Guaraldi took the helm at the Stadio Renato Dall'Ara in 2011 following the resignation of predecessor Marco Pavignani.
The 53-year-old invested €11million in the club to become the majority shareholder, but has come in for criticism from fans after agreeing to sell Saphir Taider and allowing Alberto Gilardino to re-join Genoa.
Guardaldi admits he now regrets rescuing Bologna and is hoping to find a buyer for the Emilia-Romagna club.
"The club is for sale if somebody serious and reliable presents an offer which would cover all of the money I and my partners have invested, my investment is around €11m," he told Radio International.
"I can confirm that I do receive a salary as president of Bologna, but this often only covers the mortgage on the hotel in Carloforte which was left over by (previous president Sergio) Porcedda and has turned from being an asset into a liability.
"If I could go back in time, I would probably not have gained the majority of the club.
"I accepted the presidency because I was pushed to do so by the euphoria of my partners without even considering that I would have created too many expectations among the fans who are now insulting me.
"Right now, I honestly would not know how to win back part of the fans."
Bologna sit 17th in Serie A, having taken just one point from their opening three games. They travel to Udinese on Sunday.
