There has been speculation about a possible takeover for some
time and Shepherd wants any potential investors to make their
intentions clear.
He added that he would happily walk away from the club if a
"billionaire" investor could be found.
"It's about finding whatever is best for the club," he said at the
club's annual general meeting on Tuesday.
"Multi-millionaires are not enough any longer, you need
billionaires.
"We would have to make sure that they would be fit and proper
people to take over.
"It would be a clean break. I would not hang on, that's not right
for any company."
Newcastle and Belgravia Group have been engaged in formal
discussions since August, while American group Polygon were
reported last week to be interested.
Shepherd added: "I would like it sorted out as soon as
possible.
"Enough is enough. It has not affected the team or the management
but, the longer it goes on, it makes for a lot of uncertainty
around the club.
"It is time they put up or shut up, it is as simple as that. I
don't make the rules, I abide by them. Let's get on with it."
