Tim Geithner, the former US Treasury secretary, has been elevated to the highest rank of public speakers, alongside former world leaders Bill Clinton and Tony Blair, after receiving about $400,000 for three speaking engagements.
A speech at a Deutsche Bank conference last month netted him about $200,000, according to people familiar with the situation, underscoring the lucrative fees that former public officials can receive.
Mr Clinton and Mr Blair have both earned millions for speaking at private functions since leaving their relatively low-paid jobs in public office.
(Read More: Billionaire Baron: Geithner Sees Five-Year Fed Exit)
Mr Geithner started offering his take on topics including Federal Reserve policy and the state of the world three months after leaving the Obama administration in January.
He spoke in June alongside Nicolas Sarkozy, France's ex-president, and Mario Monti, Italy's former prime minister, at Deutsche Bank's annual conference in the UK. Mr Geithner gave a speech before taking questions from Peter Hooper, the bank's chief economist who has invited him to participate in a "few client events this year", the bank said.
Mr Geithner was also the main attraction at Blackstone's annual meeting in April, and the following month appeared at Warburg Pincus's annual meeting. He was paid no more than $100,000 by each of the private equity groups, according to people familiar with the matter.
A spokesman for Mr Geithner declined to comment.
(Read More: Placing Odds on Who Will Succeed Bernanke)
Private equity groups compete with each other to host the most glitzy affairs and solicit the biggest names. Last September, Carlyle's co-founder David Rubenstein led a question-and-answer session with Mr Clinton, who charges as much as $200,000, at its annual event.
Former politicians and government officials have long sought to increase their pay with speaking engagements.
However, attending an event immediately after leaving office strikes many former colleagues as unseemly. Within a week of stepping down as Federal Reserve chairman, for example, Alan Greenspan was paid about $250,000 to speak at a dinner for hedge fund clients of the now-defunct Lehman Brothers.
The US custom is not always emulated overseas. When Masaaki Shirakawa stepped down as governor of the Bank of Japan in March, for example, he said he would not speak out on monetary policies or about his experience as central bank governor for at least six months.