The Black Cats made offers earlier this month for United trio Gibson, Wes Brown and John O'Shea. However, while Brown and O'Shea both secured moves to the Stadium of Light, Gibson did not.
"He was at the point of going to Sunderland and somewhere along the line, I don't know exactly when, I think Sunderland moved the goalposts," the Scot told reporters. "I suppose their job is to try and save money.
"From what I can gather, they gave him an offer and then changed it. That annoyed Darron and I think he's quite right.
"If you can't trust them on day one, why wait until day two?"
Ferguson claims that Gibson, who was left out of the club's pre-season tour of America, is currently undecided on his future following the collapse of the move.
"Darron was undecided about what to do when we made the group up to come here," he continued. "We both felt he'd be better staying back. He seems to be in limbo at the moment."