Despite insisting he wanted to keep a low profile, Mr Bush has padded his bank account by making scores of speeches paying between $100,000 and $150,000 a time.
The ex-president has made a point of saying he was staying away from politics after retiring to Dallas, Texas.
He turned down an invitation from Barack Obama to attend a ceremony at Ground Zero after Osama bin Laden was killed because he wanted to remain out of the spotlight.
But, according to iWatchNews, Mr Bush made time for three speeches in the week after the 9/11 event.
He earned three six-figure paydays speaking to hedge fund executives in Las Vegas, the UBS Swiss bank in New York and a professional golf gathering in Florida.
In all, Mr Bush is estimated to have delivered as many as 140 paid talks at home and abroad.
Almost all of the speeches are closed to the press so they do not get widespread coverage. So much for the quiet life... George W Bush rakes in staggering $15million on speaking circuit » | David Gardner | Saturday, May 21, 2011
