by Hawke's Bay Today that the Government would announce a funding and investment plan for the Ruataniwha Dam at tomorrow's Hawke's Bay Regional Development Strategy and Action Plan meeting were not able to be confirmed last night.