Under pressure from Republicans, Teresa Heinz Kerry provided a glimpse of her considerable wealth yesterday, disclosing a 2003 income of $5.1 million, on which she has paid at least $587,000 in federal income taxes so far.

The wife of likely Democratic presidential nominee John F. Kerry, Heinz Kerry inherited a $500 million fortune when her first husband, Sen. H. John Heinz III (R-Pa.), died in a plane crash. Last month, Sen. Kerry (Mass.) released his tax return, which he files separately from his wife, disclosing a $395,000 income that Republicans said belied the family's vast wealth.

The Kerry campaign responded yesterday with a news release that stopped short of full disclosure. The campaign said Heinz Kerry had received an extension of the deadline for filing her 2003 federal income tax return, and would release the first two pages when it is ready in October.

"Today I am making additional public disclosures by releasing my personal tax information," she said in a statement. "John and I believe this strikes a balance between my family's privacy and the media's request for more financial information."

Heinz Kerry reported a taxable income of $2.3 million, primarily from dividends and interest on savings and investments. She earned an additional $2.8 million from tax-exempt bonds. So far, she has paid $587,000 in estimated federal taxes, an effective tax rate of 11.5 percent, compared with the top federal income tax rate of 35 percent.

In April, she paid an additional $280,000 for her 2003 and 2004 federal tax liabilities. Kerry campaign spokesman Michael Meehan said he did not know how much of that payment was for 2003, so he could not say what her total tax liability will be.

In addition, Heinz Kerry disclosed that she distributed more than $4.6 million in charitable contributions through the Heinz Family Foundation, which she and her late husband established.

The disclosure is not likely to quell Republican calls for a broader look at Heinz Kerry's finances. Christine Iverson, a spokeswoman for the Republican National Committee, said the GOP will wait to see what comes out in October.

"On many important occasions, the Kerry campaign has said one thing and done another," she said. "We'll see if this is another one of those occasions."

But Meehan said Heinz Kerry has revealed more than can be expected of a private citizen with no designs on public office. George W. Bush also released a summary of his 1999 income and taxes when he was running for president, followed by a truncated tax release in October 2000, he said.

"She's not a candidate for any office," he said. "He was running for president."

Even from the information released, it is clear that Heinz Kerry was a major benefactor of the tax cut President Bush pushed through last year, which effectively lowered the tax rate on dividends -- her primary source of income -- from 38.6 percent to 15 percent.

Heinz Kerry's effective tax rate is similar to Vice President Cheney's. He and his wife, Lynne V. Cheney, reported an income of $1.9 million in taxable and nontaxable income for 2003 and paid $253,067 in taxes, an effective tax rate of 13.3 percent.