Manchester United fans can expect further new signings in the coming weeks, executive vice-chairman Ed Woodward has assured them.
New boss Louis van Gaal has already spent £56m on defender Luke Shaw and midfielder Ander Herrera.
And Woodward promised there would be no repeat of last summer's disappointments in the transfer window.
"There is a lot of work going on behind the scenes," Woodward told MUTV. "Watch this space."
Last summer, following the appointment of David Moyes as Sir Alex Ferguson's successor, Woodward failed to secure the club's key targets and ended up signing only Marouane Fellaini for £27m from Everton before the transfer deadline.
Van Gaal is using the club's current trip to the United States to assess what further changes need to be made.
And Woodward has promised the funds are in place to back the manager's plans.
"There is no fixed budget," he said. "Financially we are extremely strong. We want to do what it takes to win the title."
New arrivals will be accompanied by departures. Nemanja Vidic has already joined Inter Milan while Rio Ferdinand has left for QPR and it is anticipated Patrice Evra will join Juventus imminently, having asked United to leave.
Van Gaal has a ready-made replacement for Evra in Shaw, 19, who became the fourth most expensive defender ever when he made a £27m move from Southampton in June.
Former Red Devils full-back Denis Irwin is confident the teenager has the ability required to be a long-term success at the club.
"He has pace, is great going forward and is still only young. He is going to be a fantastic signing for years to come," said Irwin, who made 529 appearances in his 12 years at United.
"Market forces dictate what you have to pay for players and there was talk of Chelsea being in for him.
"We have to accept he will make mistakes defensively. But he has been playing in the Premier League for the last two years with Southampton and he is only going to get better."
United were seventh last season - their worst finish since 1990 - and Van Gaal is looking for an immediate improvement.
Irwin believes United are capable of challenging for the Premier League title in Van Gaal's first season in charge.
"Manchester United have to aim for the summit," he added.
"There are still a lot of experienced players here who know how to get the job done and the manager has won trophies all over the world. With two or three more signings, I would expect us to challenge."