Mr Grasso, speaking to the Newsweek weekly magazine, said: “If I give back a dime, that’s an admission of guilt. I can’t do that.”
He said he was prepared to forgo $48m in deferred compensation he felt the NYSE still owed him “if they say I’m an honourable man and I did nothing wrong”.
His comments come as Eliot Spitzer, the attorney-general of New York, is said to be preparing a case against Mr Grasso to get back part of his compensation.
Mr Spitzer undertook the effort at the request of the NYSE’s current chairman John Reed, the former Citigroup chief.
The comments appear to soften Mr Grasso’s position that he deserves the entirety of the $187.5m in compensation awarded to him by former boards of the NYSE.
He first expressed this view in February in a rebuttal from his lawyer to Mr Reed’s request for $120m deemed as excessive compensation by the NYSE’s internal review of Mr Grasso’s contracts.
“If [the NYSE does not apologise], let’s go to war,” Mr Grasso told Newsweek.
He had agreed to give up the $48m in deferred pay to quell mounting public furore over his compensation but never formally committed to do so.
In his lawyer’s letter to Mr Reed, the former NYSE chief threatened to countersue for the $48m and additional severance benefits still owed to him by the exchange in case the latter would seek restitution of funds.