March 10, 2008 -- After weeks of intense pressure, and more than a year after announcing her presidential candidacy, Sen. Hillary Clinton has offered little explanation for why she has delayed releasing the tax returns made public by most other Democratic presidential candidates in recent years.

"What is the holdup?" said Sheila Krumholz of the Center for Responsive Politics, a nonprofit group that tracks the role of money in politics. "She hasn't exactly made it clear as to what process is making it so cumbersome to just release them."

Past Democratic presidential candidates have set a precedent for releasing their tax returns before or during the primary season. Sen. John Kerry released his in December of 2003, and former Vice President Al Gore's were in the public domain while he was in office. Clinton's opponent, Sen. Barack Obama, released his 2006 return last April.

"This is a level of disclosure the American people have come to expect and deserve from those in the White House, or those who aspire to the White House," said Mary Boyle of Common Cause, a government reform advocacy group.

The pressure on Clinton to release her tax returns has been intensifying since it was revealed that she loaned her campaign $5 million in January. Clinton had repeatedly stated that she would release her tax returns upon becoming the Democratic nominee, but her spokesman Howard Wolfson said last week that the campaign now planned to release the returns "in or around April 15." Wolfson did not respond to requests for comment for this story.

The lack of disclosure leaves the public with an obscure picture of how the Clintons have managed the multi-million-dollar fortune they have amassed since leaving the White House, say government watchdog groups. Personal financial disclosure filings, required by government ethics rules, only offer a broad glimpse of the Clintons' finances. Since 1999, the couple's net worth has increased from somewhere between $1.25 million and $5.7 million to between $10 million and $50 million, according to filings. In 2006, the Clintons earned hundreds of thousands of dollars from book royalties, and former President Bill Clinton made $10 million in dozens of paid speeches.

The disclosures shed some light on President Clinton's role in two companies run by longtime friends and fundraisers. Clinton earned an unspecified amount as a consultant for InfoUsa, a data company run by longtime friend and fundraiser Vin Gupta, according to the filings. The forms also showed ten of thousands of dollars invested in funds with the Yucaipa Companies, a private equity firm run by another close friend, Ron Burkle.

Many of the specific details surrounding the Clintons' income and assets remain unknown. "The disclosure forms are so limited in what they require," says Krumholz. "For example, there's nothing about your primary house or other houses you live in or use."

Tax forms would help fill in the blanks where the disclosure forms leave off, says Boyle, including exact amounts for income and stock gains and losses as well as details like how much was paid in mortgage interest, charitable deductions and personal exemptions taken.

"In this very extended primary season and competitive environment where people are really struggling to weigh these two candidates, this would be helpful for people to know," said Boyle.

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