Arkansas reaped a windfall when a Walmart founder, James L. Walton, known as Bud, died in 1995 with a fortune estimated by Forbes at $1.65 billion in today’s money. The next year, state estate tax receipts jumped 425 percent, to about $183 million in current dollars.

In an age when bigger fortunes are being made, the states’ prize is getting richer. Research by Enrico Moretti of the University of California, Berkeley, and Daniel J. Wilson of the Federal Reserve Bank of San Francisco estimates that if Jeff Bezos of Amazon died today at his home in the Seattle suburbs, the state tax bill on his estate, estimated by Forbes at more than $100 billion, would add up to almost $12 billion. Washington State’s entire budget for two years is $52 billion.

There’s a hitch to state estate taxes: The rich can move to avoid their reach. That makes counting on the revenues a bit of a crapshoot. If an aging Mr. Bezos moved before he died, establishing his residence in California, his fortune would produce no estate tax revenue.

And yet the payoff from estate taxes can be so big that it’s worthwhile for states to impose them anyway.