WASHINGTON (Reuters) - Securities and Exchange Commission Chair Mary Schapiro, who regulates a wide swathe of Wall Street, is the richest of the Obama administration's top officials with an estimated net worth of $26.6 million, according to a new analysis of U.S. public officials' wealth.

Secretary of State Hillary Clinton comes in second at $21.5 million and Attorney General Eric Holder third at $11.5 million. President Barack Obama is sixth, at $3.7 million, according to the Center for Responsive Politics' latest estimate.

The wealth of the executive branch's top players pales in comparison to members of Congress, some 44 percent of whom are millionaires.

Republican Representative Darrell Issa of California, who earned his fortune making car alarms, tops the list with an estimated wealth of $251 million, the watchdog group said.

Jane Harman, A Democratic representative from California whose husband founded an audio equipment company, comes in second with $244 million.

Democratic Senator Herb Kohl of Wisconsin, who founded a department store chain, is worth $214 million.

Near the other end of the scale, Vice President Joe Biden is worth only $27,000, the group estimated.

He appeared to be better off than Senate Finance Committee Chairman Max Baucus, who owes $42,000 more than he owns, according to the group's estimate.

Members of Congress and top administration officials are required to report their assets and liabilities, but they do not have to provide exact values, only an approximate range. The Center for Responsive Politics reached its estimates by adding together assets and liabilities and estimating the midpoint of the resulting range.

Officials are not required to report the value of their homes.

Other notable Washington officials listed in the report:

* Energy Secretary Steven Chu -- $5.6 million

* Treasury Secretary Timothy Geithner -- $1.3 million Continued...