He said: "We have made bids for a couple of players, but we didn't make them overnight, we made them some time ago.
"Of course, it's absolutely the prerogative of the team to whom we have put these bids in either to accept or not accept as the case may be.
"We wouldn't be the only club in that sort of position, this idea that we are waiting until January 31.
"There may be a host of signings in the next 48 hours, I don't know, but there's every possibility because that seems to have been the way of it in the last number of years."
Sunderland have been strongly linked with Swansea striker Danny Graham although O'Neill has yet to make his interest public.
Graham's appearance as a second-half substitute at the Stadium of Light was booed by sections of the home crowd, a reflection of his Geordie roots and his comments about their club in a fanzine interview
O'Neill said with a smile: "I think he is himself reportedly a Newcastle fan, so I think the reaction to that was probably quite a natural reaction. But Bob Stokoe was looking down at him."