Speaking after the 1-0 FA Cup win at Charlton, Bilic stressed his first priority this month is keeping his squad intact for the second-half of the campaign.
The Baggies have seen youngster Nathan Ferguson linked with a move to Tottenham or Crystal Palace.
West Ham also have until January 14 to recall Grady Diangana from his loan at The Hawthorns.
Both of those players are expected to remain with Albion for the duration of the campaign.
But the Baggies will have a greater idea of what business they need to do this month when their futures have been resolved for certain.
"We’ll see, we will see," Bilic said when asked if fans can expect any signings soon.
"We have to find the balance, between not bringing in players for quantity.
"If we are to bring in numbers, we have to bring in players who are going to make a difference.
"The first thing we must do is keep the players who are with us, the important players, that is something we have to do."
Bilic made 11 changes for the cup tie against the Addicks with a solitary goal from Kenneth Zohore enough to earn them a spot in the fourth round.
The head coach opted to give youth a chance at The Valley with youngsters Jack Fitzwater, Dara O'Shea, Kyle Edwards and Rekeem Harper all impressing.
And Bilic was pleased with his team's display.
"It was a good win, it’s great to go through in the cup," Bilic said.
"It’s good, firstly to rest your players who were tired and to go through and to give the players who haven’t started for some time.
"To give them 90 minutes for their fitness, for their confidence, for everything, is important because we’re going to need them. It’s great.
"I think the performance was, it wasn’t easy only because we didn’t score more goals, but we were the much better team, the dominant team who should’ve scored more goals.
"We’re pleased to be through. It’s also good because we come here in one week, and it’s important to have recent positive memories when we come into the dressing room and onto the pitch.
"Good win, good atmosphere, some young players got chances and made their debuts, for both sides."