It's not just billionaire Larry Ellison.

Silicon Valley heavyweight Tom Siebel, whose Siebel Systems merged with Mr. Ellison's Oracle in 2006, is also appealing the assessment on his 42-acre estate at 3000 Portola Road in Woodside.

In an appeal dated Sept. 18, 2007, an entity named "3000 Portola Road LLC" claimed that the land's assessed value of $64.7 million had declined to $30 million.

The appeal did not challenge the county's $4 million assessment of the value of buildings and improvements.

No hearing date has been set for the appeal, said Jack Yaco, clerk of the county's Assessment Appeals Board. The property owner is still negotiating with the county assessor as to the value of the property.

If they can agree on a value, the board can approve it without a hearing, Mr. Yaco said. If not, there will be a hearing.

Mark Ong, Mr. Siebel's agent, declined to comment.

Mr. Siebel's property is part of Woodside's historic Mountain Home Ranch, and still includes the adobe built by pioneering lumberman Charles Brown before the Gold Rush. Mr. Siebel bought it from the children of railroad heiress Maude Schroll, who died in 1997.

This is not Mr. Siebel's first encounter with the county assessor. On May 8, 2007, the Assessment Appeals Board issued a decision denying a series of appeals filed by First Virtual Properties LLC, a predecessor to 3000 Portola Road LLC. These appeals challenged the values put on several properties, which Mr. Siebel bought separately from Ms. Schroll's four heirs through some complicated transactions.

In a 15-page decision, the appeals board set the value of the land at $1.4 million per acre, or $58.4 million for the whole estate, as of 2004.

Tip of iceberg?

As news of the housing slump, foreclosures, and Mr. Ellison's $3 million tax refund and dramatically lowered property taxes are making headlines, the assessor's office is seeing a surge of inquiries from others who would like lower tax bills.

"We're seeing significantly more people," said Deputy County Assessor Terrence Flinn.

The increased numbers of inquiries have not yet translated into a surge of appeals, Mr. Yaco said. Appeals of 2008 assessments can be filed between July 2 and Nov. 30. In 2007, the board received about 1,000 appeals, slightly down from the 1,200 in 2006, he said.

"We try to keep current," Mr. Yaco said. "We process appeals as soon as possible, and set hearings as soon as possible."

Mr. Yaco noted that in most areas of San Mateo County, "prices are tending to hold steady. But it takes longer to sell."

Mr. Flinn said the assessor's office is selectively reviewing assessments in areas of the county where property values are declining, such as new subdivisions in East Palo Alto.

Some people may even receive a lower assessment without having to appeal. "We're keeping track of sales and foreclosures." Mr. Flinn said. "We'll pick out areas that need to be reviewed. If we see an obvious situation, we would reduce the assessment.

"But we're not seeing a bunch of foreclosures in Woodside."

INFORMATION: The San Mateo County Assessor's Web site has extensive information on assessments and appeals. Go to smcare.org/homeowner. Or call the assessor's office at 599-1227.

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