Death tax 2013

The applicable exclusion amount for the estate tax is $5,250,000 (2013).

The tax rate ranges from 18% (up to $10K) to 35% (over $500K). Not sure what you mean by "ceiling".

The top rate is 40%. Portability is still present, so if one spouse dies and does not use up their exemption, the unused exemption gets carried over the other spouse. It's kind of like an AB trust. It is necessary to file an estate tax return to use the portability even if you owe no tax.

The

on page 5 has rates from 18% to 35%, but it is for deaths in 2012. For 2013 the top rate is 40% but I don't know the table. I suppose the 18% rate is still there and 35% too, but and maybe the 40% is on values above 750k. Strangely no websites talk about these details, or at least it's hard to come by.

For portability an estate tax return has to have been filed for the estate of the first spouse who died, not just the second. I don't know how that will work for spouses who died before portability was enacted.

You could go look at IRS 2001.

The rates are still there, but with a $5 million personal exemption they are essentially meaningless. The lower rates apply below the exemption amount. So at any estate of more than $1 million, there should be a flat rate of 40%, no matter how little or how much over.