The Red Devils have already completed deals for Shinji Kagawa and Nick Powell but the manager revealed they are still trying to strengthen their squad ahead of the new season
On the chances of signing more players, he told MUTV: "Yes, there's a possibility. We're working on one or two things but there's nothing really to tell you to be honest."
The Red Devils have already completed deals for Shinji Kagawa from Borussia Dortmund and Nick Powell from Crewe but continued to be linked a host of other players including Leighton Baines and Joao Moutinho.
Sir Alex is pleased with how the club's summer transfer activity has panned out so far but conceded completing deals to bring players to the club can prove a long process.
"We always try to get our work done at the end of the season – we spent a good deal of time sorting the deal with Shinji and we'd agreed a deal with Nick Powell before the playoffs which was a good move by us because the boy had an outstanding final at Wembley," Ferguson said.
"When you don't get deals done immediately and you're negotiating with a club over a long period, then you can't expect to just snap your fingers and get it done."