UPDATE 2-Obama budget keeps $250 bln placeholder for banks

(Adds Orszag comments, background)

By Caren Bohan

WASHINGTON, May 7 (Reuters) - The detailed version of President Barack Obama's budget unveiled on Thursday maintains a $250 billion "placeholder" for additional financial rescue efforts should that money be needed, U.S. officials said.

But White House budget director Peter Orszag said the administration hoped it would not need to request the extra bailout funds.

"We are retaining that placeholder, even though, again, that placeholder was out of an abundance of caution and it's very likely -- or it's our hope that -- it will not be necessary to call upon it," Orszag told reporters on a conference call after Obama released a more specific version of the budget document he outlined in February.

If the administration were to officially request the $250 billion, it could finance $750 billion in fresh government aid to the battered U.S. banks, on top of the $700 billion approved by Congress last year.

"Nothing has changed with regards to the Financial Stabilization Plan," said Ken Baer, press secretary for the White House Office of Management and Budget. "It is there just in case that money may be needed."

Baer emphasized that no decision has been made about whether or when to formally request money from Congress for the Troubled Asset Relief Program, also known as TARP.

When it included a reference to the TARP placeholder in the budget document released in February, the administration said that was done in the interests of budget transparency but no decision had been made about whether the money was needed.