Several officials said Republicans want to leave the tax at 35% after exempting the first $5 million in estate value. Officials said the White House wants a 45% tax after a $3.5 million exemption. Without any action by Congress, it would climb to a 55% tax after a $1 million exemption on Jan. 1.
Democrats stressed their unwillingness to make concessions on both income taxes and the estate tax, and said they hoped Republicans would choose which mattered more to them.
Officials said any compromise was likely to ease the impact of the alternative minimum tax, originally designed to make sure that millionaires did not escape taxation. If left unchanged, it could hit an estimated 28 million households for the first time in 2013, with an average increase of more than $3,000.
Taxes on dividends and capital gains are also involved in the talks, as well as a series of breaks for businesses and others due to expire at the first of the year.
Obama and congressional Democrats are insisting on an extension of long-term unemployment benefits that are expiring for about 2 million jobless individuals.
Leaders in both parties also hope to prevent a 27% fee cut from taking effect on Jan. 1 for doctors who treat Medicare patients.
There was also discussion of a short-term extension of expiring farm programs, in part to prevent a spike in milk prices at the first of the year. It wasn't clear whether that was a parallel effort to the cliff talks or had become wrapped into them.
Across-the-board spending cuts that comprise part of the cliff were a different matter.
Republicans say Boehner will insist that they will begin to take effect unless negotiators agreed to offset them with specified savings elsewhere.
That would set the stage for the next round of brinkmanship -- a struggle over Republican calls for savings from Medicare, Medicaid and other federal benefit programs.
The Treasury's ability to borrow is expected to expire in late winter or early spring, and without an increase in the $16.4 trillion limit, the government would face its first-ever default. Republicans have said they will use administration requests for an extension as leverage to win cuts in spending.
Ironically, it was just such a maneuver more than a year ago that set the stage for the current crisis talks over the fiscal cliff.