AFC Bournemouth have signed Christian Atsu from Chelsea on a season-long loan deal.
Midfielder Miguel Pallardo has signed a new one-year deal with newly-promoted Hearts while Danny Wilson leaves.
Despite currently riding high in fourth, having been beaten just once in the Barclays Premier League, the Scot does not expect to be able to bring in players to consolidate their position when the transfer window reopens.
"I don't think we'll strengthen in January," said Moyes.
"I don't think we'll be looking to do any business - not because we wouldn't want to but I just don't think we will have the resources to properly do it in January."
In the summer transfer window Moyes completed most of his signings early, bringing in the likes of Steven Naismith, Kevin Mirallas and re-signing Steven Pienaar from Tottenham.
Prior to that he splashed out on Rangers striker Nikica Jelavic and Manchester United midfielder Darron Gibson in January.