There's a revolving door between Washington and Wall Street. Here are some of the biggest names to pass through

In Washington: William Simon served as Secretary of the Treasury in the 1970s under President's Nixon and Ford.

On Wall Street: Simon was a DC pioneer in PE. In 1982 he reportedly invested more than $300,000 in one of Wall Street's earliest leveraged buyouts, Gibson Greetings. It netted him more than $66 million and served as inspiration for Carlyle co-CEO David Rubenstein's career.

In Washington: President George H. W. Bush has obviously had a long career: he was 41st President of the US from 1989 to 1993, and spent 8 years as vice president under President Ronald Reagan. Before that, he was a congressman, ambassador and director of the CIA.

On Wall St.: After his career in politics ended, Bush joined private equity firm Carlyle Group as senior advisor to the Carlyle Asia advisory board. He has since retired.

In Washington: After 37 years in the US Army, Petraeus spent just one year running the Central Intelligence Agency before he resigned amid infidelity allegations that surfaced as a result of an FBI investigation.

On Wall St.: The former general made his move to private equity firm KKR long before he had to plead guilty to mishandling classified information; the private equity firm said after Petraeus’ misdemeanor plea he would remain on board.

In Washington: Frank Carlucci served in various international roles. He was deputy secretary of Defense, deputy director of Central Intelligence, and worked in the Office of Management and Budget.

On Wall Street: Carlucci was among the first big names in DC to switch career tracks. He joined the Carlyle Group in 1989 as managing director and became chairman in 1993. He held that role until late 2002, when he was replaced as chair by ex-IBM CEO Lou Gerstner. Today, he's a counselor at the Center for Strategic and International Studies.

In Washington: From 2009 to 2013, Geithner put in critical work serving as the Treasury Department — this, after a six year stint running the Federal Reserve Bank of New York.

On Wall St.: Geithner these days is president at Warburg Pincus, which he joined in late 2013.

In Washington: Jon Samuels served as deputy assistant to the President for legislative affairs. He spent nearly six years working in the White House.

On Wall St.: These days, he can be found at Vistria Group, an Illinois-based middle-market private equity shop focusing on education, financial services and healthcare deals. Vistria is a fund with more than $300 million, founded in part by Marty Nesbitt, who golfs regularly with President Barack Obama.

In Washington: Clark left the US Army at the rank of General after more than three decades of service in 2000. He would then go on to run for President of the United States — as a Democrat — in 2004 and remained active in politics afterwards.

On Wall St.: 2013 was a big year for DC’s political dealmakers to take their talents to Wall Street. That is also when Clark made his move to PE, joining Steve Schwarzman's Blackstone Group.

In Washington: From 2009-2013, DeParle worked in the White House where she was President and Director of the White House Office of Health Reform — and more importantly, she managed the initial implementation of the Affordable Care Act into law. She previously spent time working in the Clinton Administration.

On Wall St.: DeParle went in 2013 to work at healthcare-focused PE firm Consonance Capital Partners in New York. In between stints for the Clinton and Obama administrations, she also worked for JPMorgan.

In Washington: Patrick is best-known for serving as governor of the state of Massachusetts fromfrom 2007 to 2015. In the 1990s, he also was the US Assistant Attorney General for the Civil Rights Division in DC.

On Wall St.: Earlier this year, he joined private equity firm Bain Capital, which was co-founded by his predecessor in the governor’s seat, Mitt Romney.

In Washington: Proving that PE doesn’t just reach into defense and the White House, Bruce Karpati once served as the SEC enforcement division's chief of asset management.

On Wall St.: Today, he’s head of compliance for KKR, which he joined in 2014.

In Washington: Grady spent four years as a senior policy advisor to President George H. W. Bush. Other roles in DC for Grady include his role as deputy assistant to the President, executive director of the Office of Management & Budget and other policy roles.

On Wall St.: He the Carlyle Group for a nine-year stint beginning in 2000, and these days he's head of Gryphon Investors’ general industries group, which he joined earlier this year. The private equity firm is based in San Francisco, but Grady’s LinkedIn profile says he’s in Wyoming.

In Washington: Kennard is a Beltway veteran. In the late 1990s, he cut his teeth in the DC scene as FCC commissioner and after his tenure there concluded, he was lured into PE firm Carlyle Group.

On Wall St.: Kennard would take two trips between PE and DC, however. He returned to the political scene after leaving Carlyle, and served as US ambassador to the EU. Once that concluded in 2013, he returned to the fold in PE again, this time joining Grain Management as senior advisor to the EU.

In Washington: Evan Bayh quickly rose through the ranks, from being Indiana’s Secretary of State to its Governor, to next serving as Senator in Washington, DC.

On Wall St.: Bayh took a job at Apollo Global Management in 2011. These days, he can be found at K Street firm McGuireWoods Consulting.

In Washington: Lieberman spent more than two decades around the Beltway, all of it as US Senator from the state of Connecticut. He was also on Al Gore’s failed presidential ticket in 2000.

On Wall St.: Just last year, middle market investing firm Victory Park Capital announced Leiberman would join as chairman of its executive board.

In Washington: After beginning his career in the private sector, Julius Genachowski spent four years as chairman of the Federal Communications Commission, leaving in 2013.

On Wall St.: Once he left the regulatory realm, Genachowski stayed in DC, joining private equity firm the Carlyle Group as a managing director on its telecom team.